International Nuclear Information System (INIS)
Kaplan, I.G.; Rodimova, O.B.; AN SSSR, Tomsk. Inst. Optiki Atmosfery)
1978-01-01
The present state of the intermolecular interaction theory is described. The general physical picture of the molecular interactions is given, the relative contributions of interactions of different types are analyzed (electrostatic, resonance, induction, dispersion, relativistic, magnetostatic and exchange), and the main ones in each range of separations are picked out. The methods of the potential curve calculations are considered, specific for definite separations between the interacting systems. The special attention is paid to the analysis of approximations used in different theoretical calculation methods
The effect of strong intermolecular and chemical interactions on the compatibility of polymers
International Nuclear Information System (INIS)
Askadskii, Andrei A
1999-01-01
The data on compatibility and on the properties of polymer blends are generalised. The emphasis is placed on the formation of strong intermolecular interactions (dipole-dipole interaction and hydrogen bonding) between the components of blends, as well as on the chemical reactions between them. A criterion for the prediction of compatibility of polymers is described in detail. Different cases of compatibility are considered and the dependences of the glass transition temperatures on the composition of blends are analysed. The published data on the effect of strong intermolecular interactions between the blend components on the glass transition temperature are considered. The preparation of interpolymers is described whose macromolecules are composed of incompatible polymers, which leads to the so-called 'forced compatibility.' The bibliography includes 80 references.
Characterizing the Polymer:Fullerene Intermolecular Interactions
Sweetnam, Sean
2016-02-02
Polymer:fullerene solar cells depend heavily on the electronic coupling of the polymer and fullerene molecular species from which they are composed. The intermolecular interaction between the polymer and fullerene tends to be strong in efficient photovoltaic systems, as evidenced by efficient charge transfer processes and by large changes in the energetics of the polymer and fullerene when they are molecularly mixed. Despite the clear presence of these strong intermolecular interactions between the polymer and fullerene, there is not a consensus on the nature of these interactions. In this work, we use a combination of Raman spectroscopy, charge transfer state absorption, and density functional theory calculations to show that the intermolecular interactions do not appear to be caused by ground state charge transfer between the polymer and fullerene. We conclude that these intermolecular interactions are primarily van der Waals in nature. © 2016 American Chemical Society.
Single-molecule magnets ``without'' intermolecular interactions
Wernsdorfer, W.; Vergnani, L.; Rodriguez-Douton, M. J.; Cornia, A.; Neugebauer, P.; Barra, A. L.; Sorace, L.; Sessoli, R.
2012-02-01
Intermolecular magnetic interactions (dipole-dipole and exchange) affect strongly the magnetic relaxation of crystals of single-molecule magnets (SMMs), especially at low temperature, where quantum tunneling of the magnetization (QTM) dominates. This leads to complex many-body problems [l]. Measurements on magnetically diluted samples are desirable to clearly sort out the behaviour of magnetically-isolated SMMs and to reveal, by comparison, the effect of intermolecular interactions. Here, we diluted a Fe4 SMM into a diamagnetic crystal lattice, affording arrays of independent and iso-oriented magnetic units. We found that the resonant tunnel transitions are much sharper, the tunneling efficiency changes significantly, and two-body QTM transitions disappear. These changes have been rationalized on the basis of a dipolar shuffling mechanism and of transverse dipolar fields, whose effect has been analyzed using a multispin model. Our findings directly prove the impact of intermolecular magnetic couplings on the SMM behaviour and disclose the magnetic response of truly-isolated giant spins in a diamagnetic crystalline environment.[4pt] [1] W. Wernsdorfer, at al, PRL 82, 3903 (1999); PRL 89, 197201 (2002); Nature 416, 406 (2002); IS Tupitsyn, PCE Stamp, NV Prokof'ev, PRB 69, 132406 (2004).
Characterizing the Polymer:Fullerene Intermolecular Interactions
Sweetnam, Sean; Vandewal, Koen; Cho, Eunkyung; Risko, Chad; Coropceanu, Veaceslav; Salleo, Alberto; Bredas, Jean-Luc; McGehee, Michael D.
2016-01-01
the polymer and fullerene, there is not a consensus on the nature of these interactions. In this work, we use a combination of Raman spectroscopy, charge transfer state absorption, and density functional theory calculations to show that the intermolecular
Quantifying intermolecular interactions of ionic liquids using cohesive energy densities
2017-01-01
For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced, is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, cedIP, where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, cedC+A, where the ionic vapour constituents are isolated ions. A cedIP dataset is presented for 64 ILs. For the first time an experimental cedC+A, a measure of the strength of the total intermolecular interaction for an IL, is presented. cedC+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between cedIP and the inverse of the molecular volume. A good linear correlation is found between IL cedIP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to cedIP. These findings show that cedIP is very important for understanding IL intermolecular interactions, in spite of cedIP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined. PMID:29308254
Quantifying intermolecular interactions of ionic liquids using cohesive energy densities.
Lovelock, Kevin R J
2017-12-01
For ionic liquids (ILs), both the large number of possible cation + anion combinations and their ionic nature provide a unique challenge for understanding intermolecular interactions. Cohesive energy density, ced , is used to quantify the strength of intermolecular interactions for molecular liquids, and is determined using the enthalpy of vaporization. A critical analysis of the experimental challenges and data to obtain ced for ILs is provided. For ILs there are two methods to judge the strength of intermolecular interactions, due to the presence of multiple constituents in the vapour phase of ILs. Firstly, ced IP , where the ionic vapour constituent is neutral ion pairs, the major constituent of the IL vapour. Secondly, ced C+A , where the ionic vapour constituents are isolated ions. A ced IP dataset is presented for 64 ILs. For the first time an experimental ced C+A , a measure of the strength of the total intermolecular interaction for an IL, is presented. ced C+A is significantly larger for ILs than ced for most molecular liquids, reflecting the need to break all of the relatively strong electrostatic interactions present in ILs. However, the van der Waals interactions contribute significantly to IL volatility due to the very strong electrostatic interaction in the neutral ion pair ionic vapour. An excellent linear correlation is found between ced IP and the inverse of the molecular volume. A good linear correlation is found between IL ced IP and IL Gordon parameter (which are dependent primarily on surface tension). ced values obtained through indirect methods gave similar magnitude values to ced IP . These findings show that ced IP is very important for understanding IL intermolecular interactions, in spite of ced IP not being a measure of the total intermolecular interactions of an IL. In the outlook section, remaining challenges for understanding IL intermolecular interactions are outlined.
International Nuclear Information System (INIS)
Froissart, Marcel
1976-01-01
Strong interactions are introduced by their more obvious aspect: nuclear forces. In hadron family, the nucleon octet, OMEGA - decuplet, and quark triply are successively considered. Pion wave having been put at the origin of nuclear forces, low energy phenomena are described, the force being explained as an exchange of structure corresponding to a Regge trajectory in a variable rotating state instead of the exchange of a well defined particle. At high energies the concepts of pomeron, parton and stratons are introduced, pionization and fragmentation are briefly differentiated [fr
Intermolecular interactions in the condensed phase
DEFF Research Database (Denmark)
Christensen, Anders S.; Kromann, Jimmy Charnley; Jensen, Jan Halborg
2017-01-01
To facilitate further development of approximate quantum mechanical methods for condensed phase applications, we present a new benchmark dataset of intermolecular interaction energies in the solution phase for a set of 15 dimers, each containing one charged monomer. The reference interaction energy...... and solution phases. As most approximate QM methods are parametrized and evaluated using data measured or calculated in the gas phase, the dataset represents an important first step toward calibrating QM based methods for application in the condensed phase where polarization and exchange repulsion need...
Park, Sarah S; Hendon, Christopher H; Fielding, Alistair J; Walsh, Aron; O'Keeffe, Michael; Dincă, Mircea
2017-03-15
The structure-directing role of the inorganic secondary building unit (SBU) is key for determining the topology of metal-organic frameworks (MOFs). Here we show that organic building units relying on strong π interactions that are energetically competitive with the formation of common inorganic SBUs can also play a role in defining the topology. We demonstrate the importance of the organic SBU in the formation of Mg 2 H 6 (H 3 O)(TTFTB) 3 (MIT-25), a mesoporous MOF with the new ssp topology. A delocalized electronic hole is critical in the stabilization of the TTF triad organic SBUs and exemplifies a design principle for future MOF synthesis.
Intermolecular interaction studies of glyphosate with water
Manon, Priti; Juglan, K. C.; Kaur, Kirandeep; Sethi, Nidhi; Kaur, J. P.
2017-07-01
The density (ρ), viscosity (η) and ultrasonic velocity (U) of glyphosate with water have been measured on different ultrasonic frequency ranges from 1MHz, 2MHz, 3MHz & 5MHz by varying concentrations (0.05%, 0.10%, 0.15%, 0.20%, 0.25%, 0.30%, 0.35%, & 0.40%) at 30°C. The specific gravity bottle, Ostwald's viscometer and quartz crystal interferometer were used to determine density (ρ), viscosity (η) and ultrasonic velocity (U). These three factors contribute in evaluating the other parameters as acoustic impedance (Z), adiabatic compressibility (β), relaxation time (τ), intermolecular free length (Lf), free volume (Vf), ultrasonic attenuation (α/f2), Rao's constant (R), Wada's constant (W) and relative strength (R). Solute-solvent interaction is confirmed by ultrasonic velocity and viscosity values, which increases with increase in concentration indicates stronger association between solute and solvent molecules. With rise in ultrasonic frequency the interaction between the solute and solvent particles decreases. The linear variations in Rao's constant and Wada's constant suggest the absence of complex formation.
The origins of the directionality of noncovalent intermolecular interactions.
Wang, Changwei; Guan, Liangyu; Danovich, David; Shaik, Sason; Mo, Yirong
2016-01-05
The recent σ-hole concept emphasizes the contribution of electrostatic attraction to noncovalent bonds, and implies that the electrostatic force has an angular dependency. Here a set of clusters, which includes hydrogen bonding, halogen bonding, chalcogen bonding, and pnicogen bonding systems, is investigated to probe the magnitude of covalency and its contribution to the directionality in noncovalent bonding. The study is based on the block-localized wavefunction (BLW) method that decomposes the binding energy into the steric and the charge transfer (CT) (hyperconjugation) contributions. One unique feature of the BLW method is its capability to derive optimal geometries with only steric effect taken into account, while excluding the CT interaction. The results reveal that the overall steric energy exhibits angular dependency notably in halogen bonding, chalcogen bonding, and pnicogen bonding systems. Turning on the CT interactions further shortens the intermolecular distances. This bond shortening enhances the Pauli repulsion, which in turn offsets the electrostatic attraction, such that in the final sum, the contribution of the steric effect to bonding is diminished, leaving the CT to dominate the binding energy. In several other systems particularly hydrogen bonding systems, the steric effect nevertheless still plays the major role whereas the CT interaction is minor. However, in all cases, the CT exhibits strong directionality, suggesting that the linearity or near linearity of noncovalent bonds is largely governed by the charge-transfer interaction whose magnitude determines the covalency in noncovalent bonds. © 2015 Wiley Periodicals, Inc.
Connecting Protein Structure to Intermolecular Interactions: A Computer Modeling Laboratory
Abualia, Mohammed; Schroeder, Lianne; Garcia, Megan; Daubenmire, Patrick L.; Wink, Donald J.; Clark, Ginevra A.
2016-01-01
An understanding of protein folding relies on a solid foundation of a number of critical chemical concepts, such as molecular structure, intra-/intermolecular interactions, and relating structure to function. Recent reports show that students struggle on all levels to achieve these understandings and use them in meaningful ways. Further, several…
Testing strong interaction theories
International Nuclear Information System (INIS)
Ellis, J.
1979-01-01
The author discusses possible tests of the current theories of the strong interaction, in particular, quantum chromodynamics. High energy e + e - interactions should provide an excellent means of studying the strong force. (W.D.L.)
Quantitative analysis of intermolecular interactions in orthorhombic rubrene
Directory of Open Access Journals (Sweden)
Venkatesha R. Hathwar
2015-09-01
Full Text Available Rubrene is one of the most studied organic semiconductors to date due to its high charge carrier mobility which makes it a potentially applicable compound in modern electronic devices. Previous electronic device characterizations and first principles theoretical calculations assigned the semiconducting properties of rubrene to the presence of a large overlap of the extended π-conjugated core between molecules. We present here the electron density distribution in rubrene at 20 K and at 100 K obtained using a combination of high-resolution X-ray and neutron diffraction data. The topology of the electron density and energies of intermolecular interactions are studied quantitatively. Specifically, the presence of Cπ...Cπ interactions between neighbouring tetracene backbones of the rubrene molecules is experimentally confirmed from a topological analysis of the electron density, Non-Covalent Interaction (NCI analysis and the calculated interaction energy of molecular dimers. A significant contribution to the lattice energy of the crystal is provided by H—H interactions. The electron density features of H—H bonding, and the interaction energy of molecular dimers connected by H—H interaction clearly demonstrate an importance of these weak interactions in the stabilization of the crystal structure. The quantitative nature of the intermolecular interactions is virtually unchanged between 20 K and 100 K suggesting that any changes in carrier transport at these low temperatures would have a different origin. The obtained experimental results are further supported by theoretical calculations.
Wang, Hui; Liu, Ju; Wang, Weizhou
2018-02-14
Single-crystal X-ray diffraction reveals that polymorphic ortho-nitrophenyl selenocyanate (o-NSC, crystals 1a and 1b) and monomorphic para-nitrophenyl selenocyanate (p-NSC, crystal 2) crystals are all stabilized mainly by intermolecular and very strong intramolecular C-SeO/N chalcogen bonds, as well as by other different interactions. Thermogravimetric (TG) and differential scanning calorimetry thermogram (DSC) analyses show that the starting decomposition temperatures and melting points of the three crystals are different, following the order 1b > 1a > 2, which is consistent with the structural characteristics of the crystals. In addition, atoms in molecules (AIM) and natural bond orbital (NBO) analyses indicate that the total strengths of the C-SeO and C-SeN chalcogen bonds decrease in the order 1b > 1a > 2. This study could be significant for engineering functional crystals based on robust C-SeO and C-SeN chalcogen bonds, and for designing drugs containing selenium as well as understanding their interaction in biosystems.
Modeling Adsorption-Desorption Processes at the Intermolecular Interactions Level
Varfolomeeva, Vera V.; Terentev, Alexey V.
2018-01-01
Modeling of the surface adsorption and desorption processes, as well as the diffusion, are of considerable interest for the physical phenomenon under study in ground tests conditions. When imitating physical processes and phenomena, it is important to choose the correct parameters to describe the adsorption of gases and the formation of films on the structural materials surface. In the present research the adsorption-desorption processes on the gas-solid interface are modeled with allowance for diffusion. Approaches are proposed to describe the adsorbate distribution on the solid body surface at the intermolecular interactions level. The potentials of the intermolecular interaction of water-water, water-methane and methane-methane were used to adequately modeling the real physical and chemical processes. The energies calculated by the B3LYP/aug-cc-pVDZ method. Computational algorithms for determining the average molecule area in a dense monolayer, are considered here. Differences in modeling approaches are also given: that of the proposed in this work and the previously approved probabilistic cellular automaton (PCA) method. It has been shown that the main difference is due to certain limitations of the PCA method. The importance of accounting the intermolecular interactions via hydrogen bonding has been indicated. Further development of the adsorption-desorption processes modeling will allow to find the conditions for of surface processes regulation by means of quantity adsorbed molecules control. The proposed approach to representing the molecular system significantly shortens the calculation time in comparison with the use of atom-atom potentials. In the future, this will allow to modeling the multilayer adsorption at a reasonable computational cost.
Strongly interacting Fermi gases
Directory of Open Access Journals (Sweden)
Bakr W.
2013-08-01
Full Text Available Strongly interacting gases of ultracold fermions have become an amazingly rich test-bed for many-body theories of fermionic matter. Here we present our recent experiments on these systems. Firstly, we discuss high-precision measurements on the thermodynamics of a strongly interacting Fermi gas across the superfluid transition. The onset of superfluidity is directly observed in the compressibility, the chemical potential, the entropy, and the heat capacity. Our measurements provide benchmarks for current many-body theories on strongly interacting fermions. Secondly, we have studied the evolution of fermion pairing from three to two dimensions in these gases, relating to the physics of layered superconductors. In the presence of p-wave interactions, Fermi gases are predicted to display toplogical superfluidity carrying Majorana edge states. Two possible avenues in this direction are discussed, our creation and direct observation of spin-orbit coupling in Fermi gases and the creation of fermionic molecules of 23Na 40K that will feature strong dipolar interactions in their absolute ground state.
Modulation of intermolecular interactions in single-molecule magnets
Heroux, Katie Jeanne
Polynuclear manganese clusters exhibiting interesting magnetic and quantum properties have been an area of intense research since the discovery of the first single-molecule magnet (SMM) in 1993. These molecules, below their blocking temperature, function as single-domain magnetic particles which exhibit classical macroscale magnetic properties as well as quantum mechanical phenomena such as quantum tunnelling of magnetization (QTM) and quantum phase interference. The union of classical and quantum behavior in these nanomaterials makes SMMs ideal candidates for high-density information storage and quantum computing. However, environmental coupling factors (nuclear spins, phonons, neighboring molecules) must be minimized if such applications are ever to be fully realized. The focus of this work is making small structural changes in well-known manganese SMMs in order to drastically enhance the overall magnetic and quantum properties of the system. Well-isolated molecules of high crystalline quality should lead to well-defined energetic and spectral properties as well. An advantage of SMMs over bulk magnetic materials is that they can be chemically altered from a "bottom-up" approach providing a synthetic tool for tuning magnetic properties. This systematic approach is utilized in the work presented herein by incorporating bulky ligands and/or counterions to "isolate" the magnetic core of [Mn4] dicubane SMMs. Reducing intermolecular interactions in the crystal lattice (neighboring molecules, solvate molecules, dipolar interactions) is an important step toward developing viable quantum computing devices. Detailed bulk magnetic studies as well as single crystal magnetization hysteresis and high-frequency EPR studies on these sterically-isolated complexes show enhanced, and sometimes even unexpected, quantum dynamics. The importance of intra- and intermolecular interactions remains a common theme throughout this work, extending to other SMMs of various topology including
Strongly interacting Higgs bosons
International Nuclear Information System (INIS)
Appelquist, T.; Bernard, C.
1980-01-01
The sensitivity of present-energy weak interactions to a strongly interacting heavy-Higgs-boson sector is discussed. The gauged nonlinear sigma model, which is the limit of the linear model as the Higgs-boson mass goes to infinity, is used to organize and catalogue all possible heavy-Higgs-boson effects. As long as the SU(2)/sub L/ x SU(2)/sub R/ symmetry of the Higgs sector is preserved, these effects are found to be small, of the order of the square of the gauge coupling times logarithms (but not powers) of the Higgs-boson mass divided by the W mass. We work in the context of a simplified model with gauge group SU(2)/sub L/; the extension to SU(2)/sub L/ x U(1) is briefly discussed
Intermolecular Interactions in Ternary Glycerol–Sample–H2O
DEFF Research Database (Denmark)
Westh, Peter; Rasmussen, Erik Lumby; Koga, Yoshikata
2011-01-01
We studied the intermolecular interactions in ternary glycerol (Gly)–sample (S)–H2O systems at 25 °C. By measuring the excess partial molar enthalpy of Gly, HGlyEHEGly, we evaluated the Gly–Gly enthalpic interaction, HGly-GlyEHEGly--Gly, in the presence of various samples (S). For S, tert...... little effect on HGly-GlyEHEGly--Gly. This contrasts with our earlier studies on 1P–S–H2O in that Na+, F− and Cl− are found as hydration centers from the induced changes on HIP-IPEHEIP--IP in the presence of S, while Br−, I−, and SCN− are found to act as hydrophiles. In comparison with the Hofmeister...... ranking of these ions, the kosmotropes are hydration centers and the more kosmotropic the higher the hydration number, consistent with the original Hofmeister’s concept of “H2O withdrawing power.” Br−, I− and SCN−, on the other hand, acted as hydrophiles and the more chaotropic they are the more...
Localized-overlap approach to calculations of intermolecular interactions
Rob, Fazle
Symmetry-adapted perturbation theory (SAPT) based on the density functional theory (DFT) description of the monomers [SAPT(DFT)] is one of the most robust tools for computing intermolecular interaction energies. Currently, one can use the SAPT(DFT) method to calculate interaction energies of dimers consisting of about a hundred atoms. To remove the methodological and technical limits and extend the size of the systems that can be calculated with the method, a novel approach has been proposed that redefines the electron densities and polarizabilities in a localized way. In the new method, accurate but computationally expensive quantum-chemical calculations are only applied for the regions where it is necessary and for other regions, where overlap effects of the wave functions are negligible, inexpensive asymptotic techniques are used. Unlike other hybrid methods, this new approach is mathematically rigorous. The main benefit of this method is that with the increasing size of the system the calculation scales linearly and, therefore, this approach will be denoted as local-overlap SAPT(DFT) or LSAPT(DFT). As a byproduct of developing LSAPT(DFT), some important problems concerning distributed molecular response, in particular, the unphysical charge-flow terms were eliminated. Additionally, to illustrate the capabilities of SAPT(DFT), a potential energy function has been developed for an energetic molecular crystal of 1,1-diamino-2,2-dinitroethylene (FOX-7), where an excellent agreement with the experimental data has been found.
Strong-interaction nonuniversality
International Nuclear Information System (INIS)
Volkas, R.R.; Foot, R.; He, X.; Joshi, G.C.
1989-01-01
The universal QCD color theory is extended to an SU(3) 1 direct product SU(3) 2 direct product SU(3) 3 gauge theory, where quarks of the ith generation transform as triplets under SU(3)/sub i/ and singlets under the other two factors. The usual color group is then identified with the diagonal subgroup, which remains exact after symmetry breaking. The gauge bosons associated with the 16 broken generators then form two massive octets under ordinary color. The interactions between quarks and these heavy gluonlike particles are explicitly nonuniversal and thus an exploration of their physical implications allows us to shed light on the fundamental issue of strong-interaction universality. Nonuniversality and weak flavor mixing are shown to generate heavy-gluon-induced flavor-changing neutral currents. The phenomenology of these processes is studied, as they provide the major experimental constraint on the extended theory. Three symmetry-breaking scenarios are presented. The first has color breaking occurring at the weak scale, while the second and third divorce the two scales. The third model has the interesting feature of radiatively induced off-diagonal Kobayashi-Maskawa matrix elements
Strong interaction phenomenology
International Nuclear Information System (INIS)
Giffon, M.
1989-01-01
A brief review of high energy hadronic data (Part I)is followed by an introduction to the standard (Weinberg Salam Glashow) model of electroweak interactions and its extension to the hadrons (Part II). Rudiments of QCD and of the parton model area given in Part III together with a quick review of the spectroscopy of heavy flavours whereas Part IV is devoted to the introduction to deep inelastic scattering and to the so-called EMC effects. (author)
Strong Intermolecular Exciton Couplings in Solid-State Circular Dichroism of Aryl Benzyl Sulfoxides
Czech Academy of Sciences Publication Activity Database
Padula, Daniele; Di Pietro, S.; Capozzi, M. A. M.; Cardellicchio, C.; Pescitelli, G.
2014-01-01
Roč. 26, č. 9 (2014), s. 462-470 ISSN 0899-0042 Institutional support: RVO:61388963 Keywords : organic crystals * TDDFT CD calculations * pairwise additive approximation * two-body effects * intermolecular forces in crystal lattices Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.886, year: 2014
Effects of Weak Intermolecular Interactions on the Molecular Isomerism of Tricobalt Metal Chains
International Nuclear Information System (INIS)
Poulsen, R.; Overgaard, J.; Schulman, A.; Stergaard, C.; Murillo, C.; Spackman, M.; Iversen, B.
2009-01-01
Depending on the number of interstitial solvent molecules, n, crystals of the linear chain compound Co3(dipyridylamide)4Cl2·nCH2Cl2 adopt either symmetrical or unsymmetrical metal chain structures. We explore here the possible reasons for such behavior using Hirshfeld surface analysis of intermolecular interactions as well as the charge density determined from 100(1) K X-ray diffraction data on the unsymmetrical complex Co3(dipyridylamide)4Cl2·2.11CH2Cl2, u-1, and crystal structures of u-1 determined from single crystal synchrotron X-ray diffraction data at 20, 150, and 300 K. The new crystal structures are compared with previous structural results on a crystal with slightly different solvent content. This change in solvent content only affects the bond distances to atom Co(3), which are also strongly affected by temperature changes due to a spin crossover transition. Large differences in intermolecular interactions are revealed by the Hirshfeld surface analysis between symmetrical (s-1) and unsymmetrical (u-1) crystal solvates, suggesting that the molecular isomerism is strongly influenced by crystal packing effects. Topological analysis of the static electron density of u-1 suggests that there is direct metal-metal bonding for both the shorter Co(1)-Co(2) and the longer Co(2)-Co(3) contact. The approximate description of the system as a (Co2)2+-dimer and an isolated Co2+-ion is reflected in the character of the metal-ligand interactions, which are more ionic for the isolated Co(3) atom, and the topological charges Co(1)+0.50, Co(2)+0.77, and Co(3)+1.36. The two termini of u-1 are found to be very different, both in terms of structural surroundings as well as topology. The central Co(2) atom is similar to a cobalt atom in a tetragonally distorted octahedral environment resulting in preferred occupancy in the t2g orbitals. The Co(1) atom has significant deformation in the xz and yz planes (z along the chain axis, x and y toward ligands) reflecting covalent
Intermolecular interaction potentials of the methane dimer from the local density approximation
International Nuclear Information System (INIS)
Chen Xiangrong; Bai Yulin; Zhu Jun; Yang Xiangdong
2004-01-01
The intermolecular interaction potentials of methane (CH 4 ) dimer are calculated within the density functional theory in the local density approximation (LDA). It is found that the calculated potentials have minima when the intermolecular distance of CH 4 dimer is about 7.0 a.u., which is in good agreement with the experiment. The depth of the potential is 0.017 eV. The results obtained by our LDA calculations seem to agree well with those obtained by MP2, MP3, and CCSD from the Moeller-Plesset and coupled cluster methods by Tsuzuki et al. and with the experimental data
Strong interactions at high energy
International Nuclear Information System (INIS)
Anselmino, M.
1995-01-01
Spin effects in strong interaction high energy processes are subtle phenomena which involve both short and long distance physics and test perturbative and non perturbative aspects of QCD. Moreover, depending on quantities like interferences between different amplitudes and relative phases, spin observables always test a theory at a fundamental quantum mechanical level; it is then no surprise that spin data are often difficult to accommodate within the existing models. A report is made on the main issues and contributions discussed in the parallel Session on the open-quote open-quote Strong interactions at high energy close-quote close-quote in this Conference. copyright 1995 American Institute of Physics
Helping Students Assess the Relative Importance of Different Intermolecular Interactions
Jasien, Paul G.
2008-01-01
A semi-quantitative model has been developed to estimate the relative effects of dispersion, dipole-dipole interactions, and H-bonding on the normal boiling points ("T[subscript b]") for a subset of simple organic systems. The model is based upon a statistical analysis using multiple linear regression on a series of straight-chain organic…
Vibrational spectroscopy on intermolecular interactions in solutions and at interfaces
Nissink, Johannes Wilhelmus Maria
1999-01-01
In recent years, considerable progress has been made in the areas of molecular recognition and surface analysis. These fields meet in the field of sensor development, where the interaction between molecules and a suitably modified surface is of utmost importance. Vibrational spectroscopy is quite
The colours of strong interaction
International Nuclear Information System (INIS)
1995-01-01
The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)
Atom depth analysis delineates mechanisms of protein intermolecular interactions
International Nuclear Information System (INIS)
Alocci, Davide; Bernini, Andrea; Niccolai, Neri
2013-01-01
Highlights: •3D atom depth analysis is proposed to identify different layers in protein structures. •Amino acid contents for each layers have been analyzed for a large protein dataset. •Charged amino acids in the most external layer are present at very different extents. •Atom depth indexes of K residues reflect their side chains flexibility. •Mobile surface charges can be responsible for long range protein–protein recognition. -- Abstract: The systematic analysis of amino acid distribution, performed inside a large set of resolved protein structures, sheds light on possible mechanisms driving non random protein–protein approaches. Protein Data Bank entries have been selected using as filters a series of restrictions ensuring that the shape of protein surface is not modified by interactions with large or small ligands. 3D atom depth has been evaluated for all the atoms of the 2,410 selected structures. The amino acid relative population in each of the structural layers formed by grouping atoms on the basis of their calculated depths, has been evaluated. We have identified seven structural layers, the inner ones reproducing the core of proteins and the outer one incorporating their most protruding moieties. Quantitative analysis of amino acid contents of structural layers identified, as expected, different behaviors. Atoms of Q, R, K, N, D residues are increasingly more abundant in going from core to surfaces. An opposite trend is observed for V, I, L, A, C, and G. An intermediate behavior is exhibited by P, S, T, M, W, H, F and Y. The outer structural layer hosts predominantly E and K residues whose charged moieties, protruding from outer regions of the protein surface, reorient free from steric hindrances, determining specific electrodynamics maps. This feature may represent a protein signature for long distance effects, driving the formation of encounter complexes and the eventual short distance approaches that are required for protein
Berry, David J; Steed, Jonathan W
2017-08-01
As small molecule drugs become harder to develop and less cost effective for patient use, efficient strategies for their property improvement become increasingly important to global health initiatives. Improvements in the physical properties of Active Pharmaceutical Ingredients (APIs), without changes in the covalent chemistry, have long been possible through the application of binary component solids. This was first achieved through the use of pharmaceutical salts, within the last 10-15years with cocrystals and more recently coamorphous systems have also been consciously applied to this problem. In order to rationally discover the best multicomponent phase for drug development, intermolecular interactions need to be considered at all stages of the process. This review highlights the current thinking in this area and the state of the art in: pharmaceutical multicomponent phase design, the intermolecular interactions in these phases, the implications of these interactions on the material properties and the pharmacokinetics in a patient. Copyright © 2017 Elsevier B.V. All rights reserved.
Sutton, Christopher; Marshall, Michael S.; Sherrill, C. David; Risko, Chad; Bredas, Jean-Luc
2015-01-01
exchange-repulsion interactions among the phenyl side groups. Calculations based on available crystallographic structures reveal that planar conformations of the tetracene core in the solid state result from intermolecular interactions that can be tuned
Strongly interacting light dark matter
International Nuclear Information System (INIS)
Bruggisser, Sebastian; Riva, Francesco; Urbano, Alfredo
2016-07-01
In the presence of approximate global symmetries that forbid relevant interactions, strongly coupled light Dark Matter (DM) can appear weakly coupled at small-energy and generate a sizable relic abundance. Fundamental principles like unitarity restrict these symmetries to a small class, where the leading interactions are captured by effective operators up to dimension-8. Chiral symmetry, spontaneously broken global symmetries and non-linearly realized supersymmetry are examples of this. Their DM candidates (composite fermions, pseudo-Nambu-Goldstone Bosons and Goldstini) are interesting targets for LHC missing-energy searches.
Scalar strong interaction hadron theory
Hoh, Fang Chao
2015-01-01
The scalar strong interaction hadron theory, SSI, is a first principles' and nonlocal theory at quantum mechanical level that provides an alternative to low energy QCD and Higgs related part of the standard model. The quark-quark interaction is scalar rather than color-vectorial. A set of equations of motion for mesons and another set for baryons have been constructed. This book provides an account of the present state of a theory supposedly still at its early stage of development. This work will facilitate researchers interested in entering into this field and serve as a basis for possible future development of this theory.
Study of intermolecular interactions in binary mixtures of ethanol in methanol
Maharolkar, Aruna P.; Khirade, P. W.; Murugkar, A. G.
2016-05-01
Present paper deals with study of physicochemical properties like viscosity, density and refractive index for the binary mixtures of ethanol and methanol over the entire concentration range were measured at 298.15 K. The experimental data further used to determine the excess properties viz. excess molar volume, excess viscosity, excess molar refraction. The values of excess properties further fitted with Redlich-Kister (R-K Fit) equation to calculate the binary coefficients and standard deviation. The resulting excess parameters are used to indicate the presence of intermolecular interactions and strength of intermolecular interactions between the molecules in the binary mixtures. Excess parameters indicate structure making factor in the mixture predominates in the system.
Directory of Open Access Journals (Sweden)
Francisco Geraldo Barbosa
2015-12-01
Full Text Available Intermolecular forces are a useful concept that can explain the attraction between particulate matter as well as numerous phenomena in our lives such as viscosity, solubility, drug interactions, and dyeing of fibers. However, studies show that students have difficulty understanding this important concept, which has led us to develop a free educational software in English and Portuguese. The software can be used interactively by teachers and students, thus facilitating better understanding. Professors and students, both graduate and undergraduate, were questioned about the software quality and its intuitiveness of use, facility of navigation, and pedagogical application using a Likert scale. The results led to the conclusion that the developed computer application can be characterized as an auxiliary tool to assist teachers in their lectures and students in their learning process of intermolecular forces.
Czyznikowska, Z; Góra, R W; Zaleśny, R; Lipkowski, P; Jarzembska, K N; Dominiak, P M; Leszczynski, J
2010-07-29
A set of nearly 100 crystallographic structures was analyzed using ab initio methods in order to verify the effect of the conformational variability of Watson-Crick guanine-cytosine and adenine-thymine base pairs on the intermolecular interaction energy and its components. Furthermore, for the representative structures, a potential energy scan of the structural parameters describing mutual orientation of the base pairs was carried out. The results were obtained using the hybrid variational-perturbational interaction energy decomposition scheme. The electron correlation effects were estimated by means of the second-order Møller-Plesset perturbation theory and coupled clusters with singles and doubles method adopting AUG-cc-pVDZ basis set. Moreover, the characteristics of hydrogen bonds in complexes, mimicking those appearing in B-DNA, were evaluated using topological analysis of the electron density. Although the first-order electrostatic energy is usually the largest stabilizing component, it is canceled out by the associated exchange repulsion in majority of the studied crystallographic structures. Therefore, the analyzed complexes of the nucleic acid bases appeared to be stabilized mainly by the delocalization component of the intermolecular interaction energy which, in terms of symmetry adapted perturbation theory, encompasses the second- and higher-order induction and exchange-induction terms. Furthermore, it was found that the dispersion contribution, albeit much smaller in terms of magnitude, is also a vital stabilizing factor. It was also revealed that the intermolecular interaction energy and its components are strongly influenced by four (out of six) structural parameters describing mutual orientation of bases in Watson-Crick pairs, namely shear, stagger, stretch, and opening. Finally, as a part of a model study, much of the effort was devoted to an extensive testing of the UBDB databank. It was shown that the databank quite successfully reproduces the
Energy Technology Data Exchange (ETDEWEB)
Xantheas, Sotiris S.
2004-05-01
The modeling of the macroscopic properties of homogeneous and inhomogeneous systems via atomistic simulations such as molecular dynamics (MD) or Monte Carlo (MC) techniques is based on the accurate description of the relevant solvent-solute and solvent-solvent intermolecular interactions. The total energy (U) of an n-body molecular system can be formally written as [1,2,3
Directory of Open Access Journals (Sweden)
Cia-Hin Lau
2012-01-01
Full Text Available Epistasis (gene-gene interaction is a ubiquitous component of the genetic architecture of complex traits such as susceptibility to common human diseases. Given the strong negative correlation between circulating adiponectin and resistin levels, the potential intermolecular epistatic interactions between ADIPOQ (SNP+45T > G, SNP+276G > T, SNP+639T > C and SNP+1212A > G and RETN (SNP-420C > G and SNP+299G > A gene polymorphisms in the genetic risk underlying type 2 diabetes (T2DM and metabolic syndrome (MS were assessed. The potential mutual influence of the ADIPOQ and RETN genes on their adipokine levels was also examined. The rare homozygous genotype (risk alleles of SNP-420C > G at the RETN locus tended to be co-inherited together with the common homozygous genotypes (protective alleles of SNP+639T > C and SNP+1212A > G at the ADIPOQ locus. Despite the close structural relationship between the ADIPOQ and RETN genes, there was no evidence of an intermolecular epistatic interaction between these genes. There was also no reciprocal effect of the ADIPOQ and RETN genes on their adipokine levels, i.e., ADIPOQ did not affect resistin levels nor did RETN affect adiponectin levels. The possible influence of the ADIPOQ gene on RETN expression warrants further investigation.
Effective lagrangian for strong interactions
International Nuclear Information System (INIS)
Jain, P.
1988-01-01
We attempt to construct a realistic phenomenological Lagrangian in order to describe strong interactions. This is in general a very complicated problem and we shall explore its various aspects. We first include the vector mesons by writing down the most general chiral invariant terms proportional to the Levi-Civita symbol ε μναβ . These terms involve three unknown coefficients, which are calculated by using the experimental results of strong interaction processes. We then calculate the static nucleon properties by finding the solitonic excitations of this model. The results turn out to be, as is also the case for most other vector-pseudoscalar Lagrangians, better than the Skyrme model but are still somewhat different from the experiments. Another aspect that we shall study is the incorporation of scale anomaly of QCD into the Skyrme model. We thus introduce a scalar glueball in our Lagrangian. Here we find an interesting result that the effective glue field dynamically forms a bag for the soliton. Depending on the values of the parameters, we get either a deep bag or a shallow bag. However by including the scalar meson, we find that to get realistic scalar sector we must have the shallow bag. Finally we show some intriguing connections between the chiral quark model, in which the nucleon is described as a solitonic excitation, and the ordinary potential binding quark model
Sutton, Christopher; Risko, Chad; Bredas, Jean-Luc
2015-01-01
Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π
Yang, Fang-Ling; Yang, Xing; Wu, Rui-Zhi; Yan, Chao-Xian; Yang, Fan; Ye, Weichun; Zhang, Liang-Wei; Zhou, Pan-Pan
2018-04-25
The characters of σ- and π-holes of bromopentafluorobenzene (C6F5Br) enable it to interact with an electron-rich atom or group like pyridine which possesses an electron lone-pair N atom and a π ring. Theoretical studies of intermolecular interactions between C6F5Br and C5H5N have been carried out at the M06-2X/aug-cc-pVDZ level without and with the counterpoise method, together with single point calculations at M06-2X/TZVP, wB97-XD/aug-cc-pVDZ and CCSD(T)/aug-cc-pVDZ levels. The σ- and π-holes of C6F5Br exhibiting positive electrostatic potentials make these sites favorably interact with the N atom and the π ring of C5H5N with negative electrostatic potentials, leading to five different dimers connected by a σ-holen bond, a σ-holeπ bond or a π-holeπ bond. Their geometrical structures, characteristics, nature and spectroscopy behaviors were systematically investigated. EDA analyses reveal that the driving forces in these dimers are different. NCI, QTAIM and NBO analyses confirm the existence of intermolecular interactions formed via σ- and π-holes of C6F5Br and the N atom and the π ring of C5H5N. The experimental IR and Raman spectra gave us important information about the formation of molecular complexes between C6F5Br and C5H5N. We expect that the results could provide valuable insights into the investigation of intermolecular interactions involving σ- and π-holes.
Strongly interacting W's and Z's
International Nuclear Information System (INIS)
Gaillard, M.K.
1984-01-01
The study focussed primarily on the dynamics of a strongly interacting W, Z(SIW) sector, with the aim of sharpening predictions for total W, Z yield and W, Z multiplicities expected from WW fusion for various scenarios. Specific issues raised in the context of the general problem of modeling SIW included the specificity of the technicolor (or, equivalently, QCD) model, whether or not a composite scalar model can be evaded, and whether the standard model necessarily implies an I = J = O state (≅ Higgs particle) that is relatively ''light'' (M ≤ hundreds of TeV). The consensus on the last issue was that existing arguments are inconclusive. While the author shall briefly address compositeness and alternatives to the technicolor model, quantitative estimates will be of necessity based on technicolor or an extrapolation of pion data
Intermolecular Interactions between Eosin Y and Caffeine Using 1H-NMR Spectroscopy
Directory of Open Access Journals (Sweden)
Macduff O. Okuom
2013-01-01
Full Text Available DETECHIP has been used in testing analytes including caffeine, cocaine, and tetrahydrocannabinol (THC from marijuana, as well as date rape and club drugs such as flunitrazepam, gamma-hydroxybutyric acid (GHB, and methamphetamine. This study investigates the intermolecular interaction between DETECHIP sensor eosin Y (DC1 and the analyte (caffeine that is responsible for the fluorescence and color changes observed in the actual array. Using 1H-NMR, 1H-COSY, and 1H-DOSY NMR methods, a proton exchange from C-8 of caffeine to eosin Y is proposed.
The same number of optimized parameters scheme for determining intermolecular interaction energies
DEFF Research Database (Denmark)
Kristensen, Kasper; Ettenhuber, Patrick; Eriksen, Janus Juul
2015-01-01
We propose the Same Number Of Optimized Parameters (SNOOP) scheme as an alternative to the counterpoise method for treating basis set superposition errors in calculations of intermolecular interaction energies. The key point of the SNOOP scheme is to enforce that the number of optimized wave...... as numerically. Numerical results for second-order Møller-Plesset perturbation theory (MP2) and coupled-cluster with single, double, and approximate triple excitations (CCSD(T)) show that the SNOOP scheme in general outperforms the uncorrected and counterpoise approaches. Furthermore, we show that SNOOP...
Energy Technology Data Exchange (ETDEWEB)
Christensen, Anders S., E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu; Cui, Qiang, E-mail: andersx@chem.wisc.edu, E-mail: cui@chem.wisc.edu [Department of Chemistry, University of Wisconsin-Madison, 1101 University Ave., Madison, Wisconsin 53706 (United States); Elstner, Marcus [Theoretische Chemische Biologie, Universität Karlsruhe, Kaiserstr. 12, 76131 Karlsruhe (Germany)
2015-08-28
Semi-empirical quantum mechanical methods traditionally expand the electron density in a minimal, valence-only electron basis set. The minimal-basis approximation causes molecular polarization to be underestimated, and hence intermolecular interaction energies are also underestimated, especially for intermolecular interactions involving charged species. In this work, the third-order self-consistent charge density functional tight-binding method (DFTB3) is augmented with an auxiliary response density using the chemical-potential equalization (CPE) method and an empirical dispersion correction (D3). The parameters in the CPE and D3 models are fitted to high-level CCSD(T) reference interaction energies for a broad range of chemical species, as well as dipole moments calculated at the DFT level; the impact of including polarizabilities of molecules in the parameterization is also considered. Parameters for the elements H, C, N, O, and S are presented. The Root Mean Square Deviation (RMSD) interaction energy is improved from 6.07 kcal/mol to 1.49 kcal/mol for interactions with one charged species, whereas the RMSD is improved from 5.60 kcal/mol to 1.73 for a set of 9 salt bridges, compared to uncorrected DFTB3. For large water clusters and complexes that are dominated by dispersion interactions, the already satisfactory performance of the DFTB3-D3 model is retained; polarizabilities of neutral molecules are also notably improved. Overall, the CPE extension of DFTB3-D3 provides a more balanced description of different types of non-covalent interactions than Neglect of Diatomic Differential Overlap type of semi-empirical methods (e.g., PM6-D3H4) and PBE-D3 with modest basis sets.
Strongly interacting photons and atoms
International Nuclear Information System (INIS)
Alge, W.
1999-05-01
This thesis contains the main results of the research topics I have pursued during the my PhD studies at the University of Innsbruck and partly in collaboration with the Institut d' Optique in Orsay, France. It is divided into three parts. The first and largest part discusses the possibility of using strong standing waves as a tool to cool and trap neutral atoms in optical cavities. This is very important in the field of nonlinear optics where several successful experiments with cold atoms in cavities have been performed recently. A discussion of the optical parametric oscillator in a regime where the nonlinearity dominates the evolution is the topic of the second part. We investigated mainly the statistical properties of the cavity output of the three interactive cavity modes. Very recently a system has been proposed which promises fantastic properties. It should exhibit a giant Kerr nonlinearity with negligible absorption thus leading to a photonic turnstile device based on cold atoms in cavity. We have shown that this model suffers from overly simplistic assumptions and developed several more comprehensive approaches to study the behavior of this system. Apart from the division into three parts of different contents the thesis is divided into publications, supplements and invisible stuff. The intention of the supplements is to reach researchers which work in related areas and provide them with more detailed information about the concepts and the numerical tools we used. It is written especially for diploma and PhD students to give them a chance to use the third part of our work which is actually the largest one. They consist of a large number of computer programs we wrote to investigate the behavior of the systems in parameter regions where no hope exists to solve the equations analytically. (author)
Graphene-enhanced intermolecular interaction at interface between copper- and cobalt-phthalocyanines
Energy Technology Data Exchange (ETDEWEB)
Dou, Wei-Dong [Department of Physics, Shaoxing University, Shaoxing 312000 (China); Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Material Science, City University of Hong Kong, Hong Kong (China); Huang, Shu-Ping [Department of Chemistry, University of South Dakota, Vermillion, South Dakota 57069 (United States); Lee, Chun-Sing, E-mail: apcslee@cityu.edu.hk [Center of Super-Diamond and Advanced Films (COSDAF) and Department of Physics and Material Science, City University of Hong Kong, Hong Kong (China)
2015-10-07
Interfacial electronic structures of copper-phthalocyanine (CuPc), cobalt-phthalocyanine (CoPc), and graphene were investigated experimentally by using photoelectron spectroscopy. While the CuPc/graphene interface shows flat band structure and negligible interfacial dipole indicating quite weak molecule-substrate interaction, the CuPc/CoPc/graphene interface shows a large interfacial dipole and obvious energy level bending. Controlled experiments ruled out possible influences from the change in film structure of CuPc and pure π–π interaction between CoPc and CuPc. Analysis based on X-ray photoelectron spectroscopy and density functional theory reveals that the decrease in the work function for the CuPc/CoPc/graphene system is induced by the intermolecular interaction between CuPc and CoPc which is enhanced owning to the peculiar electronic properties at the CoPc-graphene interface.
Sutton, Christopher
2015-10-30
Noncovalent intermolecular interactions, which can be tuned through the toolbox of synthetic chemistry, determine not only the molecular packing but also the resulting electronic, optical, and mechanical properties of materials derived from π-conjugated molecules, oligomers, and polymers. Here, we provide an overview of the theoretical underpinnings of noncovalent intermolecular interactions and briefly discuss the computational chemistry approaches used to understand the magnitude of these interactions. These methodologies are then exploited to illustrate how noncovalent intermolecular interactions impact important electronic properties-such as the electronic coupling between adjacent molecules, a key parameter for charge-carrier transport-through a comparison between the prototype organic semiconductor pentacene with a series of N-substituted heteropentacenes. Incorporating an understanding of these interactions into the design of organic semiconductors can assist in developing novel materials systems from this fascinating molecular class. © 2015 American Chemical Society.
Energy Technology Data Exchange (ETDEWEB)
Güloğlu, Pınar; Acar, Nursel, E-mail: nursel.acar@ege.edu.tr
2016-10-20
Highlights: • Intermolecular interactions of pyrene with phenothiazine/promazine were investigated. • All investigated systems were optimized at ωB97XD/6-31G(d,p) level in gas phase. • The electronic transitions were determined using frontier orbitals. • Both Py–Pheno and Py–Prom are potential candidates for charge transfer systems. - Abstract: The intermolecular interactions between the pyrene (Py) (as acceptor) and phenothiazine (Pheno), promazine (Prom) (as donors) were investigated using UV/Vis absorption and fluorescence spectroscopy. Fluorescence quenching rate constants for Py–Pheno and Py–Prom systems have been calculated approximately 10{sup 10} M{sup −1} s{sup −1}, indicating diffusion controlled processes. A computational investigation has also been carried out in gas phase at ωB97XD/6-31G(d,p) level. Time-dependent density functional theory (TDDFT) was used to calculate the electronic transitions of molecules at B3LYP/6-311++G(d,p) level. Total electronic energies, complexation energies, free energy differences, excitation wavelengths, and HOMO–LUMO energy gaps are discussed in gas phase. Analyses of first excited singlet states have indicated charge transfers transitions between Py and Pheno, Prom through π–π stacking in gas phase at 433 nm and 466 nm, respectively. Due to its charge transfer character, Py–Pheno and Py–Prom systems seem to be appropriate models to investigate and design photosensitive materials.
Directory of Open Access Journals (Sweden)
Jiufang Duan
2015-01-01
Full Text Available A novel cellulose-chitosan gel was successfully prepared in three steps: (1 ferrocene- (Fc- cellulose with degrees of substitution (DS of 0.5 wt% was synthesised by ferrocenecarboxylic acid and cellulose within dimethylacetamide/lithium chloride (DMAc/LiCl; (2 the β-cyclodextrin (β-CD groups were introduced onto the chitosan chains by reacting chitosan with epichlorohydrin in dimethyl sulphoxide and a DS of 0.35 wt%; (3 thus, the cellulose-chitosan gel was obtained via an intermolecular inclusion interaction of Fc-cellulose and β-CD-chitosan in DMA/LiCl, that is, by an intermolecular inclusion interaction, between the Fc groups of cellulose and the β-CD groups on the chitosan backbone at room temperature. The successful synthesis of Fc-cellulose and β-CD-chitosan was characterised by 13C-NMR spectroscopy. The gel based on β-CD-chitosan and Fc-cellulose was formed under mild conditions which can engender autonomous healing between cut surfaces after 24 hours: the gel cannot self-heal while the cut surfaces were coated with a solution of a competitive guest (adamantane acid. The cellulose-chitosan complex made by this method underwent self-healing. Therefore, this study provided a novel method of expanding the application of chitosan by binding it with another polymer.
Energy Technology Data Exchange (ETDEWEB)
Chavda, Bhavin R., E-mail: chavdabhavin9@gmail.com; Dubey, Rahul P.; Patel, Urmila H. [Department of Physics, Sardar Patel University, Vallabh Vidyanagar-388120, Gujarat (India); Gandhi, Sahaj A. [Bhavan’s Shri I.L. Pandya Arts-Science and Smt. J.M. shah Commerce College, Dakar, Anand -388001, Gujarat, Indian (India); Barot, Vijay M. [P. G. Center in Chemistry, Smt. S. M. Panchal Science College, Talod, Gujarat 383 215 (India)
2016-05-06
The novel chalcone derivatives have widespread applications in material science and medicinal industries. The density functional theory (DFT) is used to optimized the molecular structure of the three chalcone derivatives (M-I, II, III). The observed discrepancies between the theoretical and experimental (X-ray data) results attributed to different environments of the molecules, the experimental values are of the molecule in solid state there by subjected to the intermolecular forces, like non-bonded hydrogen bond interactions, where as isolated state in gas phase for theoretical studies. The lattice energy of all the molecules have been calculated using PIXELC module in Coulomb –London –Pauli (CLP) package and is partitioned into corresponding coulombic, polarization, dispersion and repulsion contributions. Lattice energy data confirm and strengthen the finding of the X-ray results that the weak but significant intermolecular interactions like C-H…O, Π- Π and C-H… Π plays an important role in the stabilization of crystal packing.
International Nuclear Information System (INIS)
Machida, S; Hirai, H; Kawamura, T; Yamamoto, Y; Yagi, T
2010-01-01
High-pressure experiments of hydrogen hydrate were performed using a diamond anvil cell under conditions of 0.1-44.2 GPa and at room temperature. Also, high pressure Raman studies of solid hydrogen were performed in the pressure range of 0.1-43.7 GPa. X-ray diffractometry (XRD) for hydrogen hydrate revealed that a known high-pressure structure, filled ice Ic structure, of hydrogen hydrate transformed to a new high-pressure structure at approximately 35-40 GPa. A comparison of the Raman spectroscopy of a vibron for hydrogen molecules between hydrogen hydrate and solid hydrogen revealed that the extraction of hydrogen molecules from hydrogen hydrate occurred above 20 GPa. Also, the Raman spectra of a roton revealed that the rotation of hydrogen molecules in hydrogen hydrate was suppressed at around 20 GPa and that the rotation recovered under higher pressure. These results indicated that remarkable intermolecular interactions in hydrogen hydrate between neighboring hydrogen molecules and between guest hydrogen molecules and host water molecules might occur. These intermolecular interactions could produce the stability of hydrogen hydrate.
Directory of Open Access Journals (Sweden)
O. V. Vashchenko
2016-07-01
Full Text Available Intermolecular interactions between decamethoxinum (DEC and acetylsalicylic acid (ASА have been studied in the phospholipid-containing systems of escalating complexity levels. The host media for these substances were solvents, L-α-dipalmitoylphosphatidylcholine (DPPC membranes, and samples of human erythrocytes. Peculiar effects caused by DEC-ASА interaction have been observed in each system using appropriate techniques: (a DEC-ASА non-covalent complexes formation in DPPC-containing systems were revealed by mass spectrometry with electrospray ionization; (b joint DEC-ASА action on DPPC model membranes led to increasing of membrane melting temperature Tm, whereas individual drugs caused pronounced Tm decreasing, which was demonstrated by differential scanning calorimetry; (c deceleration of DEC-induced haemolysis of erythrocytes under joint DEC-ASА application was observed by optical microscopy.
INS study of intermolecular interaction at the silicone-fumed silica interface
International Nuclear Information System (INIS)
Sheka, E.F.; Natkaniec, I.
1999-01-01
Complete text of publication follows. The paper presents results related to the interface formed between finned silica particles and polydimethylsiloxane polymers, presented in the study by a five-member cyclic oligomer SiS. The substrate surface is terminated by either hydroxyl units or by trimethylsiloxy ones. When the interface is formed, methyl units are the main constituents providing neutron scattering. Protium/deuterium exchange has been used to distinguish the latter belonging to either adsorbate or substrate. A detailed analysis of the intermolecular interaction impact on both adsorbed molecule and substrate has been performed. The observed features are supported by the vibrational spectra calculations performed on the basis of a modem quantum-chemical approach and supplemented by the solution of the inverse spectral problem. (author)
DEFF Research Database (Denmark)
Hanni, Matti; Lantto, Perttu; Ilias, Miroslav
2007-01-01
Relativistic effects on the 129Xe nuclear magnetic resonance shielding and 131Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe2 system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular...... interaction-induced binary chemical shift d, the anisotropy of the shielding tensor ?s, and the NQC constant along the internuclear axis ?ll are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full...... is obtained for d and ?s in Xe2. For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other...
International Nuclear Information System (INIS)
Karayel, A.; Özbey, S.; Ayhan-Kılcıgil, G.; Kuş, C.
2015-01-01
The crystal structures of 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(3-fluorophenyl)-2, 4-dihydro-[1,2,4]-triazole-3-thione (G6C) and 5-(2-(p-chlorophenylbenzimidazol-1-yl-methyl)-4-(2-methylphenyl)-2, 4-dihydro-[1,2,4]-triazole-3-thione (G4C) have been determined by single-crystal X-ray diffraction. Benzimidazole ring systems in both molecules are planar. The triazole part is almost perpendicular to the phenyl and the benzimidazole parts of the molecules in order to avoid steric interactions between the rings. The crystal structures are stabilized by intermolecular hydrogen bonds between the amino group of the triazole and the nitrogen atom of benzimidazole of a neighboring molecule
Strong interactions in low dimensions
Baeriswyl, D
2007-01-01
This book provides an attempt to convey the colorful facets of condensed matter systems with reduced dimensionality. Some of the specific features predicted for interacting one-dimensional electron systems, such as charge- and spin-density waves, have been observed in many quasi-one-dimensional materials. The two-dimensional world is even richer: besides d-wave superconductivity and the Quantum Hall Effect - perhaps the most spectacular phases explored during the last two decades - many collective charge and spin states have captured the interest of researchers, such as charge stripes or spont
Zhou, Kai-Li; Pan, Dong-Qi; Lou, Yan-Yue; Shi, Jie-Hua
2018-04-16
The intermolecular interaction of fosinopril, an angiotensin converting enzyme inhibitor with bovine serum albumin (BSA), has been investigated in physiological buffer (pH 7.4) by multi-spectroscopic methods and molecular docking technique. The results obtained from fluorescence and UV absorption spectroscopy revealed that the fluorescence quenching mechanism of BSA induced by fosinopril was mediated by the combined dynamic and static quenching, and the static quenching was dominant in this system. The binding constant, K b , value was found to lie between 2.69 × 10 3 and 9.55 × 10 3 M -1 at experimental temperatures (293, 298, 303, and 308 K), implying the low or intermediate binding affinity between fosinopril and BSA. Competitive binding experiments with site markers (phenylbutazone and diazepam) suggested that fosinopril preferentially bound to the site I in sub-domain IIA on BSA, as evidenced by molecular docking analysis. The negative sign for enthalpy change (ΔH 0 ) and entropy change (ΔS 0 ) indicated that van der Waals force and hydrogen bonds played important roles in the fosinopril-BSA interaction, and 8-anilino-1-naphthalenesulfonate binding assay experiments offered evidence of the involvements of hydrophobic interactions. Moreover, spectroscopic results (synchronous fluorescence, 3-dimensional fluorescence, and Fourier transform infrared spectroscopy) indicated a slight conformational change in BSA upon fosinopril interaction. Copyright © 2018 John Wiley & Sons, Ltd.
Remnants of strong tidal interactions
International Nuclear Information System (INIS)
Mcglynn, T.A.
1990-01-01
This paper examines the properties of stellar systems that have recently undergone a strong tidal shock, i.e., a shock which removes a significant fraction of the particles in the system, and where the shocked system has a much smaller mass than the producer of the tidal field. N-body calculations of King models shocked in a variety of ways are performed, and the consequences of the shocks are investigated. The results confirm the prediction of Jaffe for shocked systems. Several models are also run where the tidal forces on the system are constant, simulating a circular orbit around a primary, and the development of tidal radii under these static conditions appears to be a mild process which does not dramatically affect material that is not stripped. The tidal radii are about twice as large as classical formulas would predict. Remnant density profiles are compared with a sample of elliptical galaxies, and the implications of the results for the development of stellar populations and galaxies are considered. 38 refs
Zhang, Rui; Guo, Jing; Liu, Yuanfa; Chen, Shuang; Zhang, Sen; Yu, Yue
2018-06-01
Sodium alginate (SA) and antarctic krill protein (AKP) were blended to fabricate the SA/AKP composite fibers by the conventional wet spinning method using 5% CaCl 2 as coagulation solution. The sodium salt was added to the SA/AKP solution to adjust the ionization degree and intermolecular interaction of composite system. The main purpose of this study is to investigate the influences of sodium salt types (NaCl, CH 3 COONa, Na 2 SO 4 ) on the intermolecular interaction of SA/AKP composite fibers. The intermolecular interaction, morphology, crystallinity, thermal stability and mechanical properties of SA/AKP composite fibers were analyzed by fourier transform infrared spectroscopy (FT-IR), scanning electron microscope (SEM), x-ray diffraction (XRD), thermogravimetric analysis (TGA). The results show that the types of sodium salt have obvious influences on the content of both β-sheet, intermolecular hydrogen bond, breaking strength and surface morphology in SA/AKP composite fibers, but have a negligible effect on the crystallinity and thermal stability. Copyright © 2018 Elsevier Ltd. All rights reserved.
Karabulut, Sedat; Namli, Hilmi; Kurtaran, Raif; Yildirim, Leyla Tatar; Leszczynski, Jerzy
2014-03-01
The title compound, N-3-hydroxyphenyl-4-methoxybenzamide (3) was prepared by the acylation reaction of 3-aminophenol (1) and 4-metoxybenzoylchloride (2) in THF and characterized by ¹H NMR, ¹³C NMR and elemental analysis. Molecular structure of the crystal was determined by single crystal X-ray diffraction and DFT calculations. 3 crystallizes in monoclinic P2₁/c space group. The influence of intermolecular interactions (dimerization and crystal packing) on molecular geometry has been evaluated by calculations performed for three different models; monomer (3), dimer (4) and dimer with added unit cell contacts (5). Molecular structure of 3, 4 and 5 was optimized by applying B3LYP method with 6-31G+(d,p) basis set in gas phase and compared with X-ray crystallographic data including bond lengths, bond angles and selected dihedral angles. It has been concluded that although the crystal packing and dimerization have a minor effect on bond lengths and angles, however, these interactions are important for the dihedral angles and the rotational conformation of aromatic rings. Copyright © 2013 Elsevier Inc. All rights reserved.
Chu, Zonglin; Han, Yanxiao; Kral, Petr; Klajn, Rafal
2018-04-19
Confining organic molecules to the surfaces of inorganic nanoparticles can induce intermolecular interactions between them, which can affect the composition of the mixed self-assembled monolayers obtained by co-adsorption from solution of two different molecules. Here, we study co-adsorption of two thiolated ligands-a dialkylviologen and a zwitterionic sulfobetaine-that can interact with each other electrostatically, onto gold nanoparticles. Consequently, the nanoparticles favor a narrow range of ratios of these two molecules that is largely independent of the molar ratio in solution. We show that changing the solution molar ratio of two ligands by a factor of ~5,000 affects the on-nanoparticle ratio of these ligands by only 3 times. This behavior is reminiscent of the formation of insoluble inorganic salts (e.g., AgCl), which similarly compensate positive and negative charges upon crystallizing. Our results pave the way towards developing well-defined hybrid organic-inorganic nanostructures. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Physics challenges in the strong interactions
International Nuclear Information System (INIS)
Ellis, S.D.
1992-01-01
The study of strong interactions is now a mature field for which scientist now know that the correct underlying theory is QCD. Here, an overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders
Physics challenges in the strong interactions
Energy Technology Data Exchange (ETDEWEB)
Ellis, S.D. [Univ. of Washington, Seattle (United States)
1992-12-31
The study of strong interactions is now a mature field for which scientist now know that the correct underlying theory is QCD. Here, an overview of the challenges to be faced in the area of the strong interactions during the 1990`s is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.
Christensen, Anders S; Kromann, Jimmy C; Jensen, Jan H; Cui, Qiang
2017-10-28
To facilitate further development of approximate quantum mechanical methods for condensed phase applications, we present a new benchmark dataset of intermolecular interaction energies in the solution phase for a set of 15 dimers, each containing one charged monomer. The reference interaction energy in solution is computed via a thermodynamic cycle that integrates dimer binding energy in the gas phase at the coupled cluster level and solute-solvent interaction with density functional theory; the estimated uncertainty of such calculated interaction energy is ±1.5 kcal/mol. The dataset is used to benchmark the performance of a set of semi-empirical quantum mechanical (SQM) methods that include DFTB3-D3, DFTB3/CPE-D3, OM2-D3, PM6-D3, PM6-D3H+, and PM7 as well as the HF-3c method. We find that while all tested SQM methods tend to underestimate binding energies in the gas phase with a root-mean-squared error (RMSE) of 2-5 kcal/mol, they overestimate binding energies in the solution phase with an RMSE of 3-4 kcal/mol, with the exception of DFTB3/CPE-D3 and OM2-D3, for which the systematic deviation is less pronounced. In addition, we find that HF-3c systematically overestimates binding energies in both gas and solution phases. As most approximate QM methods are parametrized and evaluated using data measured or calculated in the gas phase, the dataset represents an important first step toward calibrating QM based methods for application in the condensed phase where polarization and exchange repulsion need to be treated in a balanced fashion.
Christensen, Anders S.; Kromann, Jimmy C.; Jensen, Jan H.; Cui, Qiang
2017-10-01
To facilitate further development of approximate quantum mechanical methods for condensed phase applications, we present a new benchmark dataset of intermolecular interaction energies in the solution phase for a set of 15 dimers, each containing one charged monomer. The reference interaction energy in solution is computed via a thermodynamic cycle that integrates dimer binding energy in the gas phase at the coupled cluster level and solute-solvent interaction with density functional theory; the estimated uncertainty of such calculated interaction energy is ±1.5 kcal/mol. The dataset is used to benchmark the performance of a set of semi-empirical quantum mechanical (SQM) methods that include DFTB3-D3, DFTB3/CPE-D3, OM2-D3, PM6-D3, PM6-D3H+, and PM7 as well as the HF-3c method. We find that while all tested SQM methods tend to underestimate binding energies in the gas phase with a root-mean-squared error (RMSE) of 2-5 kcal/mol, they overestimate binding energies in the solution phase with an RMSE of 3-4 kcal/mol, with the exception of DFTB3/CPE-D3 and OM2-D3, for which the systematic deviation is less pronounced. In addition, we find that HF-3c systematically overestimates binding energies in both gas and solution phases. As most approximate QM methods are parametrized and evaluated using data measured or calculated in the gas phase, the dataset represents an important first step toward calibrating QM based methods for application in the condensed phase where polarization and exchange repulsion need to be treated in a balanced fashion.
Algebra of strong and electroweak interactions
International Nuclear Information System (INIS)
Bolokhov, S.V.; Vladimirov, Yu.S.
2004-01-01
The algebraic approach to describing the electroweak and strong interactions is considered within the frames of the binary geometrophysics, based on the principles of the Fokker-Feynman direct interparticle interaction theories of the Kaluza-Klein multidimensional geometrical models and the physical structures theory. It is shown that in this approach the electroweak and strong elementary particles interaction through the intermediate vector bosons, are characterized by the subtypes of the algebraic classification of the complex 3 x 3-matrices [ru
Intermolecular Interactions in the TMEM16A Dimer Controlling Channel Activity.
Scudieri, Paolo; Musante, Ilaria; Gianotti, Ambra; Moran, Oscar; Galietta, Luis J V
2016-12-08
TMEM16A and TMEM16B are plasma membrane proteins with Ca 2+ -dependent Cl - channel function. By replacing the carboxy-terminus of TMEM16A with the equivalent region of TMEM16B, we obtained channels with potentiation of channel activity. Progressive shortening of the chimeric region restricted the "activating domain" to a short sequence close to the last transmembrane domain and led to TMEM16A channels with high activity at very low intracellular Ca 2+ concentrations. To elucidate the molecular mechanism underlying this effect, we carried out experiments based on double chimeras, Forster resonance energy transfer, and intermolecular cross-linking. We also modeled TMEM16A structure using the Nectria haematococca TMEM16 protein as template. Our results indicate that the enhanced activity in chimeric channels is due to altered interaction between the carboxy-terminus and the first intracellular loop in the TMEM16A homo-dimer. Mimicking this perturbation with a small molecule could be the basis for a pharmacological stimulation of TMEM16A-dependent Cl - transport.
Energy Technology Data Exchange (ETDEWEB)
Subbotin, O.; Belosludov, V.; Adamova, T. [Russian Academy of Science, Novosibirsk (Russian Federation). Nikolaev Inst. of Inorganic Chemistry; Belosludov, R.; Kawazoe, Y. [Tohoku Univ., Aoba-ku, Sendai (Japan). Inst. for Materials Research; Kudoh, J.I. [Tohoku Univ., Aoba-ku, Sendai (Japan). Center for Northeast Asia Studies
2008-07-01
This paper presented a newly developed method to accurately predict the thermodynamic properties of clathrate hydrates, particularly their structural phase transitions under pressure. The method is based on the theory of Van-der-Waals and Platteeuw with some modifications that include the influence of guest molecules on the host lattice. The model was used to explain the exception from the established rule that small guest molecules form structure s1 and large molecules form structure s2 hydrates. In this study, the thermodynamic properties of argon (Ar) hydrate and methane hydrate, each in both cubic structure s1 and s2 were modelled. The model showed that two competing factors play a role in the formation of inclusions, notably the intermolecular interaction of guest molecules with water molecules, and the configuration entropy. Competition of these 2 factors determines the structure of hydrate formed at different pressures. The model provides an accurate description of the thermodynamic properties of gas hydrates and how they behave under pressure. For the argon hydrates, the structural phase transition from structure s2 to s1 at high pressure was predicted, while methane hydrates were predicted to be metastable in the s2 structure. The model can be used for other inclusion compounds with the same type of composition such as clathrate silicon, zeolites, and inclusion compounds of semiconductor elements. 17 refs., 5 figs.
Directory of Open Access Journals (Sweden)
Konczak L
2016-11-01
Full Text Available Lukasz Konczak,1 Jolanta Narkiewicz-Michalek,2 Giorgia Pastorin,3 Tomasz Panczyk1 1Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, Cracow, 2Department of Chemistry, Maria Curie-Sklodowska University, Lublin, Poland; 3Department of Pharmacy, National University of Singapore, Singapore Abstract: This work deals with the role of intermolecular interactions in the stability of a carbon nanotube (CNT capped by functionalized gold nanoparticles (AuNPs. The importance of such a system is due to its potential application as a pH-controlled drug carrier. Our preliminary experimental studies showed that fabrication of such a nanobottle/nanocontainer is feasible and it is possible to encapsulate the anticancer drug cisplatin inside the inner space of a CNT and seal its ends by functionalized AuNPs. The expected behavior, that is, detachment of AuNPs at acidic pH and the release of cisplatin, was, however, not observed. On the other hand, our theoretical studies of chemically identical system led to the conclusion that the release of cisplatin at acidic pH should be observed. Therefore, in this work, a deeper theoretical analysis of various factors that could be responsible for the disagreement between experimental and theoretical results were performed. The study found that the major factor is a large dispersion interaction component acting between CNT and AuNP in solution in the case of the experimental system. This factor can be controlled to some extent by tuning the system size or the ratio between AuNP diameter and CNT diameter. Thus, such kind of a pH-sensitive drug carrier is still of great interest, but its structural parameters need to be properly adjusted. Keywords: hydrazone bond, drug delivery, dispersion interactions, cisplatin, acidic pH
Pan, Xiaoyong; Chen, Hui; Wang, Wei Zhi; Ng, Siu Choon; Chan-Park, Mary B
2011-07-21
This paper explores evidence of an optically mediated interaction that is active in the separation mechanism of certain selective agents through consideration of the contrasting selective behaviors of two conjugated polymers with distinct optical properties. The involvement of a RET-induced intermolecular pairing force is implied by the different illumination response behaviors. The magnitude of this interaction scales with the external stimulus parameter, the illumination irradiance (I), and thus is tunable. This suggests a facile technique to modify the selectivity of polymers toward specific SWNT species by altering the polymer structure to adjust the corresponding intermolecular interaction. This is the first experimental verification and application of a RET-induced intermolecular pairing force to SWNT separation. With this kind of interaction taken into account, reasonable interpretation of some conflicting data, especially PLE maps, can be easily made. The above conclusion can be applied to other substances as long as they are electrically neutral and there is photon-induced RET between them. The significant magnitude of this interaction makes direct manipulation of molecules/particles possible and is expected to have applications in molecular engineering. © 2011 American Chemical Society
Physics challenges in the strong interactions
Energy Technology Data Exchange (ETDEWEB)
Ellis, S.D.
1991-01-01
An overview of the challenges to be faced in the area of the strong interactions during the 1990`s is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.
Physics challenges in the strong interactions
International Nuclear Information System (INIS)
Ellis, S.D.
1991-01-01
An overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders
Strong interaction effects in hadronic atoms
International Nuclear Information System (INIS)
Kaufmann, W.B.
1977-01-01
The WKB method is applied to the calculation of strong interaction-induced level widths and shifts of hadronic atoms. The calculation, while elementary enough for undergraduate quantum mechanics students, gives a good account of kaonic and antiprotonic atom data
The Charm and Beauty of Strong Interactions
El-Bennich, Bruno
2018-01-01
We briefly review common features and overlapping issues in hadron and flavor physics focussing on continuum QCD approaches to heavy bound states, their mass spectrum and weak decay constants in different strong interaction models.
Sangeetha, K.; Kumar, V. R. Suresh; Marchewka, M. K.; Binoy, J.
2018-05-01
Since, the intermolecular interactions play a crucial role in the formation of crystalline network, its analysis throws light on structure dependent crystalline properties. In the present study, DFT based vibrational spectral investigation has been performed in the stretching region (3500 cm-1 - 2800 cm-1) of IR and Raman spectra of melaminium chloride hemihydrates. The intermolecular interaction has been investigated by analyzing the half width of the OH and NH stretching profile of the deconvoluted spectra. Correlation of vibrational spectra with Hirshfeld surface analysis and finger print plot has been contemplated and molecular docking studies has been performed on melaminium chloride hemihydrate to assess its role in the drug transport mechanism and toxicity to human body.
Energy Technology Data Exchange (ETDEWEB)
Azar, Richard Julian, E-mail: julianazar2323@berkeley.edu; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California and Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2015-05-28
Your correspondents develop and apply fully nonorthogonal, local-reference perturbation theories describing non-covalent interactions. Our formulations are based on a Löwdin partitioning of the similarity-transformed Hamiltonian into a zeroth-order intramonomer piece (taking local CCSD solutions as its zeroth-order eigenfunction) plus a first-order piece coupling the fragments. If considerations are limited to a single molecule, the proposed intermolecular similarity-transformed perturbation theory represents a frozen-orbital variant of the “(2)”-type theories shown to be competitive with CCSD(T) and of similar cost if all terms are retained. Different restrictions on the zeroth- and first-order amplitudes are explored in the context of large-computation tractability and elucidation of non-local effects in the space of singles and doubles. To accurately approximate CCSD intermolecular interaction energies, a quadratically growing number of variables must be included at zeroth-order.
Dual field theory of strong interactions
International Nuclear Information System (INIS)
Akers, D.
1987-01-01
A dual field theory of strong interactions is derived from a Lagrangian of the Yang-Mills and Higgs fields. The existence of a magnetic monopole of mass 2397 MeV and Dirac charge g = (137/2)e is incorporated into the theory. Unification of the strong, weak, and electromagnetic forces is shown to converge at the mass of the intermediate vector boson W/sup +/-/. The coupling constants of the strong and weak interactions are derived in terms of the fine-structure constant α = 1/137
Wang, Yi-Siang; Yin, Chih-Chien; Chao, Sheng D
2014-10-07
We perform an ab initio computational study of molecular complexes with the general formula CF3X-B that involve one trifluorohalomethane CF3X (X = Cl or Br) and one of a series of Lewis bases B in the gas phase. The Lewis bases are so chosen that they provide a range of electron-donating abilities for comparison. Based on the characteristics of their electron pairs, we consider the Lewis bases with a single n-pair (NH3 and PH3), two n-pairs (H2O and H2S), two n-pairs with an unsaturated bond (H2CO and H2CS), and a single π-pair (C2H4) and two π-pairs (C2H2). The aim is to systematically investigate the influence of the electron pair characteristics and the central atom substitution effects on the geometries and energetics of the formed complexes. The counterpoise-corrected supermolecule MP2 and coupled-cluster single double with perturbative triple [CCSD(T)] levels of theory have been employed, together with a series of basis sets up to aug-cc-pVTZ. The angular and radial configurations, the binding energies, and the electrostatic potentials of the stable complexes have been compared and discussed as the Lewis base varies. For those complexes where halogen bonding plays a significant role, the calculated geometries and energetics are consistent with the σ-hole model. Upon formation of stable complexes, the C-X bond lengths shorten, while the C-X vibrational frequencies increase, thus rendering blueshifting halogen bonds. The central atom substitution usually enlarges the intermolecular bond distances while it reduces the net charge transfers, thus weakening the bond strengths. The analysis based on the σ-hole model is grossly reliable but requires suitable modifications incorporating the central atom substitution effects, in particular, when interaction components other than electrostatic contributions are involved.
International Nuclear Information System (INIS)
Gelbart, W.M.
1980-01-01
In this article some of the theoretical background is presented for the following papers on 'Intermolecular Spectroscopy and Dynamical Properties of Dense Systems'. In Section 1 we outline a simple semi-classical description of the interaction between optical radiation and matter. The motion of a many-body polarizability is introduced; limiting forms of this complicated quantity lead to the familiar cases of light scattering spectra. In Section 2 we consider the linear response approximation, and the equation of motion for the many-body density matrix is solved to first order in the matter-radiation interaction. The often quoted fluctuation-dissipation theorem and the time-dependent, equilibrium correlation functions are discussed. Section 3 treats the problem of the local field. In Section 4 we consider the special case of collision-induced light scattering by atomic fluids in the low-density limit. This allows us to focus on determining the interaction polarizability for simple gases. Finally, in Section 5 we distinguish between collision-induced and multiple light scattering, and discuss the double-light-scattering analyses which provide new information about critical and thermodynamically unstable fluids. (KBE)
Zhang, Zhaoyang; Li, Shihui; Chen, Niancao; Yang, Cheng; Wang, Yong
2013-04-08
Extensive studies have been recently carried out to achieve dynamic control of cell-material interactions primarily through physicochemical stimulation. The purpose of this study was to apply reversible intermolecular hybridization to program cell-hydrogel interactions in physiological conditions based on DNA-antibody chimeras and complementary oligonucleotides. The results showed that DNA oligonucleotides could be captured to and released from the immobilizing DNA-functionalized hydrogels with high specificity via DNA hybridization. Accordingly, DNA-antibody chimeras were captured to the hydrogels, successfully inducing specific cell attachment. The cell attachment to the hydrogels reached the plateau at approximately half an hour after the functionalized hydrogels and the cells were incubated together. The attached cells were rapidly released from the bound hydrogels when triggering complementary oligonucleotides were introduced to the system. However, the capability of the triggering complementary oligonucleotides in releasing cells was affected by the length of intermolecular hybridization. The length needed to be at least more than 20 base pairs in the current experimental setting. Notably, because the procedure of intermolecular hybridization did not involve any harsh condition, the released cells maintained the same viability as that of the cultured cells. The functionalized hydrogels also exhibited the potential to catch and release cells repeatedly. Therefore, this study demonstrates that it is promising to regulate cell-material interactions dynamically through the DNA-programmed display of DNA-protein chimeras.
Sutton, Christopher
2015-06-15
Rubrene is one of the most studied molecular semiconductors; its chemical structure consists of a tetracene backbone with four phenyl rings appended to the two central fused rings. Derivatization of these phenyl rings can lead to two very different solid-state molecular conformations and packings: One in which the tetracene core is planar and there exists substantive overlap among neighboring π-conjugated backbones; and another where the tetracene core is twisted and the overlap of neighboring π-conjugated backbones is completely disrupted. State-of-the-art electronic-structure calculations show for all isolated rubrene derivatives that the twisted conformation is more favorable (by -1.7 to -4.1 kcal mol-1), which is a consequence of energetically unfavorable exchange-repulsion interactions among the phenyl side groups. Calculations based on available crystallographic structures reveal that planar conformations of the tetracene core in the solid state result from intermolecular interactions that can be tuned through well-chosen functionalization of the phenyl side groups, and lead to improved intermolecular electronic couplings. Understanding the interplay of these intramolecular and intermolecular interactions provides insight into how to chemically modify rubrene and similar molecular semiconductors to improve the intrinsic materials electronic properties.
A theory of the strong interactions
International Nuclear Information System (INIS)
Gross, D.J.
1979-01-01
The most promising candidate for a fundamental microscopic theory of the strong interactions is a gauge theory of colored quarks-Quantum Chromodynamics (QCD). There are many excellent reasons for believing in this theory. It embodies the broken symmetries, SU(3) and chiral SU(3)xSU(3), of the strong interactions and reflects the success of (albeit crude) quark models in explaining the spectrum of the observed hadrons. The hidden quantum number of color, necessary to account for the quantum numbers of the low lying hadrons, plays a fundamental role in this theory as the SU(3) color gauge vector 'gluons' are the mediators of the strong interactions. The absence of physical quark states can be 'explained' by the hypothesis of color confinement i.e. that hadrons are permanently bound in color singlet bound states. Finally this theory is unique in being asymptotically free, thus accounting for the almost free field theory behvior of quarks observed at short distances. (Auth.)
Interaction of strong electromagnetic fields with atoms
International Nuclear Information System (INIS)
Brandi, H.S.; Davidovich, L.; Zagury, N.
1982-06-01
Several non-linear processes involvoing the interaction of atoms with strong laser fields are discussed, with particular emphasis on the ionization problem. Non-perturbative methods which have been proposed to tackle this problem are analysed, and shown to correspond to an expansion in the intra-atomic potential. The relation between tunneling and multiphoton absorption as ionization mechanisms, and the generalization of Einstein's photoelectric equation to the strong-field case are discussed. (Author) [pt
Hanni, Matti; Lantto, Perttu; Ilias, Miroslav; Jensen, Hans Jorgen Aagaard; Vaara, Juha
2007-10-28
Relativistic effects on the (129)Xe nuclear magnetic resonance shielding and (131)Xe nuclear quadrupole coupling (NQC) tensors are examined in the weakly bound Xe(2) system at different levels of theory including the relativistic four-component Dirac-Hartree-Fock (DHF) method. The intermolecular interaction-induced binary chemical shift delta, the anisotropy of the shielding tensor Deltasigma, and the NQC constant along the internuclear axis chi( parallel) are calculated as a function of the internuclear distance. DHF shielding calculations are carried out using gauge-including atomic orbitals. For comparison, the full leading-order one-electron Breit-Pauli perturbation theory (BPPT) is applied using a common gauge origin. Electron correlation effects are studied at the nonrelativistic (NR) coupled-cluster singles and doubles with perturbational triples [CCSD(T)] level of theory. The fully relativistic second-order Moller-Plesset many-body perturbation (DMP2) theory is used to examine the cross coupling between correlation and relativity on NQC. The same is investigated for delta and Deltasigma by BPPT with a density functional theory model. A semiquantitative agreement between the BPPT and DHF binary property curves is obtained for delta and Deltasigma in Xe(2). For these properties, the currently most complete theoretical description is obtained by a piecewise approximation where the uncorrelated relativistic DHF results obtained close to the basis-set limit are corrected, on the one hand, for NR correlation effects and, on the other hand, for the BPPT-based cross coupling of relativity and correlation. For chi( parallel), the fully relativistic DMP2 results obtain a correction for NR correlation effects beyond MP2. The computed temperature dependence of the second virial coefficient of the (129)Xe nuclear shielding is compared to experiment in Xe gas. Our best results, obtained with the piecewise approximation for the binary chemical shift combined with the
Mu, Zhongcheng; Shao, Qi; Ye, Jun; Zeng, Zebing; Zhao, Yang; Hng, Huey Hoon; Boey, Freddy Yin Chiang; Wu, Jishan; Chen, Xiaodong
2011-02-15
Two-dimensional (2D) supramolecular assemblies of a series of novel C(3)-symmetric hexa-peri-hexabenzocoronene (HBC) derivatives bearing different substituents adsorbed on highly oriented pyrolytic graphite were studied by using scanning tunneling microscopy at a solid-liquid interface. It was found that the intermolecular dipole-dipole interactions play a critical role in controlling the interfacial supramolecular assembly of these C(3)-symmetric HBC derivatives at the solid-liquid interface. The HBC molecule bearing three -CF(3) groups could form 2D honeycomb structures because of antiparallel dipole-dipole interactions, whereas HBC molecules bearing three -CN or -NO(2) groups could form hexagonal superstructures because of a special trimeric arrangement induced by dipole-dipole interactions and weak hydrogen bonding interactions ([C-H···NC-] or [C-H···O(2)N-]). Molecular mechanics and dynamics simulations were performed to reveal the physics behind the 2D structures as well as detailed functional group interactions. This work provides an example of how intermolecular dipole-dipole interactions could enable fine control over the self-assembly of disklike π-conjugated molecules.
Physics challenges in the strong interactions
Energy Technology Data Exchange (ETDEWEB)
Ellis, S.D.
1991-01-01
An overview of the challenges to be faced in the area of the strong interactions during the 1990's is presented. As an illustrative example special attention is given to the analysis of jets as studied at hadron colliders.
Bouzková, Kateřina; Babinský, Martin; Novosadová, Lucie; Marek, Radek
2013-06-11
An understanding of the role of intermolecular interactions in crystal formation is essential to control the generation of diverse crystalline forms which is an important concern for pharmaceutical industry. Very recently, we reported a new approach to interpret the relationships between intermolecular hydrogen bonding, redistribution of electron density in the system, and NMR chemical shifts (Babinský et al. J. Phys. Chem. A, 2013, 117, 497). Here, we employ this approach to characterize a full set of crystal interactions in a sample of anhydrous theobromine as reflected in (13)C NMR chemical shift tensors (CSTs). The important intermolecular contacts are identified by comparing the DFT-calculated NMR CSTs for an isolated theobromine molecule and for clusters composed of several molecules as selected from the available X-ray diffraction data. Furthermore, electron deformation density (EDD) and shielding deformation density (SDD) in the proximity of the nuclei involved in the proposed interactions are calculated and visualized. In addition to the recently reported observations for hydrogen bonding, we focus here particularly on the stacking interactions. Although the principal relations between the EDD and CST for hydrogen bonding (HB) and stacking interactions are similar, the real-space consequences are rather different. Whereas the C-H···X hydrogen bonding influences predominantly and significantly the in-plane principal component of the (13)C CST perpendicular to the HB path and the C═O···H hydrogen bonding modulates both in-plane components of the carbonyl (13)C CST, the stacking modulates the out-of-plane electron density resulting in weak deshielding (2-8 ppm) of both in-plane principal components of the CST and weak shielding (∼ 5 ppm) of the out-of-plane component. The hydrogen-bonding and stacking interactions may add to or subtract from one another to produce total values observed experimentally. On the example of theobromine, we demonstrate
Tian, Donglin; Li, Tao; Zhang, Rongchun; Wu, Qiang; Chen, Tiehong; Sun, Pingchuan; Ramamoorthy, Ayyalusamy
2017-06-29
Fabricating materials with excellent mechanical performance from the natural renewable and degradable biopolymers has drawn significant attention in recent decades due to the environmental concerns and energy crisis. As two of the most promising substitutes of synthetic polymers, silk fibroin (SF), and cellulose, have been widely used in the field of textile, biomedicine, biotechnology, etc. Particularly, the cellulose/SF blend film exhibits better strength and toughness than that of regenerated cellulose film. Herein, this study is aimed to understand the molecular origin of the enhanced mechanical properties for the cellulose/SF blend film, using solid-state NMR as a main tool to investigate the conformational changes, intermolecular interactions between cellulose and SF and the water organization. It is found that the content of the β-sheet structure is increased in the cellulose/SF blend film with respect to the regenerated SF film, accompanied by the reduction of the content of random coil structures. In addition, the strong hydrogen bonding interaction between the SF and cellulose is clearly elucidated by the two-dimensional (2D) 1 H- 13 C heteronuclear correlation (HETCOR) NMR experiments, demonstrating that the SF and cellulose are miscible at the molecular level. Moreover, it is also found that the -NH groups of SF prefer to form hydrogen bonds with the hydroxyl groups bonded to carbons C2 and C3 of cellulose, while the hydroxyl groups bonded to carbon C6 and the ether oxygen are less favorable for hydrogen bonding interactions with the -NH groups of SF. Interestingly, bound water is found to be present in the air-dried cellulose/SF blend film, which is predominantly associated with the cellulose backbones as determined by 2D 1 H- 13 C wide-line-separation (WISE) experiments with spin diffusion. This clearly reveals the presence of nanoheterogeneity in the cellulose/SF blend film, although cellulose and SF are miscible at a molecular level. Without doubt
Unification of electromagnetic, strong and weak interaction
International Nuclear Information System (INIS)
Duong Van Phi; Duong Anh Duc
1993-09-01
The Unification of Electromagnetic, Strong and Weak Interactions is realized in the framework of the Quantum Field Theory, established in an 8-dimensional Unified Space. Two fundamental, spinor and vector field equations are considered. The first of the matter particles and the second is of the gauge particles. Interaction Lagrangians are formed from the external and internal currents and the external and internal vector field operators. Generators of the local gauge transformations are the combinations of the matrices of the first field equation. (author). 15 refs
Grigoryan, K. R.; Sargsyan, L. S.
2015-12-01
Features of intermolecular interactions in aqueous solutions of gallic acid (GA) are studied by means of densimetry and fluorescence spectroscopy (intrinsic fluorescence, 2D spectra, and excitation/ emission matrix fluorescence spectra, 3D) at 296.15, 301.15, and 306.15 K in the concentration range of 5.88 × 10-4-5.88 × 10-2 mol L-1. It is shown by analyzing the concentration and temperature dependences of the apparent molar volumes and fluorescence parameters of GA that the equilibrium between nonassociated and associated species in the solution and the hydration of these species undergo changes.
Super symmetry in strong and weak interactions
International Nuclear Information System (INIS)
Seshavatharam, U.V.S.; Lakshminarayana, S.
2010-01-01
For strong interaction two new fermion mass units 105.32 MeV and 11450 MeV are assumed. Existence of "Integral charge quark bosons", "Integral charge effective quark fermions", "Integral charge (effective) quark fermi-gluons" and "Integral charge quark boso-gluons" are assumed and their masses are estimated. It is noticed that, characteristic nuclear charged fermion is X s · 105.32 = 938.8 MeV and corresponding charged boson is X s (105.32/x) = 415.0 where X s = 8.914 is the inverse of the strong coupling constant and x = 2.26234 is a new number by using which "super symmetry" can be seen in "strong and weak" interactions. 11450 MeV fermion and its boson of mass = 11450/x = 5060 MeV plays a crucial role in "sub quark physics" and "weak interaction". 938.8 MeV strong fermion seems to be the proton. 415 MeV strong boson seems to be the mother of the presently believed 493,496 and 547 MeV etc, strange mesons. With 11450 MeV fermion "effective quark-fermi-gluons" and with 5060 MeV boson "quark boso-gluon masses" are estimated. "Effective quark fermi-gluons" plays a crucial role in ground state charged baryons mass generation. Light quark bosons couple with these charged baryons to form doublets and triplets. "Quark boso-gluons" plays a crucial role in ground state neutral and charged mesons mass generation. Fine and super-fine rotational levels can be given by [I or (I/2)] power(1/4) and [I or (I/2)] power(1/12) respectively. Here, I = n(n+1) and n = 1, 2, 3, … (author)
Strongly interacting matter in magnetic fields
Landsteiner, Karl; Schmitt, Andreas; Yee, Ho-Ung
2013-01-01
The physics of strongly interacting matter in an external magnetic field is presently emerging as a topic of great cross-disciplinary interest for particle, nuclear, astro- and condensed matter physicists. It is known that strong magnetic fields are created in heavy ion collisions, an insight that has made it possible to study a variety of surprising and intriguing phenomena that emerge from the interplay of quantum anomalies, the topology of non-Abelian gauge fields, and the magnetic field. In particular, the non-trivial topological configurations of the gluon field induce a non-dissipative electric current in the presence of a magnetic field. These phenomena have led to an extended formulation of relativistic hydrodynamics, called chiral magnetohydrodynamics. Hitherto unexpected applications in condensed matter physics include graphene and topological insulators. Other fields of application include astrophysics, where strong magnetic fields exist in magnetars and pulsars. Last but not least, an important ne...
Mönig, Harry; Amirjalayer, Saeed; Timmer, Alexander; Hu, Zhixin; Liu, Lacheng; Díaz Arado, Oscar; Cnudde, Marvin; Strassert, Cristian Alejandro; Ji, Wei; Rohlfing, Michael; Fuchs, Harald
2018-05-01
Atomic force microscopy is an impressive tool with which to directly resolve the bonding structure of organic compounds1-5. The methodology usually involves chemical passivation of the probe-tip termination by attaching single molecules or atoms such as CO or Xe (refs 1,6-9). However, these probe particles are only weakly connected to the metallic apex, which results in considerable dynamic deflection. This probe particle deflection leads to pronounced image distortions, systematic overestimation of bond lengths, and in some cases even spurious bond-like contrast features, thus inhibiting reliable data interpretation8-12. Recently, an alternative approach to tip passivation has been used in which slightly indenting a tip into oxidized copper substrates and subsequent contrast analysis allows for the verification of an oxygen-terminated Cu tip13-15. Here we show that, due to the covalently bound configuration of the terminal oxygen atom, this copper oxide tip (CuOx tip) has a high structural stability, allowing not only a quantitative determination of individual bond lengths and access to bond order effects, but also reliable intermolecular bond characterization. In particular, by removing the previous limitations of flexible probe particles, we are able to provide conclusive experimental evidence for an unusual intermolecular N-Au-N three-centre bond. Furthermore, we demonstrate that CuOx tips allow the characterization of the strength and configuration of individual hydrogen bonds within a molecular assembly.
A strongly interacting polaritonic quantum dot
Jia, Ningyuan; Schine, Nathan; Georgakopoulos, Alexandros; Ryou, Albert; Clark, Logan W.; Sommer, Ariel; Simon, Jonathan
2018-06-01
Polaritons are promising constituents of both synthetic quantum matter1 and quantum information processors2, whose properties emerge from their components: from light, polaritons draw fast dynamics and ease of transport; from matter, they inherit the ability to collide with one another. Cavity polaritons are particularly promising as they may be confined and subjected to synthetic magnetic fields controlled by cavity geometry3, and furthermore they benefit from increased robustness due to the cavity enhancement in light-matter coupling. Nonetheless, until now, cavity polaritons have operated only in a weakly interacting mean-field regime4,5. Here we demonstrate strong interactions between individual cavity polaritons enabled by employing highly excited Rydberg atoms as the matter component of the polaritons. We assemble a quantum dot composed of approximately 150 strongly interacting Rydberg-dressed 87Rb atoms in a cavity, and observe blockaded transport of photons through it. We further observe coherent photon tunnelling oscillations, demonstrating that the dot is zero-dimensional. This work establishes the cavity Rydberg polariton as a candidate qubit in a photonic information processor and, by employing multiple resonator modes as the spatial degrees of freedom of a photonic particle, the primary ingredient to form photonic quantum matter6.
He, Anqi; Kang, Xiaoyan; Xu, Yizhuang; Noda, Isao; Ozaki, Yukihiro; Wu, Jinguang
2017-10-05
The interaction between berberine chloride and β-cyclodextrin (β-CyD) is investigated via 2D asynchronous UV-Vis spectrum. The occurrence of cross peaks around (420nm, 420nm) in 2D asynchronous spectrum reveals that specific intermolecular interaction indeed exists between berberine chloride and β-CyD. In spite of the difficulty caused by overlapping of cross peaks, we manage to confirm that the 420nm band of berberine undergoes a red-shift, and its bandwidth decreases under the interaction with β-CyD. The red-shift of the 420nm band that can be assigned to n-π* transition indicates the environment of berberine becomes more hydrophobic. The above spectral behavior is helpful in understanding why the solubility of berberine is enhanced by β-CyD. Copyright © 2017. Published by Elsevier B.V.
New strong interactions above the electroweak scale
International Nuclear Information System (INIS)
White, A.R.
1994-01-01
Theoretical arguments for a new higher-color quark sector, based on Pomeron physics in QCD, are briefly described. The electroweak symmetry-breaking, Strong CP conservation, and electroweak scale CP violation, that is naturally produced by this sector is also outlined. A further consequence is that above the electroweak scale there will be a radical change in the strong interaction. Electroweak states, in particular multiple W's and Z's, and new, semi-stable, very massive, baryons, will be commonly produced. The possible correlation of expected phenomena with a wide range of observed Cosmic Ray effects at and above the primary spectrum knee is described. Related phenomena that might be seen in the highest energy hard scattering events at the Fermilab Tevatron, some of which could be confused with top production, are also briefly discussed
Many Body Structure of Strongly Interacting Systems
Arenhövel, Hartmuth; Drechsel, Dieter; Friedrich, Jörg; Kaiser, Karl-Heinz; Walcher, Thomas; Symposium on 20 Years of Physics at the Mainz Microtron MAMI
2006-01-01
This carefully edited proceedings volume provides an extensive review and analysis of the work carried out over the past 20 years at the Mainz Microtron (MAMI). This research centered around the application of Quantum Chromodynamics in the strictly nonperturbative regime at hadronic scales of about 1 fm. Due to the many degrees of freedom in hadrons at this scale the leitmotiv of this research is "Many body structure of strongly interacting systems". Further, an outlook on the research with the forthcoming upgrade of MAMI is given. This volume is an authoritative source of reference for everyone interested in the field of the electro-weak probing of the structure of hadrons.
Strong Interaction Studies with PANDA at FAIR
Schönning, Karin
2016-10-01
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme.
Strong Interaction Studies with PANDA at FAIR
International Nuclear Information System (INIS)
Schönning, Karin
2016-01-01
The Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany, provides unique possibilities for a new generation of nuclear-, hadron- and atomic physics experiments. The future PANDA experiment at FAIR will offer a broad physics programme with emphasis on different aspects of hadron physics. Understanding the strong interaction in the perturbative regime remains one of the greatest challenges in contemporary physics and hadrons provide several important keys. In these proceedings, PANDA will be presented along with some high-lights of the planned physics programme
Strongly interacting Higgs sector without technicolor
International Nuclear Information System (INIS)
Liu Chuan; Kuti, J.
1994-12-01
Simulation results are presented on Higgs mass calculations in the spontaneously broken phase of the Higgs sector in the minimal Standard Model with a higher derviative regulator. A heavy Higgs particle is found in the TeV mass range in the presence of a complex conjugate ghost pair at higher energies. The ghost pair evades easy experimental detection. As a finite and unitary theory in the continuum, this model serves as an explicit and simple example of a strong interacting Higgs sector without technicolor. (orig.)
Strong Interactions Physics at BaBar
Energy Technology Data Exchange (ETDEWEB)
Pioppi, M.
2005-03-14
Recent results obtained by BABAR experiment and related to strong interactions physics are presented, with particular attention to the extraction of the first four hadronic-mass moments and the first three lepton-energy moments in semileptonic decays. From a simultaneous fit to the moments, the CKM element |V{sub cb}|, the inclusive B {yields} X{sub c}lv and other heavy quark parameters are derived. The second topic is the ambiguity-free measurement of cos(2{beta}) in B {yields} J/{Psi}K* decays. With approximately 88 million of B{bar B} pairs, negative solutions for cos(2{beta}) are excluded at 89%.
Strong Interactive Massive Particles from a Strong Coupled Theory
DEFF Research Database (Denmark)
Yu. Khlopov, Maxim; Kouvaris, Christoforos
2008-01-01
(-2). These excessive techniparticles are all captured by $^4He$, creating \\emph{techni-O-helium} $tOHe$ ``atoms'', as soon as $^4He$ is formed in Big Bang Nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in Big Bang Nucleosynthesis. Due...
Finite temperature system of strongly interacting baryons
International Nuclear Information System (INIS)
Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.
1976-07-01
A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc 2 /k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10 11 0 K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light
Finite temperature system of strongly interacting baryons
Energy Technology Data Exchange (ETDEWEB)
Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.
1976-07-01
A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc/sup 2//k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10/sup 11/ /sup 0/K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light.
Asada, Naoya; Fedorov, Dmitri G.; Kitaura, Kazuo; Nakanishi, Isao; Merz, Kenneth M.
2012-01-01
We propose an approach based on the overlapping multicenter ONIOM to evaluate intermolecular interaction energies in large systems and demonstrate its accuracy on several representative systems in the complete basis set limit at the MP2 and CCSD(T) level of theory. In the application to the intermolecular interaction energy between insulin dimer and 4′-hydroxyacetanilide at the MP2/CBS level, we use the fragment molecular orbital method for the calculation of the entire complex assigned to the lowest layer in three-layer ONIOM. The developed method is shown to be efficient and accurate in the evaluation of the protein-ligand interaction energies. PMID:23050059
Combinatorial description of space and strong interactions
International Nuclear Information System (INIS)
Zenczykowski, P.
1988-01-01
A reinterpretation is given of a successful phenomenological approach to hadron self-energy effects known as the unitarized quark model. General arguments are given that the proper description of strong interactions may require abandoning the assignment of a primary role to continuous concepts such as position and momentum in favor of discrete ones such as spin or W-spin. The reinterpretation exploits an analogy between the W-spin diagrams occurring in the calculations of hadronic loop effects and the spin network idea of Penrose. A connection between the S-matrix approach to hadron masses and the purely algebraic approach characteristic of the quark model is indicated. Several hadron mass relations generated by a resulting SU(6)/sub w/-group-theoretic expression are presented and discussed. Results of an attempt to generalize the scheme to the description of hadron vertices are reported
Energy Technology Data Exchange (ETDEWEB)
Taddei, Paola, E-mail: paola.taddei@unibo.it [Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna (Italy); Tozzi, Silvia [Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, Via Belmeloro 8/2, 40126 Bologna (Italy); Zuccheri, Giampaolo [Dipartimento di Farmacia e Biotecnologie e Centro Interdipartimentale di Ricerca Industriale Scienze della Vita e Tecnologie per la Salute, Università di Bologna, Via Irnerio 48, 40126 Bologna (Italy); Centro S3, Istituto Nanoscienze, Consiglio Nazionale delle Ricerche, Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali (Italy); Martinotti, Simona; Ranzato, Elia [Dipartimento di Scienze e Innovazione Tecnologica, DiSIT, Università del Piemonte Orientale, viale Teresa Michel 11, 15121 Alessandria (Italy); Chiono, Valeria; Carmagnola, Irene [Dipartimento di Ingegneria Meccanica e Aerospaziale, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Tsukada, Masuhiro [Division of Applied Biology, Faculty of Textile Science and Technology, Shinshu University, 3-15-1, Tokida, Ueda, Nagano 386-8567 (Japan)
2017-01-01
In this study, composite nanofibrous scaffolds were obtained by electrospinning a trifluoroacetic acid solution containing B. mori silk fibroin (SF) and poly(L-lactic acid) (PLLA) in a 1:1 weight ratio. SF, PLLA and SF/PLLA nanofibres were prepared with average diameter sizes of 360 ± 90 nm, 470 ± 240 nm and 580 ± 220 nm, respectively, as assessed by SEM analysis. Vibrational and thermal analyses showed that upon blending in the SF/PLLA nanofibres, the crystallisation of PLLA was hindered by the presence of SF, which crystallized preferentially and underwent conformational changes that did not significantly change its prevailing β-sheet structure. The two components were thermodynamically compatible and the intermolecular interactions between them were revealed for the first time. Human keratinocytes were cultured on nanofibres and their viability and proliferation were determined. Preliminary in vitro tests showed that the incorporation of SF into the PLLA component enhanced cell adhesion and proliferation with respect to the unfunctionalised material. SF has been successfully used to modify the biomaterial properties and confirmed to be an efficient bioactive protein to mediate cell-biomaterial interaction. - Highlights: • Composite silk fibroin-poly(L-lactic acid) scaffolds were obtained by electrospinning. • Intermolecular interactions between SF and PLLA were revealed for the first time. • Upon blending, the crystallisation of PLLA was hindered by the presence of SF. • SF crystallized preferentially and maintained its prevailing β-sheet structure. • The incorporation of SF into PLLA enhanced human keratinocytes adhesion and proliferation.
Energy Technology Data Exchange (ETDEWEB)
Luo, Yang-Hui; Liu, Qing-Ling; Yang, Li-Jing; Ling, Yang; Wang, Wei; Sun, Bai-Wang, E-mail: chmsunbw@seu.edu.cn
2015-02-15
A new spin crossover coordination polymer (SCO-CPs) of Fe(II)-4,4′-bipyridine (4,4′-bipy) family: (Fe(4,4′-bipy){sub 2}(H{sub 2}O){sub 2})·(4,4′-bipy)· 8(H{sub 2}O)·2(ClO{sub 4}) (3), which displays half spin transitions between 100 and 300 K, has been synthesized and structurally characterized. Compound 3 featured with two-dimensional (2-D) grids connected by hydrogen bonds and π…π packing between one-dimensional (1-D) chains, the 2-D grids expand to three-dimensional (3-D) architecture supported by a “S-shaped holder” involving lattice 4-4′-bipy, water molecules and perchlorate anion. We compared 3 with the other two analogous complexes: ((Fe(4,4′-bipy) (H{sub 2}O){sub 2} (NCS){sub 2})·4,4′-bipy, 1 and (Fe(4,4′-bipy){sub 2}(NCS){sub 2})·mSolv, 2) through Hirshfeld surfaces analysis, which revealed that the low ligand field strength (NCS{sup −}) and lone-pair…H contacts contribute to the stabilization of HS (high-spin) state of the Fe(II) ion, while the high ligand field strength (4,4′-bipy) and strong intermolecular contacts (hydrogen bonds and π…π packing interactions) make for the LS (low-spin) state. - Highlights: ●A new member of Fe(||)-4,4′-bipy family has been prepared. ●It displays half spin transitions tuned by ligand field and intermolecular interactions. ●We have made a detailed comparison of this new member with two other analogous complexes.
Nichols, Pilarin; Li, Li; Kumar, Sandeep; Buck, Patrick M; Singh, Satish K; Goswami, Sumit; Balthazor, Bryan; Conley, Tami R; Sek, David; Allen, Martin J
2015-01-01
High viscosity of monoclonal antibody formulations at concentrations ≥100 mg/mL can impede their development as products suitable for subcutaneous delivery. The effects of hydrophobic and electrostatic intermolecular interactions on the solution behavior of MAB 1, which becomes unacceptably viscous at high concentrations, was studied by testing 5 single point mutants. The mutations were designed to reduce viscosity by disrupting either an aggregation prone region (APR), which also participates in 2 hydrophobic surface patches, or a negatively charged surface patch in the variable region. The disruption of an APR that lies at the interface of light and heavy chain variable domains, VH and VL, via L45K mutation destabilized MAB 1 and abolished antigen binding. However, mutation at the preceding residue (V44K), which also lies in the same APR, increased apparent solubility and reduced viscosity of MAB 1 without sacrificing antigen binding or thermal stability. Neutralizing the negatively charged surface patch (E59Y) also increased apparent solubility and reduced viscosity of MAB 1, but charge reversal at the same position (E59K/R) caused destabilization, decreased solubility and led to difficulties in sample manipulation that precluded their viscosity measurements at high concentrations. Both V44K and E59Y mutations showed similar increase in apparent solubility. However, the viscosity profile of E59Y was considerably better than that of the V44K, providing evidence that inter-molecular interactions in MAB 1 are electrostatically driven. In conclusion, neutralizing negatively charged surface patches may be more beneficial toward reducing viscosity of highly concentrated antibody solutions than charge reversal or aggregation prone motif disruption.
Transport coefficients of strongly interacting matter
International Nuclear Information System (INIS)
Heckmann, Klaus
2011-01-01
In this thesis, we investigate the dissipative transport phenomena of strongly interacting matter. The special interest is in the shear viscosity and its value divided by entropy density. The performed calculations are based on effective models for Quantum Chromodynamics, mostly focused on the 2-flavor Nambu-Jona-Lasinio model. This allows us to study the hadronic sector as well as the quark sector within one single model. We expand the models up to next-to-leading order in inverse numbers of colors. We present different possibilities of calculating linear transport coefficients and give an overview over qualitative properties as well as over recent ideas concerning ideal fluids. As present methods are not able to calculate the quark two-point function in Minkowski space-time in the self-consistent approximation scheme of the Nambu-Jona-Lasinio model, a new method for this purpose is developed. This self-energy parametrization method is applied to the expansion scheme, yielding the quark spectral function with meson back-coupling effects. The usage of this spectral function in the transport calculation is only one result of this work. We also test the application of different transport approaches in the NJL model, and find an interesting behavior of the shear viscosity at the critical end point of the phase diagram. We also use the NJL model to calculate the viscosity of a pion gas in the dilute regime. After an analysis of other models for pions and their interaction, we find that the NJL-result leads to an important modification of transport properties in comparison with the calculations which purely rely on pion properties in the vacuum. (orig.)
Strong and Electromagnetic Interactions at SPS Energies
Ribicki, Andrzej
2009-01-01
Particle production in peripheral Pb+Pb collisions has been measured at a beam energy of 158 GeV per nucleon, corresponding to psNN 17.3 GeV. The measurements provide full double differential coverage in a wide range of longitudinal and transverse momenta, including the central (“mid-rapidity”) area and extending far into the projectile fragmentation region. The resulting analysis shows the heavy ion reaction as a mixture of different processes. In particular, surprising phenomena, like the presence of large and strongly varying structures in the shape of the double differential cross section d2s /dxFd pT , are induced by the final state electromagnetic interaction between produced particles and the charged spectator system. This effect is largest at low transverse momenta, where it results in a deep valley in the xF -dependence of the produced p+/p− ratio. The basic characteristics of the electromagnetic phenomenon described above agree with the results of a theoretical analysis, performed by means of ...
Conduction properties of strongly interacting Fermions
Brantut, Jean-Philippe; Stadler, David; Krinner, Sebastian; Meineke, Jakob; Esslinger, Tilman
2013-05-01
We experimentally study the transport process of ultracold fermionic atoms through a mesoscopic, quasi two-dimensional channel connecting macroscopic reservoirs. By observing the current response to a bias applied between the reservoirs, we directly access the resistance of the channel in a manner analogous to a solid state conduction measurement. The resistance is further controlled by a gate potential reducing the atomic density in the channel, like in a field effect transistor. In this setup, we study the flow of a strongly interacting Fermi gas, and observe a striking drop of resistance with increasing density in the channel, as expected at the onset of superfluidity. We relate the transport properties to the in-situ evolution of the thermodynamic potential, providing a model independant thermodynamic scale. The resistance is compared to that of an ideal Fermi gas in the same geometry, which shows an order of magnitude larger resistance, originating from the contact resistance between the channel and the reservoirs. The extension of this study to a channel containing a tunable disorder is briefly outlined.
Toward a Strongly Interacting Scalar Higgs Particle
International Nuclear Information System (INIS)
Shalaby, Abouzeid M.; El-Houssieny, M.
2008-01-01
We calculate the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory. Rather than the corresponding Hermitian theory and due to the asymptotic freedom property of the theory, the vacuum energy does not blow up for large energy scales which is a good sign to solve the hierarchy problem when using this model to break the U(1)xSU(2) symmetry in the standard model. The theory is strongly interacting and in fact, all the dimensionful parameters in the theory like mass and energy are finite even for very high energy scales. Moreover, relative to the vacuum energy for the Hermitian φ 4 theory, the vacuum energy of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 theory is tiny, which is a good sign toward the solution of the cosmological constant problem. Remarkably, these features of the non-Hermitian and PT symmetric (-gφ 4 ) 2+1 scalar field theory make it very plausible to be employed as a Higgs mechanism in the standard model instead of the problematic Hermitian Higgs mechanism
Strong field interaction of laser radiation
International Nuclear Information System (INIS)
Pukhov, Alexander
2003-01-01
The Review covers recent progress in laser-matter interaction at intensities above 10 18 W cm -2 . At these intensities electrons swing in the laser pulse with relativistic energies. The laser electric field is already much stronger than the atomic fields, and any material is instantaneously ionized, creating plasma. The physics of relativistic laser-plasma is highly non-linear and kinetic. The best numerical tools applicable here are particle-in-cell (PIC) codes, which provide the most fundamental plasma model as an ensemble of charged particles. The three-dimensional (3D) PIC code Virtual Laser-Plasma Laboratory runs on a massively parallel computer tracking trajectories of up to 10 9 particles simultaneously. This allows one to simulate real laser-plasma experiments for the first time. When the relativistically intense laser pulses propagate through plasma, a bunch of new physical effects appears. The laser pulses are subject to relativistic self-channelling and filamentation. The gigabar ponderomotive pressure of the laser pulse drives strong currents of plasma electrons in the laser propagation direction; these currents reach the Alfven limit and generate 100 MG quasistatic magnetic fields. These magnetic fields, in turn, lead to the mutual filament attraction and super-channel formation. The electrons in the channels are accelerated up to gigaelectronvolt energies and the ions gain multi-MeV energies. We discuss different mechanisms of particle acceleration and compare numerical simulations with experimental data. One of the very important applications of the relativistically strong laser beams is the fast ignition (FI) concept for the inertial fusion energy (IFE). Petawatt-class lasers may provide enough energy to isochorically ignite a pre-compressed target consisting of thermonuclear fuel. The FI approach would ease dramatically the constraints on the implosion symmetry and improve the energy gain. However, there is a set of problems to solve before the FI
Directory of Open Access Journals (Sweden)
Saied M. Soliman
2016-12-01
Full Text Available Intermolecular interactions play a vital role in crystal structures. Therefore, we conducted a topological study, using Hirshfeld surfaces and atom in molecules (AIM analysis, to decompose and analyze, respectively, the different intermolecular interactions in six hydrazone-diacetyl platinum(II complexes. Using AIM and natural bond orbital (NBO analyses, we determined the type, nature, and strength of the interactions. All the studied complexes contain C-H⋯O interactions, and the presence of bond critical points along the intermolecular paths underlines their significance. The electron densities (ρ(r at the bond critical points (0.0031–0.0156 e/a03 fall within the typical range for H-bonding interactions. Also, the positive values of the Laplacian of the electron density (∇2ρ(r revealed the depletion of electronic charge on the interatomic path, another characteristic feature of closed-shell interactions. The ratios of the absolute potential energy density to the kinetic energy density (|V(r|/G(r and ρ(r are highest for the O2⋯H15-N3 interaction in [Pt(COMe2(2-pyCMe=NNH2] (1; hence, this interaction has the highest covalent character of all the O⋯H intermolecular interactions. Interestingly, in [Pt(COMe2(H2NN=CMe-CMe=NNH2] (3, there are significant N-H⋯Pt interactions. Using the NBO method, the second-order interaction energies, E(2, of these interactions range from 3.894 to 4.061 kJ/mol. Furthermore, the hybrid Pt orbitals involved in these interactions are comprised of dxy, dxz, and s atomic orbitals.
International Nuclear Information System (INIS)
Pandey, Puneet Kumar; Pandey, Vrijesh Kumar; Awasthi, Anjali; Nain, Anil Kumar; Awasthi, Aashees
2014-01-01
Graphical abstract: The densities and ultrasonic speeds of the binary mixtures over the entire composition range were measured at various temperatures at atmospheric pressure. The excess molar volumes, isentropic compressibilities, and molar isentropic compressions have been calculated. The variations of these parameters with composition and temperature are discussed. The IR spectra were recorded they further supported the conclusion drawn from excess parameters, which indicates the presence of intermolecular hydrogen bonding between the oxygen atom of DMAE molecules and hydrogen atom of methanol and ethanol molecules in these mixtures.. - Highlights: • The study reports density and ultrasonic velocity data of 2-(dimethylamino)ethanol + methanol/ethanol mixtures. • To elucidate the interactions in 2-(dimethylamino)ethanol + methanol/ethanol binary mixtures. • Provides information on nature and relative strength of interactions in these mixtures. • Correlates physicochemical properties with interactions in these mixtures. - Abstract: The densities, ρ and ultrasonic speeds, u of the binary mixtures of 2-(dimethylamino)ethanol (DMAE) with methanol/ethanol, including those of pure liquids, over the entire composition range were measured at 298.15, 308.15 and 318.15 K. From the experimental data, the excess molar volumes, V m E and excess isentropic compressibilities, κ s E have been calculated. The excess partial molar volumes, V ¯ m,1 E and V ¯ m,2 E and excess partial molar isentropic compressions, K ¯ s,m,1 E and K ¯ s,m,2 E over the whole composition range; and partial molar volumes, V ¯ m,1 ° and V ¯ m,2 ° , partial molar isentropic compressions, K ¯ s,m,1 ° and K ¯ s,m,2 ° , excess partial molar volumes, V ¯ m,1 °E and V ¯ m,2 °E , and excess partial molar isentropic compressions, K ¯ s,m,1 °E and K ¯ s,m,2 °E at infinite dilution have also been calculated. The variations of these parameters with composition and temperature are
International Nuclear Information System (INIS)
Krotz, R.; Neuwirth, W.; Pietsch, W.
1980-01-01
The electronic stopping cross sections for Li projectiles have been measured in various kinds of targets. They are analyzed here with respect to the different types of interactions between the constituents of the target: interactions between the atoms in a compound (chemical bonding), the ion-dipole interaction, if the target is an electrolytic solution, and the dipole-dipole interaction among polar molecules. The influence on the stopping cross section depends on the strength of these interactions; it varies from a few percent in the latter case up to 20% and more in a compound. These influences are the largest, if the velocity of the projectile is of the order of the average orbital velocity of the target atoms. (author)
da Silva, João Bosco P.; Hallwass, Fernando; da Silva, Aluizio G.; Moreira, Diogo Rodrigo; Ramos, Mozart N.; Espíndola, José Wanderlan P.; de Oliveira, Ana Daura T.; Brondani, Dalci José; Leite, Ana Cristina L.; Merz, Kenneth M.
2015-08-01
DFT calculations were used to access information about structure, energy and electronic properties of series of phenyl- and phenoxymethyl-(thio)semicarbazone derivatives with demonstrated activity against the larvae of Aedes aegypti in stage L4. The way as the thiosemicarbazone derivatives can interact with solvents like DMSO and water were analyzed from the comparison between calculated and experimental 1H NMR chemical shifts. The evidences of thiosemicarbazone derivatives making H-bond interaction to solvent have provide us insights on how they can interact with a potential A. aegypti's biological target, the Sterol Carrier Protein-2.
Conductance switching in a molecular device: The role of side groups and intermolecular interactions
DEFF Research Database (Denmark)
Taylor, Jeremy Philip; Brandbyge, Mads; Stokbro, Kurt
2003-01-01
We report first-principles studies of electronic transport in monolayers of Tour wires functionalized with different side groups. An analysis of the scattering states and transmission eigenchannels suggests that the functionalization does not strongly affect the resonances responsible for current...
Sk, Rejaul; Dhara, Barun; Miller, Joel; Deshpande, Aparna
Submolecular resolution scanning tunneling microscopy (STM) of copper octacyanophthalocyanine, CuPc(CN)8, at 77 K demonstrates that these achiral molecules form a two dimensional (2D) tetramer-based self-assembly upon evaporation onto an atomically flat Au(111) substrate. They assemble in two different structurally chiral configurations upon adsorption on Au(111). Scanning tunneling spectroscopy (STS),acquired at 77 K, unveils the HOMO and LUMO energy levels of this self-assembly. Voltage dependent STM images show that each molecule in both the structurally chiral configurations individually becomes chiral by breaking the mirror symmetry due to the enhanced intermolecular dipolar coupling interaction at the LUMO energy while the individual molecules remain achiral at the HOMO energy and within the HOMO-LUMO gap. At the LUMO energy, the handedness of the each chiral molecule is decided by the direction of the dipolar coupling interaction in the tetramer unit cell. This preference for LUMO energy indicates that this chirality is purely electronic in nature and it manifests on top of the organizational chirality that is present in the self-assembly independent of the orbital energy. Supported by IISER Pune and DAE-BRNS, India (Project No. 2011/20/37C/17/BRNS).
Ashfaq, Muhammad; Arshad, Muhammad Nadeem; Danish, Muhammad; Asiri, Abdullah M.; Khatoon, Sadia; Mustafa, Ghulam; Zolotarev, Pavel N.; Butt, Rabia Ayub; Şahin, Onur
2016-01-01
Tranexamic acid (4-aminomethyl-cyclohexanecarboxylic acid) was reacted with sulfonyl chlorides to produce structurally related four sulfonamide derivatives using simple and environmental friendly method to check out their three-dimensional behavior and van der Walls interactions. The molecules were crystallized in different possibilities, as it is/after alkylation at its O and N atoms/along with a co-molecule. All molecules were crystallized in monoclinic crystal system with space group P21/n, P21/c and P21/a. X-ray studies reveal that the molecules stabilized themselves by different kinds of hydrogen bonding interactions. The molecules are getting connected through O-H⋯O hydrogen bonds to form inversion dimers which are further connected through N-H⋯O interactions. The molecules in which N and O atoms were alkylated showed non-classical interaction and generated centro-symmetric R22(24) ring motif. The co-crystallized host and guest molecules are connected to each other via O-H⋯O interactions to generate different ring motifs. By means of the ToposPro software an analysis of the topologies of underlying nets that correspond to molecular packings and hydrogen-bonded networks in structures under consideration was carried out.
Accurate Intermolecular Interaction Energies from a Combination of MP2 and TDDFT Response Theory
Czech Academy of Sciences Publication Activity Database
Pitoňák, Michal; Hesselmann, A.
2010-01-01
Roč. 6, č. 1 (2010), s. 168-178 ISSN 1549-9618 R&D Projects: GA MŠk LC512 Grant - others:VEGA(SK) 1/0428/09 Institutional research plan: CEZ:AV0Z40550506 Keywords : dispersion energy * TDDFT * noncovalent interactions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.138, year: 2010
International Nuclear Information System (INIS)
Guan, Jiwen; Hu, Yongjun; Xie, Min; Bernstein, Elliot R.
2012-01-01
Highlights: ► The carbonyl overtone of acetone clusters is observed by IR-VUV spectroscopy. ► Acetone molecules in the dimer are stacked with an antiparallel way. ► The structure of the acetone trimer and the tetramer are the cyclic structures. ► The carbonyl groups would interact with the methyl groups in acetone clusters. ► These weak interactions are further confirmed by H/D substitution experiment. -- Abstract: Size-selected IR–VUV spectroscopy is employed to detect vibrational characteristics in the region 2850 ∼ 3550 cm −1 of neutral acetone and its clusters (CH 3 COCH 3 ) n (n = 1–4). Features around 3440 cm −1 in the spectra of acetone monomer and its clusters are assigned to the carbonyl stretch (CO) overtone. These features red-shift from 3455 to 3433 cm −1 as the size of the clusters increases from the monomer to the tetramer. Based on calculations, the experimental IR spectra in the C=O overtone region suggest that the dominant structures for the acetone trimer and tetramer should be cyclic in the supersonic expansion sample. This study also suggests that the carbonyl groups interact with the methyl groups in the acetone clusters. These weak interactions are further confirmed by the use of deuterium substitution.
Raut, Ashlesha S; Kalonia, Devendra S
2015-04-01
Opalescence indicates physical instability of a formulation because of the presence of aggregates or liquid-liquid phase separation in solution and has been reported for monoclonal antibody (mAb) formulations. Increased solution opalescence can be attributed to attractive protein-protein interactions (PPIs). Techniques including light scattering, AUC, or membrane osmometry are routinely employed to measure PPIs in dilute solutions, whereas opalescence is seen at relatively higher concentrations, where both long- and short-range forces contribute to overall PPIs. The mAb molecule studied here shows a unique property of high opalescence because of liquid-liquid phase separation. In this study, opalescence measurements are correlated to PPIs measured in diluted and concentrated solutions using light scattering (kD ) and high-frequency rheology (G'), respectively. Charges on the molecules were calculated using zeta potential measurements. Results indicate that high opalescence and phase separation are a result of the attractive interactions in solution; however, the presence of attractive interactions do not always imply phase separation. Temperature dependence of opalescence suggests that thermodynamic contribution to opalescence is significant and Tcloud can be utilized as a potential tool to assess attractive interactions in solution. © 2014 Wiley Periodicals, Inc. and the American Pharmacists Association.
De Sitter vacua of strongly interacting QFT
Energy Technology Data Exchange (ETDEWEB)
Buchel, Alex [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Department of Physics and Astronomy, University of Western Ontario,London, Ontario N6A 5B7 (Canada); Perimeter Institute for Theoretical Physics,Waterloo, Ontario N2J 2W9 (Canada); Karapetyan, Aleksandr [Department of Applied Mathematics, University of Western Ontario,London, Ontario N6A 5B7 (Canada)
2017-03-22
We use holographic correspondence to argue that Euclidean (Bunch-Davies) vacuum is a late-time attractor of the dynamical evolution of quantum gauge theories at strong coupling. The Bunch-Davies vacuum is not an adiabatic state, if the gauge theory is non-conformal — the comoving entropy production rate is nonzero. Using the N=2{sup ∗} gauge theory holography, we explore prospects of explaining current accelerated expansion of the Universe as due to the vacuum energy of a strongly coupled QFT.
International Nuclear Information System (INIS)
Zafarani-Moattar, Mohammed Taghi; Dehghanian, Saeedeh
2014-01-01
Highlights: • Density and viscosity values of PEG400 + methoxybenzene or + ethoxybenzene were measured. • The excess molar volume and thermodynamic functions of activation were calculated. • The results were interpreted in light of polymer–solvent interactions. • The changes in activation function indicate the viscous flow process. • The thermodynamic functions were correlated with the suitable equations. -- Abstract: The density and viscosity values of the binary mixtures of {poly (ethylene glycol) (PEG400) + methoxybenzene, or + ethoxybenzene} have been measured at T = (298.15, 308.15, and 318.15) K. From these experimental values, the excess molar volume, apparent specific volume, partial specific volume of solute, partial specific volume of solvent and excess Gibbs free energy of activation have been computed over the entire range of composition at three temperatures. From the experimental data, the thermodynamic functions of activation have been estimated for each binary mixture. The obtained results have been interpreted in light of polymer–solvent interactions and packing effects. The signs of excess molar volume and deviations of excess Gibbs free energy of activation have been used to obtain some information in regard to existence of specific interactions between PEG400 and solvents molecules. The changes in entropy and enthalpy of activation from the initial state to the transition state were also calculated in order to see which one of these functions controls viscous flow process in the studied polymer solutions. The excess molar volume and excess Gibbs free energy of activation values have been adequately fitted to the Redlich–Kister polynomial. Apparent specific volume values were correlated with the suitable equation. The different models proposed for correlating the viscosity of polymer solutions or liquid mixtures (segment-based-Eyring–NRTL, segment-based-Eyring–Wilson, Grunbreg–Nissan, Frenkel, Hind et al., Katti
Endoh, Tamaki; Sugimoto, Naoki
2015-08-04
Conformational transitions of biomolecules in response to specific stimuli control many biological processes. In natural functional RNA switches, often called riboswitches, a particular RNA structure that has a suppressive or facilitative effect on gene expression transitions to an alternative structure with the opposite effect upon binding of a specific metabolite to the aptamer region. Stability of RNA secondary structure (-ΔG°) can be predicted based on thermodynamic parameters and is easily tuned by changes in nucleobases. We envisioned that tuning of a functional RNA switch that causes an allosteric interaction between an RNA and a peptide would be possible based on a predicted switching energy (ΔΔG°) that corresponds to the energy difference between the RNA secondary structure before (-ΔG°before) and after (-ΔG°after) the RNA conformational transition. We first selected functional RNA switches responsive to neomycin with predicted ΔΔG° values ranging from 5.6 to 12.2 kcal mol(-1). We then demonstrated a simple strategy to rationally convert the functional RNA switch to switches responsive to natural metabolites thiamine pyrophosphate, S-adenosyl methionine, and adenine based on the predicted ΔΔG° values. The ΔΔG° values of the designed RNA switches proportionally correlated with interaction energy (ΔG°interaction) between the RNA and peptide, and we were able to tune the sensitivity of the RNA switches for the trigger molecule. The strategy demonstrated here will be generally applicable for construction of functional RNA switches and biosensors in which mechanisms are based on conformational transition of nucleic acids.
DEFF Research Database (Denmark)
Aloshyna, Mariya; Medina, Begona Milian; Poulsen, Lars
2008-01-01
-guest interactions are elucidated by UV/Vis and Raman spectroscopy. The impact of the local environment of the chromophore on the optical and photophysical properties is discussed in light of quantum-chemical calculations. In stark contrast to thin films where preferential side-by-side orientation leads to quenching...... of photoluminescence (PL) via non-emissive traps, the ICs are found to be attractive materials for opto-electronic applications: they offer high chromophore concentrations, but at the same time behave as quasi-isolated entities of tightly packed, well-oriented objects with high PL quantum yields and the possibility...
Perturbation theory of intermolecular interactions: What is the problem, are there solutions?
International Nuclear Information System (INIS)
Adams, W.H.
1990-01-01
We review the nature of the problem in the framework of Rayleigh-Schroedinger perturbation theory (the polarization approximation) considering explicitly two examples: the interaction of two hydrogen atoms and the interaction of Li with H. We show, in agreement with the work of Claverie and of Morgan and Simon, that the LiH problem is dramatically different from the H 2 problem. In particular, the physical states of LiH are higher in energy than an infinite number of discrete, unphysical states and they are buried in a continuum of unbound, unphysical states, which starts well below the lowest physical state. Clavrie has shown that the perturbation expansion, under these circumstances, is likely to converge to an unphysical state of lower energy than the physical ground state, if it converges at all. We review, also, the application of two classes of exchange perturbation theory to LiH and larger systems. We show that the spectra of three Eisenschitz-London (EL) class, exchange perturbation theories have no continuum of unphysical states overlaying the physical states and no discrete, unphysical states below the lowest physical state. In contrast, the spectra of two Hirschfelder-Silbey class theories differ hardly at all from that found with the polarization approximation. Not one of the EL class of perturbation theories, however, eliminates all of the discrete unphysical states
Liu, Yuan; Zhao, Jijun; Li, Fengyu; Chen, Zhongfang
2013-01-15
Accurate description of hydrogen-bonding energies between water molecules and van der Waals interactions between guest molecules and host water cages is crucial for study of methane hydrates (MHs). Using high-level ab initio MP2 and CCSD(T) results as the reference, we carefully assessed the performance of a variety of exchange-correlation functionals and various basis sets in describing the noncovalent interactions in MH. The functionals under investigation include the conventional GGA, meta-GGA, and hybrid functionals (PBE, PW91, TPSS, TPSSh, B3LYP, and X3LYP), long-range corrected functionals (ωB97X, ωB97, LC-ωPBE, CAM-B3LYP, and LC-TPSS), the newly developed Minnesota class functionals (M06-L, M06-HF, M06, and M06-2X), and the dispersion-corrected density functional theory (DFT) (DFT-D) methods (B97-D, ωB97X-D, PBE-TS, PBE-Grimme, and PW91-OBS). We found that the conventional functionals are not suitable for MH, notably, the widely used B3LYP functional even predicts repulsive interaction between CH(4) and (H(2)O)(6) cluster. M06-2X is the best among the M06-Class functionals. The ωB97X-D outperforms the other DFT-D methods and is recommended for accurate first-principles calculations of MH. B97-D is also acceptable as a compromise of computational cost and precision. Considering both accuracy and efficiency, B97-D, ωB97X-D, and M06-2X functional with 6-311++G(2d,2p) basis set without basis set superposition error (BSSE) correction are recommended. Though a fairly large basis set (e.g., aug-cc-pVTZ) and BSSE correction are necessary for a reliable MP2 calculation, DFT methods are less sensitive to the basis set and BSSE correction if the basis set is sufficient (e.g., 6-311++G(2d,2p)). These assessments provide useful guidance for choosing appropriate methodology of first-principles simulation of MH and related systems. © 2012 Wiley Periodicals, Inc. Copyright © 2012 Wiley Periodicals, Inc.
Electromagnetic probes of strongly interacting matter
Indian Academy of Sciences (India)
2015-05-07
May 7, 2015 ... Collisions between two nuclei at relativistic energies will create charged particles – either in .... The thermal cutting rules give a systematic procedure to express ...... mesons due to its interaction with the thermal partons [80] and employment of running .... [16] J Deng, Q Wang, N Xu and P Zhuang, Phys. Lett.
Relativistic rapprochement of electromagnetic and strong interactions
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1995-01-01
On the basis of the Lienard-Wiechert potential and the relativistic Yukawa potential it is shown that the corresponding interactions with velocity growth increase differently (the electromagnetic one increases faster). According to preliminary estimations they are equivalent, at distances of the 'action radius' of nuclear forces, at γ≅ 960, where γ is the Lorentz factor. 2 refs
Fabrication and Intermolecular Interactions of Silk Fibroin/Hydroxybutyl Chitosan Blended Nanofibers
Directory of Open Access Journals (Sweden)
Xiu-Mei Mo
2011-03-01
Full Text Available The native extracellular matrix (ECM is composed of a cross-linked porous network of multifibril collagens and glycosaminoglycans. Nanofibrous scaffolds of silk fibroin (SF and hydroxybutyl chitosan (HBC blends were fabricated using 1,1,1,3,3,3-hexaﬂuoro-2-propanol (HFIP and trifluoroacetic acid (TFA as solvents to biomimic the native ECM via electrospinning. Scanning electronic microscope (SEM showed that relatively uniform nanofibers could be obtained when 12% SF was blended with 6% HBC at the weight ratio of 50:50. Meanwhile, the average nanoﬁbrous diameter increased when the content of HBC in SF/HBC blends was raised from 20% to 100%. Fourier transform infrared spectra (FTIR and 13C nuclear magnetic resonance (NMR showed SF and HBC molecules existed in hydrogen bonding interactions but HBC did not induce conformation of SF transforming from random coil form to β-sheet structure. X-ray diffraction (XRD confirmed the different structure of SF/HBC blended nanofibers from both SF and HBC. Thermogravimetry-Differential thermogravimetry (TG-DTG results demonstrated that the thermal stability of SF/HBC blend nanofibrous scaffolds was improved. The results indicated that the rearrangement of HBC and SF molecular chain formed a new structure due to stronger hydrogen bonding between SF and HBC. These electrospun SF/HBC blended nanofibers may provide an ideal tissue engineering scaffold and wound dressing.
Shi, Jie-Hua; Lou, Yan-Yue; Zhou, Kai-Li; Pan, Dong-Qi
2018-03-01
Fenhexamid, as a hydroxyanilide, is widely applied to control Botrytis cinerea for protecting crops and fruits. But it could adversely affect human and animals health due to accumulation of residues in food production. Here, the affinity characteristics of fenhexamid on bovine serum albumin (BSA) was studied via a series of spectroscopic methods such as steady-state fluorescence spectroscopy, ultraviolet spectroscopy (UV), synchronous fluorescence spectroscopy (SFS), 3D fluorescence spectroscopy, and fourier transform infrared spectroscopy (FT-IR). The experimental results illustrated that the fluorescence quenching mechanism of BSA induced by fenhexamid was a static quenching. The binding constant (K b ) of fenhexamid with BSA was 2.399 × 10 4 M -1 at 298 K and the combination ratio was about 1:1. The competitive experiment demonstrated that fenhexamid was binding on the BSA at site II (subdomain IIIA), which was confirmed by the molecular docking studies. The negative values of thermodynamic parameter (ΔH 0 , ΔS 0 and ΔG 0 ) revealed that the reaction of fenhexamid with BSA could proceed spontaneously, the van der Waals force and hydrogen bonding interaction conducted the main effect, and the binding process was enthalpy-driven. What's more, the 8-Anilino-1-naphthalenesulfonate (ANS) and sucrose binding studies were also performed and further verified the binding force between BSA and fenhexamid. Copyright © 2018 Elsevier B.V. All rights reserved.
Spectroscopic Characterization of Intermolecular Interaction of Amyloid β Promoted on GM1 Micelles
Directory of Open Access Journals (Sweden)
Maho Yagi-Utsumi
2011-01-01
Full Text Available Clusters of GM1 gangliosides act as platforms for conformational transition of monomeric, unstructured amyloid β (Aβ to its toxic β-structured aggregates. We have previously shown that Aβ(1–40 accommodated on the hydrophobic/hydrophilic interface of lyso-GM1 or GM1 micelles assumes α-helical structures under ganglioside-excess conditions. For better understanding of the mechanisms underlying the α-to-β conformational transition of Aβ on GM1 clusters, we performed spectroscopic characterization of Aβ(1–40 titrated with GM1. It was revealed that the thioflavin T- (ThT- reactive β-structure is more populated in Aβ(1–40 under conditions where the Aβ(1–40 density on GM1 micelles is high. Under this circumstance, the C-terminal hydrophobic anchor Val39-Val40 shows two distinct conformational states that are reactive with ThT, while such Aβ species were not generated by smaller lyso-GM1 micelles. These findings suggest that GM1 clusters promote specific Aβ-Aβ interactions through their C-termini coupled with formation of the ThT-reactive β-structure depending on sizes and curvatures of the clusters.
Relativistic rapprochement of weak and strong interactions
International Nuclear Information System (INIS)
Strel'tsov, V.N.
1995-01-01
On the basis of the relativistic Yukawa potentials for the nuclear (quark) field and the field of intermediate vector W-, Z-bosons, it is shown that the interactions described by them increase differently with growing velocity (the weak one increases more rapidly). According to the estimates, they are compared (at distances of the 'action radius' of nuclear forces) at an energy of about 10 12 GeV (10 6 GeV for the pion field) what is smaller than the corresponding value in the model of 'grand unification'. 3 refs., 2 tabs
Strong Interactions, (De)coherence and Quarkonia
Bellucci, Stefano; Tiwari, Bhupendra Nath
2011-01-01
Quarkonia are the central objects to explore the non-perturbative nature of non-abelian gauge theories. We describe the confinement-deconfinement phases for heavy quarkonia in a hot QCD medium and thereby the statistical nature of the inter-quark forces. In the sense of one-loop quantum effects, we propose that the "quantum" nature of quark matters follows directly from the thermodynamic consideration of Richardson potential. Thereby we gain an understanding of the formation of hot and dense states of quark gluon plasma matter in heavy ion collisions and the early universe. In the case of the non-abelian theory, the consideration of the Sudhakov form factor turns out to be an efficient tool for soft gluons. In the limit of the Block-Nordsieck resummation, the strong coupling obtained from the Sudhakov form factor yields the statistical nature of hadronic bound states, e.g. kaons and Ds particles.
Strong and electromagnetic interactions in hadron systems
International Nuclear Information System (INIS)
Aissat, N.; Amghar, A.; Cano, F.; Gonzalez, F.; Noguera, S.; Carbonell, J.; Desplanques, B.; Silvestre-Brac, B.; Karmanov, V.; Mathiot, J.F.
1997-01-01
The pionic strong decay amplitudes of baryon resonances are studied in a constituent quark model. Particular attention is given to the operator describing the transition. The nucleon form factors are calculated in a non-relativistic approach, with emphasis on the highest momentum transfers. The aim is to determine the ingredients that are essential in getting correct results and are likely to be required for a more realistic estimate in a fully relativistic approach. The deuteron form factors have been calculated in the light-front approach using wave functions determined in a perturbative way. The derivation of the neutron charge form factor from the deuteron structure function, A(q 2 ), is reanalyzed including further mesonic exchange contributions. (authors)
"Strong interaction" for particle physics laboratories
2003-01-01
A new Web site pooling the communications resources of particle physics centres all over the world has just been launched. The official launching of the new particle physics website Interactions.org during the Lepton-Proton 2003 Conference at the American laboratory Fermilab was accompanied by music and a flurry of balloons. On the initiative of Fermilab, the site was created by a collaboration of communication teams from over fifteen of the world's particle physics laboratories, including KEK, SLAC, INFN, JINR and, of course, CERN, who pooled their efforts to develop the new tool. The spectacular launching of the new particle physics website Interactions.org at Fermilab on 12 August 2003. A real gateway to particle physics, the site not only contains all the latest news from the laboratories but also offers images, graphics and a video/animation link. In addition, it provides information about scientific policies, links to the universities, a very useful detailed glossary of particle physics and astrophysic...
Supersymmetry and weak, electromagnetic and strong interactions
International Nuclear Information System (INIS)
Fayet, P.
1977-01-01
A supersymmetric theory of particle interactions is discussed. It is based on the earlier model which involves gauge (or vector) superfields, and matter (or chiral) superfields; each of them describes a vector and a Majorana spinor in the first case, or a two-component Dirac spinor and a complex scalar in the second case. The new theory suggests the possible existence of spin - 1/2 gluons and heavy spin-0 quarks, besides spin - 1 gluons and spin - 1/2 quarks. To prevent scalar particles to be exchanged in processes such as μ or β decays a new class of leptons with its own quantum number is introduced; it includes charged leptons and a ''photonic neutrino''
Gu, Jianmin; Yin, Baipeng; Fu, Shaoyan; Jin, Cuihong; Liu, Xin; Bian, Zhenpan; Li, Jianjun; Wang, Lu; Li, Xiaoyu
2018-03-01
Due to the intense influence of the shape and size of the photon building blocks on the limitation and guidance of optical waves, an important strategy is the fabrication of different structures. Herein, organic semiconductor tris-(8-hydroxyquinoline)aluminium (Alq3) nanostructures with controllable morphology, ranging from one-dimensional nanowires to two-dimensional plates, have been prepared through altering intermolecular interactions with employing the anti-solvent diffusion cooperate with solvent-volatilization induced self-assembly method. The morphologies of the formed nanostructures, which are closely related to the stacking modes of the molecules, can be exactly controlled by altering the polarity of anti-solvents that can influence various intermolecular interactions. The synthesis strategy reported here can potentially be extended to other functional organic nanomaterials.
Signatures for strongly interacting W's and Z's
International Nuclear Information System (INIS)
Gaillard, M.K.
1985-09-01
The observed structure of the electroweak interactions is understood in terms of a spontaneously broken gauge theory. Although we have as yet no experimental indication as to the nature of the phenomenon responsible for symmetry breaking, general theoretical arguments set an upper limit of 1 or 2 TeV on the energy scale at which some manifestation of this phenomenon must occur. This scale defines a target for the effective hard collision energy that should be achieved in the next accelerator facility; the work reported here was aimed at sharpening this requirement by studying the minimal manifestations of electroweak symmetry breaking that can be expected to occur in the TeV energy region if a Higgs particle with m/sub H/ < 1 TeV is not found. While we used the minimal Higgs model as a guide, the results obtained are of far more general validity. Our analysis relied on three tools, briefly discussed. These are: the equivalence at high energies of longitudinally polarized W's and Z's to their scalar counterparts, the Goldstone bosons; the symmetries of the scalar sector; and the vector boson fusion process. 8 refs
QCD : the theory of strong interactions Conference MT17
2001-01-01
The theory of strong interactions,Quantum Chromodynamics (QCD), predicts that the strong interaction is transmitted by the exchange of particles called gluons. Unlike the messengers of electromagnetism photons, which are electrically neutral - gluons carry a strong charge associated with the interaction they mediate. QCD predicts that the strength of the interaction between quarks and gluons becomes weaker at higher energies. LEP has measured the evolution of the strong coupling constant up to energies of 200 GeV and has confirmed this prediction.
DEFF Research Database (Denmark)
Jensen, Anders A.; Hansen, Jakob L; Sheikh, Søren P
2002-01-01
-induced intermolecular movements in the CaR homodimer using the new bioluminescence resonance energy transfer technique, BRET2, which is based on the transference of energy from Renilla luciferase (Rluc) to the green fluorescent protein mutant GFP2. We tagged CaR with Rluc and GFP2 at different intracellular locations...
Dynamics of Strong Interactions and the S-Matrix
Energy Technology Data Exchange (ETDEWEB)
Omnes, R. [Laboratoire de Physique Theorique et Hautes Energies, Universite de Paris, Orsay (France)
1969-08-15
The physical principles underlying the S-matrix theory of strong interactions are reviewed. In particular, the problem of whether these principles are sufficient to completely determine the S-matrix, i.e. to yield a dynamical theory of strong interactions, is discussed. (author)
Strong enhancement of transport by interaction on contact links
DEFF Research Database (Denmark)
Bohr, Dan; Schmitteckert, P.
2007-01-01
Strong repulsive interactions within a one-dimensional Fermi system in a two-probe configuration normally lead to a reduced off-resonance conductance. We show that if the repulsive interaction extends to the contact regions, a strong increase of the conductance may occur, even for systems where o...
QCD : the theory of strong interactions Exhibition LEPFest 2000
2000-01-01
The theory of strong interactions,Quantum Chromodynamics (QCD),predicts that the strong interac- tion is transmitted by the exchange of particles called glu- ons.Unlike the messengers of electromagnetism -pho- tons,which are electrically neutral -gluons carry a strong charge associated with the interaction they mediate. QCD predicts that the strength of the interaction between quarks and gluons becomes weaker at higher energies.LEP has measured the evolution of the strong coupling constant up to energies of 200 GeV and has confirmed this prediction.
Numerical Calculation of the Phase Space Density for the Strong-Strong Beam-Beam Interaction
International Nuclear Information System (INIS)
Sobol, A.; Ellison, J.A.
2003-01-01
We developed a parallel code to calculate the evolution of the 4D phase space density of two colliding beams, which are coupled via the collective strong-strong beam-beam interaction, in the absence of diffusion and damping, using the Perron-Frobenius (PF) operator technique
Prospects for strong interaction physics at ISABELLE. [Seven papers
Energy Technology Data Exchange (ETDEWEB)
Sidhu, D P; Trueman, T L
1977-01-01
Seven papers are presented resulting from a conference intended to stimulate thinking about how ISABELLE could be used for studying strong interactions. A separate abstract was prepared for each paper for inclusion in DOE Energy Research Abstracts (ERA). (PMA)
A theory of strong interactions ''from'' general relativity
International Nuclear Information System (INIS)
Caldirola, P.; Recami, E.
1979-01-01
In this paper a previous letter (where, among other things, a classical ''quark confinement'' was derived from general relativity plus dilatation-covariance), is completed by showing that the theory is compatible also with quarks ''asymptotic freedom''. Then -within a bi-scale theory of gravitational and strong interactions- a classical field theory is proposed for the (strong) interactions between hadrons. Various consequences are briefly analysed
Measurement of strong interaction effects in antiprotonic helium atoms
International Nuclear Information System (INIS)
Davies, J.D.; Gorringe, T.P.; Lowe, J.; Nelson, J.M.; Playfer, S.M.; Pyle, G.J.; Squier, G.T.A.
1984-01-01
The strong interaction shift and width for the 2 p level and the width for the 3d level have been measured for antiprotonic helium atoms. The results are compared with optical model calculations. The possible existence of strongly bound antiproton states in nuclei is discussed. (orig.)
Directory of Open Access Journals (Sweden)
Matthew J. Montgomery
2015-07-01
Full Text Available The two title compounds are isomers of C6H3ClN2 containing a pyridine ring, a nitrile group, and a chloro substituent. The molecules of each compound pack together in the solid state with offset face-to-face π-stacking, and intermolecular C—H...Nnitrile and C—H...Npyridine interactions. 4-Chloropyridine-2-carbonitrile, (I, exhibits pairwise centrosymmetric head-to-head C—H...Nnitrile and C—H...Npyridine interactions, forming one-dimensional chains, which are π-stacked in an offset face-to-face fashion. The intermolecular packing of the isomeric 6-chloropyridine-2-carbonitrile, (II, which differs only in the position of the chloro substituent on the pyridine ring, exhibits head-to-tail C—H...Nnitrile and C—H...Npyridine interactions, forming two-dimensional sheets which are π-stacked in an offset face-to-face fashion. In contrast to (I, the offset face-to-face π-stacking in (II is formed between molecules with alternating orientations of the chloro and nitrile substituents.
Interaction between Electron Holes in a Strongly Magnetized Plasma
DEFF Research Database (Denmark)
Lynov, Jens-Peter; Michelsen, Poul; Pécseli, Hans
1980-01-01
The interaction between electron holes in a strongly magnetized, plasma-filled waveguide is investigated by means of computer simulation. Two holes may or may not coalesce, depending on their amplitudes and velocities. The interaction between holes and Trivelpiece-Gould solitons is demonstrated...
Quark imprisonment as the origin of strong interactions
Amati, Daniele
1974-01-01
A formal scheme is suggested in which the only dynamical ingredients are weak and electro-magnetic interactions with quarks and leptons treated on the same footing. Strong interactions are generated by the requirement that quarks do not appear physically. (7 refs).
Substructure and strong interactions at the TeV scale
International Nuclear Information System (INIS)
Peskin, M.E.
1985-12-01
A review is given of the current status of the three main theoretical ideas relevant to strong-interaction 1 TeV physics. These are composite vector bosons, Higgs bosons (''Technicolor''), and matter fermions. All involve the assumption that some object which is assumed to be fundamental in the standard model actually has dynamical internal structure. Complex, mechanistic models of the new physics are discussed. A brief digression is then made on how the weak interaction allows probing for this new structure. Direct manifestations of new 1 TeV strong interactions are discussed. 125 refs., 18 figs
Semicalssical quantization of interacting anyons in a strong magnetic field
International Nuclear Information System (INIS)
Levit, S.; Sivan, N.
1992-01-01
We represent a semiclassical theory of charged interacting anyons in strong magnetic fields. We apply this theory to a number of few anyons systems including two interacting anyons in the presence of an impurity and three interacting anyons. We discuss the dependence of their energy levels on the statistical parameter and find regions in which this dependence follows very different patterns. The semiclassical arguments allow to correlate these patterns with the change in the character of the classical motion of the system. (author)
International Nuclear Information System (INIS)
Power, E.A.; Thirunamachandran, T.
1993-01-01
Spatial correlations between electromagnetic fields arising from neutral sources with electric-dipole transition moments are calculated using nonrelativistic quantum electrodynamics in the multipolar formalism. Expressions for electric-electric, magnetic-magnetic, and electric-magnetic correlation functions at two points r and r' are given for a source molecule in either a ground or an excited state. In contrast to the electric-electric and magnetic-magnetic cases there are no electric-magnetic correlations for a ground-state molecule. For an excited molecule the downward transitions contribute additional terms which have modulating factors depending on (r-r')/λ. From these correlation functions electric and magnetic energy densities are found by setting r=r'. These energy densities are then used in a response formalism to calculate intermolecular energy shifts. In the case of two ground-state molecules this leads to the Casimir-Polder potential. However, for a pair of molecules, one or both excited, there are additional terms arising from downward transitions. An important feature of these energies is that they exhibit an R -2 dependence for large intermolecular separations R. This dependence is interpreted in terms of the Poynting vector, which itself can be obtained by setting r=r' in the electric-magnetic correlation function
Mixtures of Strongly Interacting Bosons in Optical Lattices
International Nuclear Information System (INIS)
Buonsante, P.; Penna, V.; Giampaolo, S. M.; Illuminati, F.; Vezzani, A.
2008-01-01
We investigate the properties of strongly interacting heteronuclear boson-boson mixtures loaded in realistic optical lattices, with particular emphasis on the physics of interfaces. In particular, we numerically reproduce the recent experimental observation that the addition of a small fraction of 41 K induces a significant loss of coherence in 87 Rb, providing a simple explanation. We then investigate the robustness against the inhomogeneity typical of realistic experimental realizations of the glassy quantum emulsions recently predicted to occur in strongly interacting boson-boson mixtures on ideal homogeneous lattices
New results on strong-interaction effects in antiprotonic hydrogen
Gotta, D; Augsburger, M A; Borchert, G L; Castelli, C M; Chatellard, D; El-Khoury, P; Egger, J P; Gorke, H; Hauser, P R; Indelicato, P J; Kirch, K; Lenz, S; Nelms, N; Rashid, K; Schult, O W B; Siems, T; Simons, L M
1999-01-01
Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the low-energy antiproton ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using charge-coupled devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction. (33 refs).
New results on strong-interaction effects in antiprotonic hydrogen
International Nuclear Information System (INIS)
Anagnostopoulos, D. F.; Augsburger, M.; Borchert, G.; Castelli, C.; Chatellard, D.; El-Khoury, P.; Egger, J.-P.; Gorke, H.; Gotta, D.; Hauser, P.; Indelicato, P.; Kirch, K.; Lenz, S.; Nelms, N.; Rashid, K.; Schult, O. W. B.; Siems, Th.; Simons, L. M.
1999-01-01
Lyman and Balmer transitions of antiprotonic hydrogen and deuterium have been measured at the Low-Energy Antiproton Ring LEAR at CERN in order to determine the strong interaction effects. The X-rays were detected using Charge-Coupled Devices (CCDs) and a reflection type crystal spectrometer. The results of the measurements support the meson-exchange models describing the medium and long range part of the nucleon-antinucleon interaction
H. David Politzer, Asymptotic Freedom, and Strong Interaction
dropdown arrow Site Map A-Z Index Menu Synopsis H. David Politzer, Asymptotic Freedom, and Strong Interaction Resources with Additional Information H. David Politzer Photo Credit: California Institute of Technology H. David Politzer has won the 2004 Nobel Prize in Physics 'for the discovery of asymptotic freedom
Emergence of junction dynamics in a strongly interacting Bose mixture
DEFF Research Database (Denmark)
Barfknecht, Rafael Emilio; Foerster, Angela; Zinner, Nikolaj Thomas
We study the dynamics of a one-dimensional system composed of a bosonic background and one impurity in single- and double-well trapping geometries. In the limit of strong interactions, this system can be modeled by a spin chain where the exchange coefficients are determined by the geometry of the...
Interplay of Anderson localization and strong interaction in disordered systems
International Nuclear Information System (INIS)
Henseler, Peter
2010-01-01
We study the interplay of disorder localization and strong local interactions within the Anderson-Hubbard model. Taking into account local Mott-Hubbard physics and static screening of the disorder potential, the system is mapped onto an effective single-particle Anderson model, which is studied within the self-consistent theory of electron localization. For fermions, we find rich nonmonotonic behavior of the localization length ξ, particularly in two-dimensional systems, including an interaction-induced exponential enhancement of ξ for small and intermediate disorders and a strong reduction of ξ due to hopping suppression by strong interactions. In three dimensions, we identify for half filling a Mott-Hubbard-assisted Anderson localized phase existing between the metallic and the Mott-Hubbard-gapped phases. For small U there is re-entrant behavior from the Anderson localized phase to the metallic phase. For bosons, the unrestricted particle occupation number per lattice site yields a monotonic enhancement of ξ as a function of decreasing interaction, which we assume to persist until the superfluid Bose-Einstein condensate phase is entered. Besides, we study cold atomic gases expanding, by a diffusion process, in a weak random potential. We show that the density-density correlation function of the expanding gas is strongly affected by disorder and we estimate the typical size of a speckle spot, i.e., a region of enhanced or depleted density. Both a Fermi gas and a Bose-Einstein condensate (in a mean-field approach) are considered. (orig.)
Interplay of Anderson localization and strong interaction in disordered systems
Energy Technology Data Exchange (ETDEWEB)
Henseler, Peter
2010-01-15
We study the interplay of disorder localization and strong local interactions within the Anderson-Hubbard model. Taking into account local Mott-Hubbard physics and static screening of the disorder potential, the system is mapped onto an effective single-particle Anderson model, which is studied within the self-consistent theory of electron localization. For fermions, we find rich nonmonotonic behavior of the localization length {xi}, particularly in two-dimensional systems, including an interaction-induced exponential enhancement of {xi} for small and intermediate disorders and a strong reduction of {xi} due to hopping suppression by strong interactions. In three dimensions, we identify for half filling a Mott-Hubbard-assisted Anderson localized phase existing between the metallic and the Mott-Hubbard-gapped phases. For small U there is re-entrant behavior from the Anderson localized phase to the metallic phase. For bosons, the unrestricted particle occupation number per lattice site yields a monotonic enhancement of {xi} as a function of decreasing interaction, which we assume to persist until the superfluid Bose-Einstein condensate phase is entered. Besides, we study cold atomic gases expanding, by a diffusion process, in a weak random potential. We show that the density-density correlation function of the expanding gas is strongly affected by disorder and we estimate the typical size of a speckle spot, i.e., a region of enhanced or depleted density. Both a Fermi gas and a Bose-Einstein condensate (in a mean-field approach) are considered. (orig.)
Quantum transport in strongly interacting one-dimensional nanostructures
Agundez, R.R.
2015-01-01
In this thesis we study quantum transport in several one-dimensional systems with strong electronic interactions. The first chapter contains an introduction to the concepts treated throughout this thesis, such as the Aharonov-Bohm effect, the Kondo effect, the Fano effect and quantum state transfer.
Discriminative deep inelastic tests of strong interaction field theories
International Nuclear Information System (INIS)
Glueck, M.; Reya, E.
1979-02-01
It is demonstrated that recent measurements of ∫ 0 1 F 2 (x, Q 2 )dx eliminate already all strong interaction field theories except QCD. A detailed study of scaling violations of F 2 (x, Q 2 ) in QCD shows their insensitivity to the gluon content of the hadron at presently measured values of Q 2 . (orig.) [de
Two-dimensional QCD as a model for strong interaction
International Nuclear Information System (INIS)
Ellis, J.
1977-01-01
After an introduction to the formalism of two-dimensional QCD, its applications to various strong interaction processes are reviewed. Among the topics discussed are spectroscopy, deep inelastic cross-sections, ''hard'' processes involving hadrons, ''Regge'' behaviour, the existence of the Pomeron, and inclusive hadron cross-sections. Attempts are made to abstracts features useful for four-dimensional QCD phenomenology. (author)
Measurement of strong interaction parameters in antiprotonic hydrogen and deuterium
Augsburger, M A; Borchert, G L; Chatellard, D; Egger, J P; El-Khoury, P; Gorke, H; Gotta, D; Hauser, P R; Indelicato, P J; Kirch, K; Lenz, S; Siems, T; Simons, L M
1999-01-01
In the PS207 experiment at CERN, X-rays from antiprotonic hydrogen and deuterium have been measured at low pressure. The strong interaction shift and the broadening of the K/sub alpha / transition in antiprotonic hydrogen were $9 determined. Evidence was found for the individual hyperfine components of the protonium ground state. (7 refs).
A systematic study of the strong interaction with PANDA
Messchendorp, J. G.; Hosaka, A; Khemchandani, K; Nagahiro, H; Nawa, K
2011-01-01
The theory of Quantum Chromo Dynamics (QCD) reproduces the strong interaction at distances much shorter than the size of the nucleon. At larger distance scales, the generation of hadron masses and confinement cannot yet be derived from first principles on basis of QCD. The PANDA experiment at FAIR
Directory of Open Access Journals (Sweden)
Takayuki Odahara
2016-06-01
Full Text Available The data provide information in support of the research article, “Intermolecular interactions at early stage of protein/detergent particle association induced by salt/polyethylene glycol mixtures” [1]. The data regarding variation of absorption spectra is used as an indicator of the duration of Rp. viridis PRU and RC, Rb. sphaeroides RC and LH2, and Rb. capsulatus LH2 in the native state in the presence of NaCl/polyethylene glycol (PEG mixture. The data about minimum concentrations of salt and PEG whose aqueous phases are mutually separated presents information on additional influence of Tris buffer and N-octyl-β-d-glucoside on the salt–PEG phase separation.
Energy Technology Data Exchange (ETDEWEB)
He, Zhiqiang; Liu, Jinrong; Zhang, Jianbin; Zhang, Na [Inner Mongolia University of Technology, Huhhot (China)
2014-03-15
Poly-Ethylene Glycol (PEG) 300+H{sub 2}O solutions (PEGWs) has been used as a promising medium for the absorption of SO{sub 2}. We investigated the UV, FTIR, {sup 1}H-NMR, and fluorescence spectra in the absorption processes of SO{sub 2} in PEGWs to present an important absorption mechanism. Based on the spectral results, the possibility of intermolecular hydrogen bond formation by hydroxyl oxygen atom in the PEG molecule with hydrogen atom in H{sub 2}O and S…O interaction formation by the oxygen atoms in PEG with the sulfur atom in SO{sub 2} are discussed. This shows that the spectral changes may be due to the formation of -CH{sub 2}CH{sub 2}O(H)…HOH… and -CH{sub 2}-CH{sub 2}-O(CH{sub 2}-CH{sub 2}-)…HOH… in PEGWs and the formation of -CH{sub 2}CH{sub 2}OH…OSO…, and intermolecular S…O interaction between PEG and SO{sub 2} as the formation of -CH{sub 2}CH{sub 2}OCH{sub 2}CH{sub 2}O(H)…(O)S(O)… and -CH{sub 2}-CH{sub 2}-O(CH{sub 2}-CH{sub 2}-) …(O)S(O)…. The existence of these bonds benefits the absorption and desorption processes of SO{sub 2} in PEGWs.
Energy Technology Data Exchange (ETDEWEB)
Makarewicz, Jan, E-mail: jama@amu.edu.pl; Shirkov, Leonid [Faculty of Chemistry, Adam Mickiewicz University, Umultowska 89b, 61-614 Poznań (Poland)
2016-05-28
The pyridine-Ar (PAr) van der Waals (vdW) complex is studied using a high level ab initio method. Its structure, binding energy, and intermolecular vibrational states are determined from the analytical potential energy surface constructed from interaction energy (IE) values computed at the coupled cluster level of theory with single, double, and perturbatively included triple excitations with the augmented correlation consistent polarized valence double-ζ (aug-cc-pVDZ) basis set complemented by midbond functions. The structure of the complex at its global minimum with Ar at a distance of 3.509 Å from the pyridine plane and shifted by 0.218 Å from the center of mass towards nitrogen agrees well with the corresponding equilibrium structure derived previously from the rotational spectrum of PAr. The PAr binding energy D{sub e} of 392 cm{sup −1} is close to that of 387 cm{sup −1} calculated earlier at the same ab initio level for the prototypical benzene-Ar (BAr) complex. However, under an extension of the basis set, D{sub e} for PAr becomes slightly lower than D{sub e} for BAr. The ab initio vdW vibrational energy levels allow us to estimate the reliability of the methods for the determination of the vdW fundamentals from the rotational spectra. To disclose the character of the intermolecular interaction in PAr, the symmetry-adapted perturbation theory (SAPT) is employed for the analysis of different physical contributions to IE. It is found that SAPT components of IE can be approximately expressed in the binding region by only two of them: the exchange repulsion and dispersion energy. The total induction effect is negligible. The interrelations between various SAPT components found for PAr are fulfilled for a few other complexes involving aromatic molecules and Ar or Ne, which indicates that they are valid for all rare gas (Rg) atoms and aromatics.
On the strong crack-microcrack interaction problem
Gorelik, M.; Chudnovsky, A.
1992-07-01
The problem of the crack-microcrack interaction is examined with special attention given to the iterative procedure described by Chudnovsky and Kachanov (1983), Chudnovsky et al. (1984), and Horii and Nemat-Nasser (1983), which yields erroneous results as the crack tips become closer (i.e., for strong crack interaction). To understand the source of error, the traction distributions along the microcrack line on the n-th step of iteration representing the exact and asymptotic stress fields are compared. It is shown that the asymptotic solution gives a gross overestimation of the actual traction.
Ruling out a strongly interacting standard Higgs model
International Nuclear Information System (INIS)
Riesselmann, K.; Willenbrock, S.
1997-01-01
Previous work has suggested that perturbation theory is unreliable for Higgs- and Goldstone-boson scattering, at energies above the Higgs-boson mass, for relatively small values of the Higgs quartic coupling λ(μ). By performing a summation of nonlogarithmic terms, we show that perturbation theory is in fact reliable up to relatively large coupling. This eliminates the possibility of a strongly interacting standard Higgs model at energies above the Higgs-boson mass, complementing earlier studies which excluded strong interactions at energies near the Higgs-boson mass. The summation can be formulated in terms of an appropriate scale in the running coupling, μ=√(s)/e∼√(s)/2.7, so it can be incorporated easily in renormalization-group-improved tree-level amplitudes as well as higher-order calculations. copyright 1996 The American Physical Society
Atom-Pair Kinetics with Strong Electric-Dipole Interactions.
Thaicharoen, N; Gonçalves, L F; Raithel, G
2016-05-27
Rydberg-atom ensembles are switched from a weakly to a strongly interacting regime via adiabatic transformation of the atoms from an approximately nonpolar into a highly dipolar quantum state. The resultant electric dipole-dipole forces are probed using a device akin to a field ion microscope. Ion imaging and pair-correlation analysis reveal the kinetics of the interacting atoms. Dumbbell-shaped pair-correlation images demonstrate the anisotropy of the binary dipolar force. The dipolar C_{3} coefficient, derived from the time dependence of the images, agrees with the value calculated from the permanent electric-dipole moment of the atoms. The results indicate many-body dynamics akin to disorder-induced heating in strongly coupled particle systems.
The hadronic standard model for strong and electroweak interactions
International Nuclear Information System (INIS)
Raczka, R.
1993-01-01
We propose a new model for strong and electro-weak interactions. First, we review various QCD predictions for hadron-hadron and lepton-hadron processes. We indicate that the present formulation of strong interactions in the frame work of Quantum Chromodynamics encounters serious conceptual and numerical difficulties in a reliable description of hadron-hadron and lepton-hadron interactions. Next we propose to replace the strong sector of Standard Model based on unobserved quarks and gluons by the strong sector based on the set of the observed baryons and mesons determined by the spontaneously broken SU(6) gauge field theory model. We analyse various properties of this model such as asymptotic freedom, Reggeization of gauge bosons and fundamental fermions, baryon-baryon and meson-baryon high energy scattering, generation of Λ-polarization in inclusive processes and others. Finally we extend this model by electro-weak sector. We demonstrate a remarkable lepton and hadron anomaly cancellation and we analyse a series of important lepton-hadron and hadron-hadron processes such as e + + e - → hadrons, e + + e - → W + + W - , e + + e - → p + anti-p, e + p → e + p and p + anti-p → p + anti-p processes. We obtained a series of interesting new predictions in this model especially for processes with polarized particles. We estimated the value of the strong coupling constant α(M z ) and we predicted the top baryon mass M Λ t ≅ 240 GeV. Since in our model the proton, neutron, Λ-particles, vector mesons like ρ, ω, φ, J/ψ ect. and leptons are elementary most of experimentally analysed lepton-hadron and hadron-hadron processes in LEP1, LEP2, LEAR, HERA, HERMES, LHC and SSC experiments may be relatively easily analysed in our model. (author). 252 refs, 65 figs, 1 tab
A connection between the strong and weak interactions
International Nuclear Information System (INIS)
Treiman, S.B.
1989-01-01
By studying weak scattering reactions (such as pion-nucleon scattering), the author and his colleague Marvin L Goldberger became renowned in the 1950s for work on dispersion relations. As a result of their collaboration a remarkable and unexpected connection was found between strong and weak interaction quantities. Agreement with experiment was good. Work by others found the same result, but via the partially conserved axial reactor current relation between the axial current divergence and the canonical pion field. (UK)
Avetissian, Hamlet
2006-01-01
This book covers a large class of fundamental investigations into Relativistic Nonlinear Electrodynamics. It explores the interaction between charged particles and strong laser fields, mainly concentrating on contemporary problems of x-ray lasers, new type small set-up high-energy accelerators of charged particles, as well as electron-positron pair production from super powerful laser fields of relativistic intensities. It will also discuss nonlinear phenomena of threshold nature that eliminate the concurrent inverse processes in the problems of Laser Accelerator and Free Electron Laser, thus creating new opportunities for solving these problems.
The Electron-Phonon Interaction in Strongly Correlated Systems
International Nuclear Information System (INIS)
Castellani, C.; Grilli, M.
1995-01-01
We analyze the effect of strong electron-electron repulsion on the electron-phonon interaction from a Fermi-liquid point of view and show that the electron-electron interaction is responsible for vertex corrections, which generically lead to a strong suppression of the electron-phonon coupling in the v F q/ω >>1 region, while such effect is not present when v F q/ω F is the Fermi velocity and q and ω are the transferred momentum and frequency respectively. In particular the e-ph scattering is suppressed in transport properties which are dominated by low-energy-high-momentum processes. On the other hand, analyzing the stability criterion for the compressibility, which involves the effective interactions in the dynamical limit, we show that a sizable electron-phonon interaction can push the system towards a phase-separation instability. Finally a detailed analysis of these ideas is carried out using a slave-boson approach for the infinite-U three-band Hubbard model in the presence of a coupling between the local hole density and a dispersionless optical phonon. (author)
Joule-Thomson Coefficient for Strongly Interacting Unitary Fermi Gas
International Nuclear Information System (INIS)
Liao Kai; Chen Jisheng; Li Chao
2010-01-01
The Joule-Thomson effect reflects the interaction among constituent particles of macroscopic system. For classical ideal gas, the corresponding Joule-Thomson coefficient is vanishing while it is non-zero for ideal quantum gas due to the quantum degeneracy. In recent years, much attention is paid to the unitary Fermi gas with infinite two-body scattering length. According to universal analysis, the thermodynamical law of unitary Fermi gas is similar to that of non-interacting ideal gas, which can be explored by the virial theorem P = 2E/3V. Based on previous works, we further study the unitary Fermi gas properties. The effective chemical potential is introduced to characterize the nonlinear levels crossing effects in a strongly interacting medium. The changing behavior of the rescaled Joule-Thomson coefficient according to temperature manifests a quite different behavior from that for ideal Fermi gas. (general)
Experimental reduction in interaction intensity strongly affects biotic selection.
Sletvold, Nina; Ågren, Jon
2016-11-01
The link between biotic interaction intensity and strength of selection is of fundamental interest for understanding biotically driven diversification and predicting the consequences of environmental change. The strength of selection resulting from biotic interactions is determined by the strength of the interaction and by the covariance between fitness and the trait under selection. When the relationship between trait and absolute fitness is constant, selection strength should be a direct function of mean population interaction intensity. To test this prediction, we excluded pollinators for intervals of different length to induce five levels of pollination intensity within a single plant population. Pollen limitation (PL) increased from 0 to 0.77 across treatments, accompanied by a fivefold increase in the opportunity for selection. Trait-fitness covariance declined with PL for number of flowers, but varied little for other traits. Pollinator-mediated selection on plant height, corolla size, and spur length increased by 91%, 34%, and 330%, respectively, in the most severely pollen-limited treatment compared to open-pollinated plants. The results indicate that realized biotic selection can be predicted from mean population interaction intensity when variation in trait-fitness covariance is limited, and that declines in pollination intensity will strongly increase selection on traits involved in the interaction. © 2016 by the Ecological Society of America.
International Nuclear Information System (INIS)
Kouzov, A. P.; Chrysos, M.; Rachet, F.; Egorova, N. I.
2006-01-01
Collision-induced properties of two interacting molecules a and b are derived by means of a general diagrammatic method involving M molecule-molecule and N photon-molecule couplings. The method is an extension of previous graphical treatments of nonlinear optics because it exhaustively determines interaction-induced polarization mechanisms in a trustworthy and handy fashion. Here we focus on long-range intermolecular interactions. Retardation effects are neglected. A fully quantum-mechanical treatment of the molecules is made whereas second quantization for the electromagnetic field, in the nonrelativistic approximation, is implicitly applied. The collision-induced absorption, Raman, and hyper-Raman processes are viewed and studied, through guiding examples, as specific cases N=1, 2, and 3, respectively. In Raman (N=2), the standard first-order (M=1) dipole-induced dipole term of the incremental polarizability, Δα, is the result of a coupling of the two photons with distinct molecules, a and b, which perturb each other via a dipole-dipole mechanism. Rather, when the two photons interact with the same molecule, a or b, the (N=2, M=1) graphs predict the occurrence of a nonlinear polarization mechanism. The latter is expected to contribute substantially to the collision-induced Raman bands by certain molecular gases
Wernsdorfer, W.; Bhaduri, S.; Vinslava, A.; Christou, G.
2005-12-01
A Mn4 single-molecule magnet (SMM), with a well-isolated spin ground state of S=9/2 , is used as a model system to study Landau-Zener (LZ) tunneling in the presence of weak intermolecular dipolar and exchange interactions. The anisotropy constants D and B are measured with minor hysteresis loops. A transverse field is used to tune the tunnel splitting over a large range. Using the LZ and inverse LZ method, it is shown that these interactions play an important role in the tunnel rates. Three regions are identified: (i) at small transverse fields, tunneling is dominated by single tunnel transitions, (ii) at intermediate transverse fields, the measured tunnel rates are governed by reshuffling of internal fields, and (iii) at larger transverse fields, the magnetization reversal starts to be influenced by the direct relaxation process, and many-body tunnel events may occur. The hole digging method is used to study the next-nearest-neighbor interactions. At small external fields, it is shown that magnetic ordering occurs which does not quench tunneling. An applied transverse field can increase the ordering rate. Spin-spin cross-relaxations, mediated by dipolar and weak exchange interactions, are proposed to explain additional quantum steps.
Electronic transitions and intermolecular forces
International Nuclear Information System (INIS)
Hemert, M.C. van.
1981-01-01
This thesis describes two different subjects - electronic transitions and intermolecular forces - that are related mainly by the following observation: The wavenumber at which an electronic transition in an atom or molecule occurs, depends on the environment of that atom or molecule. This implies, for instance, that when a molecule becomes solvated its absorption spectrum may be shifted either to the blue or to the red side of the original gasphase spectrum. In part I attention is paid to the experimental aspects of VUV spectroscopy, both in the gasphase and in the condensed phase. In part II a series of papers are presented, dealing with the calculation of intermolecular forces (and some related topics) both for the ground state and for the excited state interactions, using different non-empirical methods. The calculations provide, among other results, a semiquantitative interpretation of the spectral blue shifts encountered in our experiments. (Auth.)
Abramov, Y A; Volkov, A; Wu, G; Coppens, P
2000-11-01
A new module interfaced to the XD programming package has been used in the evaluation of intermolecular interactions and lattice energies of the crystals of p-nitroaniline, L-asparagine monohydrate and the pentapeptide Boc-Gln-D-Iva-Hyp-Ala-Phol (Boc = butoxycarbonyl, Iva = isovaline = ethylalanine, Phol = phenylalaninol). The electrostatic interactions are evaluated with the atom-centered distributed multipoles from KRMM (kappa'-restricted multipole model) refinements, using the Buckingham expression for non-overlapping charge densities. Results for p-nitroaniline are compared with Hartree-Fock (HF), density functional (DFT) and Moller-Plesset (MP2) supermolecular calculations and with HF and DFT periodic calculations. The HF and DFT methods fail to predict the stability of the p-nitroaniline crystal but the results of the experimental charge-density approach (ECDA) are in good agreement with both MP2 interaction energies and the experimental lattice energy. ECDA results for L-asparagine monohydrate compare well with those from DFT supermolecular and periodic HF calculations. The disorder of the terminal group in the pentapeptide, which persists at the experimental temperature of 20 K, corresponds to an energy difference of only 0.35 kJ mol(-1), which is too small to be reproduced with current methods.
Nonperturbative Dynamics of Strong Interactions from Gauge/Gravity Duality
Energy Technology Data Exchange (ETDEWEB)
Grigoryan, Hovhannes [Louisiana State Univ., Baton Rouge, LA (United States)
2008-08-01
This thesis studies important dynamical observables of strong interactions such as form factors. It is known that Quantum Chromodynamics (QCD) is a theory which describes strong interactions. For large energies, one can apply perturbative techniques to solve some of the QCD problems. However, for low energies QCD enters into the nonperturbative regime, where di erent analytical or numerical tools have to be applied to solve problems of strong interactions. The holographic dual model of QCD is such an analytical tool that allows one to solve some nonperturbative QCD problems by translating them into a dual ve-dimensional theory de ned on some warped Anti de Sitter (AdS) background. Working within the framework of the holographic dual model of QCD, we develop a formalism to calculate form factors and wave functions of vector mesons and pions. As a result, we provide predictions of the electric radius, the magnetic and quadrupole moments which can be directly veri ed in lattice calculations or even experimentally. To nd the anomalous pion form factor, we propose an extension of the holographic model by including the Chern-Simons term required to reproduce the chiral anomaly of QCD. This allows us to nd the slope of the form factor with one real and one slightly o -shell photon which appeared to be close to the experimental ndings. We also analyze the limit of large virtualities (when the photon is far o -shell) and establish that predictions of the holographic model analytically coincide with those of perturbative QCD with asymptotic pion distribution amplitude. We also study the e ects of higher dimensional terms in the AdS/QCD model and show that these terms improve the holographic description towards a more realistic scenario. We show this by calculating corrections to the vector meson form factors and corrections to the observables such as electric radii, magnetic and quadrupole moments.
The hadronic standard model for strong and electroweak interactions
Energy Technology Data Exchange (ETDEWEB)
Raczka, R. [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)
1993-12-31
We propose a new model for strong and electro-weak interactions. First, we review various QCD predictions for hadron-hadron and lepton-hadron processes. We indicate that the present formulation of strong interactions in the frame work of Quantum Chromodynamics encounters serious conceptual and numerical difficulties in a reliable description of hadron-hadron and lepton-hadron interactions. Next we propose to replace the strong sector of Standard Model based on unobserved quarks and gluons by the strong sector based on the set of the observed baryons and mesons determined by the spontaneously broken SU(6) gauge field theory model. We analyse various properties of this model such as asymptotic freedom, Reggeization of gauge bosons and fundamental fermions, baryon-baryon and meson-baryon high energy scattering, generation of {Lambda}-polarization in inclusive processes and others. Finally we extend this model by electro-weak sector. We demonstrate a remarkable lepton and hadron anomaly cancellation and we analyse a series of important lepton-hadron and hadron-hadron processes such as e{sup +} + e{sup -} {yields} hadrons, e{sup +} + e{sup -} {yields} W{sup +} + W{sup -}, e{sup +} + e{sup -} {yields} p + anti-p, e + p {yields} e + p and p + anti-p {yields} p + anti-p processes. We obtained a series of interesting new predictions in this model especially for processes with polarized particles. We estimated the value of the strong coupling constant {alpha}(M{sub z}) and we predicted the top baryon mass M{sub {Lambda}{sub t}} {approx_equal} 240 GeV. Since in our model the proton, neutron, {Lambda}-particles, vector mesons like {rho}, {omega}, {phi}, J/{psi} ect. and leptons are elementary most of experimentally analysed lepton-hadron and hadron-hadron processes in LEP1, LEP2, LEAR, HERA, HERMES, LHC and SSC experiments may be relatively easily analysed in our model. (author). 252 refs, 65 figs, 1 tab.
The hadronic standard model for strong and electroweak interactions
Energy Technology Data Exchange (ETDEWEB)
Raczka, R [Soltan Inst. for Nuclear Studies, Otwock-Swierk (Poland)
1994-12-31
We propose a new model for strong and electro-weak interactions. First, we review various QCD predictions for hadron-hadron and lepton-hadron processes. We indicate that the present formulation of strong interactions in the frame work of Quantum Chromodynamics encounters serious conceptual and numerical difficulties in a reliable description of hadron-hadron and lepton-hadron interactions. Next we propose to replace the strong sector of Standard Model based on unobserved quarks and gluons by the strong sector based on the set of the observed baryons and mesons determined by the spontaneously broken SU(6) gauge field theory model. We analyse various properties of this model such as asymptotic freedom, Reggeization of gauge bosons and fundamental fermions, baryon-baryon and meson-baryon high energy scattering, generation of {Lambda}-polarization in inclusive processes and others. Finally we extend this model by electro-weak sector. We demonstrate a remarkable lepton and hadron anomaly cancellation and we analyse a series of important lepton-hadron and hadron-hadron processes such as e{sup +} + e{sup -} {yields} hadrons, e{sup +} + e{sup -} {yields} W{sup +} + W{sup -}, e{sup +} + e{sup -} {yields} p + anti-p, e + p {yields} e + p and p + anti-p {yields} p + anti-p processes. We obtained a series of interesting new predictions in this model especially for processes with polarized particles. We estimated the value of the strong coupling constant {alpha}(M{sub z}) and we predicted the top baryon mass M{sub {Lambda}{sub t}} {approx_equal} 240 GeV. Since in our model the proton, neutron, {Lambda}-particles, vector mesons like {rho}, {omega}, {phi}, J/{psi} ect. and leptons are elementary most of experimentally analysed lepton-hadron and hadron-hadron processes in LEP1, LEP2, LEAR, HERA, HERMES, LHC and SSC experiments may be relatively easily analysed in our model. (author). 252 refs, 65 figs, 1 tab.
Results from ATLAS and CMS: Strong Interactions and New Physics
AUTHOR|(INSPIRE)INSPIRE-00179262
2016-01-01
Measurements on global properties and precision results on fundamental parameters related to the Strong Interaction sector of the Standard Model of particle physics, and searches for new phenomena beyond the Standard Model, performed by the two large multi-purpose particle detectors at the Large Hadron Collider (LHC), are summarised in this review. Special attention is payed to the new data obtained at $\\sqrt{s}$ = 13~TeV in 2015, which offer a first glimpse at the large physics potential offered by the high-energy running of the LHC.
The kaon factory - towards the physics of strongly interacting systems
International Nuclear Information System (INIS)
Vogt, Erich
1988-01-01
With the advent of the standard model for quarks and leptons and unified forces there are profound new questions for the physics of strongly interacting systems: the nature of the nucleon, the physics of quark confinement, fundamental symmetries governing hadron decay and the effect of quarks and gluons on nuclear behaviour. Of the new large facilities now planned to respond to these questions the kaon factory is central. It uses very intense (∼100 μA) primary proton beams (∼30 GeV) to generate intense secondary beams of various hadrons and leptons. (author)
Strongly modified plasmon-matter interaction with mesoscopic quantum emitters
DEFF Research Database (Denmark)
Andersen, Mads Lykke; Stobbe, Søren; Søndberg Sørensen, Anders
2011-01-01
Semiconductor quantum dots (QDs) provide useful means to couple light and matter in applications such as light-harvesting1, 2 and all-solid-state quantum information processing3, 4. This coupling can be increased by placing QDs in nanostructured optical environments such as photonic crystals...... or metallic nanostructures that enable strong confinement of light and thereby enhance the light–matter interaction. It has thus far been assumed that QDs can be described in the same way as atomic photon emitters—as point sources with wavefunctions whose spatial extent can be disregarded. Here we demonstrate...
Discriminative deep inelastic tests of strong interaction field theories
International Nuclear Information System (INIS)
Glueck, M.; Reya, E.
1979-02-01
It is demonstrated that recent measurements of F 2 (x,Q 2 ) dx eliminate already all strong interaction field theories which do not include colored quarks as well as colored vector gluons. Detailed studies of scaling violations in F 2 (x,Q 2 ) cannot discriminate between a local gauge invariant theory (QCD) and one which has no local color gauge invariance, i.e. no triple-gluon coupling. This implies that all calculations on scaling violations done so far are insensitive to the gluon self-coupling, the latter might perhaps be delineated with future ep colliding beam facilities. (orig.) [de
A strong viscous–inviscid interaction model for rotating airfoils
DEFF Research Database (Denmark)
Ramos García, Néstor; Sørensen, Jens Nørkær; Shen, Wen Zhong
2014-01-01
Two-dimensional (2D) and quasi-three dimensional (3D), steady and unsteady, viscous–inviscid interactive codes capable of predicting the aerodynamic behavior of wind turbine airfoils are presented. The model is based on a viscous–inviscid interaction technique using strong coupling between...... a boundary-layer trip or computed using an en envelope transition method. Validation of the incompressible 2D version of the code is carried out against measurements and other numerical codes for different airfoil geometries at various Reynolds numbers, ranging from 0.9 ⋅ 106 to 8.2 ⋅ 106. In the quasi-3D...... version, a parametric study on rotational effects induced by the Coriolis and centrifugal forces in the boundary-layer equations shows that the effects of rotation are to decrease the growth of the boundary-layer and delay the onset of separation, hence increasing the lift coefficient slightly while...
Dynamical equilibration in strongly-interacting parton-hadron matter
Directory of Open Access Journals (Sweden)
Gorenstein M.
2011-04-01
Full Text Available We study the kinetic and chemical equilibration in 'infinite' parton-hadron matter within the Parton-Hadron-String Dynamics transport approach, which is based on a dynamical quasiparticle model for partons matched to reproduce lattice-QCD results – including the partonic equation of state – in thermodynamic equilibrium. The 'infinite' matter is simulated within a cubic box with periodic boundary conditions initialized at different baryon density (or chemical potential and energy density. The transition from initially pure partonic matter to hadronic degrees of freedom (or vice versa occurs dynamically by interactions. Different thermody-namical distributions of the strongly-interacting quark-gluon plasma (sQGP are addressed and discussed.
On the mixed phase of strongly interacting matter
International Nuclear Information System (INIS)
Suleymanov, M.K.; Abdinov, O.B.; Belashev, B.Z.; Guseynaliyev, Y.G.; Vodoplanov, A.S.
2005-01-01
Full text : The studying of the behavior of some characteristics of hadron-nuclear and nuclear-nuclear interactions as a function of the collision centrality Q is an important experimental method to get information about the changes of nuclear matter phase, because the increasing of the centrality could lead to the growth of the nuclear matter baryon density. The regime change in the behavior of some centrality depending characteristics of events is expected by the varying the Q. It would be the signal about the phase transition. This method is considered as the best tool reaching the quark-gluon plasma phase of strongly interacting matter. Some experimental results demonstrate already the existence of the regime changes in the event characteristics behavior as a function of collision centrality
Local condensate depletion at trap center under strong interactions
Yukalov, V. I.; Yukalova, E. P.
2018-04-01
Cold trapped Bose-condensed atoms, interacting via hard-sphere repulsive potentials are considered. Simple mean-field approximations show that the condensate distribution inside a harmonic trap always has the shape of a hump with the maximum condensate density occurring at the trap center. However, Monte Carlo simulations at high density and strong interactions display the condensate depletion at the trap center. The explanation of this effect of local condensate depletion at trap center is suggested in the frame of self-consistent theory of Bose-condensed systems. The depletion is shown to be due to the existence of the anomalous average that takes into account pair correlations and appears in systems with broken gauge symmetry.
Universal structure of a strongly interacting Fermi gas
Energy Technology Data Exchange (ETDEWEB)
Kuhnle, Eva; Dyke, Paul; Hoinka, Sascha; Mark, Michael; Hu Hui; Liu Xiaji; Drummond, Peter; Hannaford, Peter; Vale, Chris, E-mail: cvale@swin.edu.au [ARC Centre of Excellence for Quantum Atom Optics, Swinburne University of Technology, Hawthorn 3122 (Australia)
2011-01-10
This paper presents studies of the universal properties of strongly interacting Fermi gases using Bragg spectroscopy. We focus on pair-correlations, their relationship to the contact C introduced by Tan, and their dependence on both the momentum and temperature. We show that short-range pair correlations obey a universal law, first derived by Tan through measurements of the static structure factor, which displays a universal scaling with the ratio of the contact to the momentum C/q. Bragg spectroscopy of ultracold {sup 6}Li atoms is employed to measure the structure factor for a wide range of momenta and interaction strengths, providing broad confirmation of this universal law. We show that calibrating our Bragg spectra using the f-sum rule leads to a dramatic improvement in the accuracy of the structure factor measurement. We also measure the temperature dependence of the contact in a unitary gas and compare our results to calculations based on a virial expansion.
Pley, H W; Flaherty, K M; McKay, D B
1994-11-03
In large structured RNAs, RNA hairpins in which the strands of the duplex stem are connected by a tetraloop of the consensus sequence 5'-GNRA (where N is any nucleotide, and R is either G or A) are unusually frequent. In group I introns there is a covariation in sequence between nucleotides in the third and fourth positions of the loop with specific distant base pairs in putative RNA duplex stems: GNAA loops correlate with successive 5'-C-C.G-C base pairs in stems, whereas GNGA loops correlate with 5'-C-U.G-A. This has led to the suggestion that GNRA tetraloops may be involved in specific long-range tertiary interactions, with each A in position 3 or 4 of the loop interacting with a C-G base pair in the duplex, and G in position 3 interacting with a U-A base pair. This idea is supported experimentally for the GAAA loop of the P5b extension of the group I intron of Tetrahymena thermophila and the L9 GUGA terminal loop of the td intron of bacteriophage T4 (ref. 4). NMR has revealed the overall structure of the tetraloop for 12-nucleotide hairpins with GCAA and GAAA loops and models have been proposed for the interaction of GNRA tetraloops with base pairs in the minor groove of A-form RNA. Here we describe the crystal structure of an intermolecular complex between a GAAA tetraloop and an RNA helix. The interactions we observe correlate with the specificity of GNRA tetraloops inferred from phylogenetic studies, suggesting that this complex is a legitimate model for intramolecular tertiary interactions mediated by GNRA tetraloops in large structured RNAs.
Kulshrestha, Saurabh; Hallan, Vipin; Sharma, Anshul; Seth, Chandrika Attri; Chauhan, Anjali; Zaidi, Aijaz Asghar
2013-09-01
Coat protein (CP) and RNA3 from Prunus necrotic ringspot virus (PNRSV-rose), the most prevalent virus infecting rose in India, were characterized and regions in the coat protein important for self-interaction, during dimer formation were identified. The sequence analysis of CP and partial RNA 3 revealed that the rose isolate of PNRSV in India belongs to PV-32 group of PNRSV isolates. Apart from the already established group specific features of PV-32 group member's additional group-specific and host specific features were also identified. Presence of methionine at position 90 in the amino acid sequence alignment of PNRSV CP gene (belonging to PV-32 group) was identified as the specific conserved feature for the rose isolates of PNRSV. As protein-protein interaction plays a vital role in the infection process, an attempt was made to identify the portions of PNRSV CP responsible for self-interaction using yeast two-hybrid system. It was found (after analysis of the deletion clones) that the C-terminal region of PNRSV CP (amino acids 153-226) plays a vital role in this interaction during dimer formation. N-terminal of PNRSV CP is previously known to be involved in CP-RNA interactions, but our results also suggested that N-terminal of PNRSV CP represented by amino acids 1-77 also interacts with C-terminal (amino acids 153-226) in yeast two-hybrid system, suggesting its probable involvement in the CP-CP interaction.
Theoretical Studies of Strongly Interacting Fine Particle Systems
Fearon, Michael
Available from UMI in association with The British Library. A theoretical analysis of the time dependent behaviour of a system of fine magnetic particles as a function of applied field and temperature was carried out. The model used was based on a theory assuming Neel relaxation with a distribution of particle sizes. This theory predicted a linear variation of S_{max} with temperature and a finite intercept, which is not reflected by experimental observations. The remanence curves of strongly interacting fine-particle systems were also investigated theoretically. It was shown that the Henkel plot of the dc demagnetisation remanence vs the isothermal remanence is a useful representation of interactions. The form of the plot was found to be a reflection of the magnetic and physical microstructure of the material, which is consistent with experimental data. The relationship between the Henkel plot and the noise of a particulate recording medium, another property dependent on the microstructure, is also considered. The Interaction Field Factor (IFF), a single parameter characterising the non-linearity of the Henkel plot, is investigated. These results are consistent with a previous experimental study. Finally the results of the noise power spectral density for erased and saturated recording media are presented, so that characterisation of interparticle interactions may be carried out with greater accuracy.
Non-equilibrium magnetic interactions in strongly correlated systems
Energy Technology Data Exchange (ETDEWEB)
Secchi, A., E-mail: a.secchi@science.ru.nl [Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen (Netherlands); Brener, S.; Lichtenstein, A.I. [Institut für Theoretische Physik, Universitat Hamburg, Jungiusstraße 9, D-20355 Hamburg (Germany); Katsnelson, M.I. [Institute for Molecules and Materials, Radboud University Nijmegen, 6525 AJ Nijmegen (Netherlands)
2013-06-15
We formulate a low-energy theory for the magnetic interactions between electrons in the multi-band Hubbard model under non-equilibrium conditions determined by an external time-dependent electric field which simulates laser-induced spin dynamics. We derive expressions for dynamical exchange parameters in terms of non-equilibrium electronic Green functions and self-energies, which can be computed, e.g., with the methods of time-dependent dynamical mean-field theory. Moreover, we find that a correct description of the system requires, in addition to exchange, a new kind of magnetic interaction, that we name twist exchange, which formally resembles Dzyaloshinskii–Moriya coupling, but is not due to spin–orbit, and is actually due to an effective three-spin interaction. Our theory allows the evaluation of the related time-dependent parameters as well. -- Highlights: •We develop a theory for magnetism of strongly correlated systems out of equilibrium. •Our theory is suitable for laser-induced ultrafast magnetization dynamics. •We write time-dependent exchange parameters in terms of electronic Green functions. •We find a new magnetic interaction, a “twist exchange”. •We give general expressions for magnetic noise in itinerant-electron systems.
Czech Academy of Sciences Publication Activity Database
Řezáč, Jan; Huang, Y.; Hobza, Pavel; Beran, G. J. O.
2015-01-01
Roč. 11, č. 7 (2015), s. 3065-3079 ISSN 1549-9618 R&D Projects: GA ČR GP13-01214P; GA ČR GBP208/12/G016 Institutional support: RVO:61388963 Keywords : density functional theory * Plesset perturbation theory * noncovalent interactions * interaction energies Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.301, year: 2015
Effective interactions in strongly-coupled quantum systems
International Nuclear Information System (INIS)
Chen, J.M.C.
1986-01-01
In this thesis, they study the role of effective interactions in strongly-coupled Fermi systems where the short-range correlations introduce difficulties requiring special treatment. The correlated basis function method provides the means to incorporate the short-range correlations and generate the matrix elements of the Hamiltonian and identity operators in a nonorthogonal basis of states which are so important to their studies. In the first half of the thesis, the particle-hole channel is examined to elucidate the effects of collective excitations. Proceeding from a least-action principle, a generalization of the random-phase approximation is developed capable of describing such strongly-interacting Fermi systems as nuclei, nuclear matter, neutron-star matter, and liquid 3 He. A linear response of dynamically correlated system to a weak external perturbation is also derived based on the same framework. In the second half of the thesis, the particle-particle channel is examined to elucidate the effects of pairing in nuclear and neutron-star matter
Strong interactions and electromagnetism in low-energy hadron physics
International Nuclear Information System (INIS)
Kubis, B.
2002-10-01
In the present work, we study various aspects of the entanglement of the strong and electromagnetic interactions as it is manifest in low-energy hadron physics. In the framework of chiral perturbation theory, two aspects are investigated: the test of the structure of baryons as probed by external electromagnetic currents, and the modification of reactions mediated by the strong interactions in the presence of internal (virtual) photons. In the first part of this work, we study the electromagnetic form factors of nucleons and the ground state baryon octet, as well as strangeness form factors of the nucleon. Emphasis is put on the comparison of a new relativistic scheme for the calculation of loop diagrams to the heavy-baryon formalism, and on the convergence of higher-order corrections in both schemes. The new scheme is shown to yield both a phenomenologically more successful description of the data and better convergence behaviour. In the second part, we study isospin violation in pion-kaon scattering as mediated by virtual photon effects and the light quark mass difference. This investigation is of particular importance for the extraction of scattering lengths from measurements of lifetime and energy levels in pion-kaon atoms. The isospin breaking corrections are shown to be small and sufficiently well under control. (orig.)
Azar, R Julian; Horn, Paul Richard; Sundstrom, Eric Jon; Head-Gordon, Martin
2013-02-28
The problem of describing the energy-lowering associated with polarization of interacting molecules is considered in the overlapping regime for self-consistent field wavefunctions. The existing approach of solving for absolutely localized molecular orbital (ALMO) coefficients that are block-diagonal in the fragments is shown based on formal grounds and practical calculations to often overestimate the strength of polarization effects. A new approach using a minimal basis of polarized orthogonal local MOs (polMOs) is developed as an alternative. The polMO basis is minimal in the sense that one polarization function is provided for each unpolarized orbital that is occupied; such an approach is exact in second-order perturbation theory. Based on formal grounds and practical calculations, the polMO approach is shown to underestimate the strength of polarization effects. In contrast to the ALMO method, however, the polMO approach yields results that are very stable to improvements in the underlying AO basis expansion. Combining the ALMO and polMO approaches allows an estimate of the range of energy-lowering due to polarization. Extensive numerical calculations on the water dimer using a large range of basis sets with Hartree-Fock theory and a variety of different density functionals illustrate the key considerations. Results are also presented for the polarization-dominated Na(+)CH4 complex. Implications for energy decomposition analysis of intermolecular interactions are discussed.
Energy Technology Data Exchange (ETDEWEB)
Pashynska, Vlada, E-mail: vlada@vl.kharkov.ua [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Stepanian, Stepan [B.Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine, Lenin Ave., 47, 61103 Kharkov (Ukraine); Gömöry, Agnes; Vekey, Karoly [Institute of Organic Chemistry of Research Centre for Natural Sciences of the Hungarian Academy of Sciences, Magyar tudosok korutja, 2, Budapest H-1117 (Hungary); Adamowicz, Ludwik [University of Arizona, Department of Chemistry and Biochemistry, Tucson, AZ 85721 (United States)
2015-07-09
Highlights: • Competitive binding of artemisinin agents and aspirin with phospholipids is shown. • Complexation between the antimalarial drugs and aspirin molecules is also found. • Energetically favorable structures of the model complexes are identified by DFT. • Membranotropic activity of the studied drugs can be modified under joint usage. - Abstract: Study of intermolecular interactions of antimalarial artemisinin-type drugs and aspirin with membrane phospholipids is important in term of elucidation of the drugs activity modification under their joint usage. Combined experimental and computational study of the interaction of dihydroartemisinin, α-artemether, and artesunate with aspirin (ASP) and dipalmitoylphosphatidylcholine (DPPC) is performed by electrospray ionization (ESI) mass spectrometry and by DFT B3LYP/aug-cc-pVDZ methods. The results of the ESI investigation of systems containing artemisinin-type agent, ASP and DPPC, reveal a competition between the antimalarial agents and ASP for binding with DPPC molecules. The complexation between the antimalarial drugs and ASP is also found. Observed phenomena suggest that membranotropic activity of artemisin-type agents and aspirin is modified under their combined usage. To elucidate structure-energy characteristics of the non-covalent complexes studied the model DFT calculations are performed for dihydroartemisinin · ASP complex and complexes of the each drug with phosphatidylcholine head of DPPC in neutral and cationized forms.
Directory of Open Access Journals (Sweden)
Michael Paßens
2015-06-01
Full Text Available Disordered and uniform (2√3 × 2√3R30° superstructures of fullerenes on the Au(111 surface have been studied using scanning tunneling microscopy and spectroscopy. It is shown that the deposition and growth process of a fullerene monolayer on the Au(111 surface determine the resulting superstructure. The supply of thermal energy is of importance for the activation of a Au vacancy forming process and thus, one criterion for the selection of the respective superstructure. However, here it is depicted that a vacancy–adatom pair can be formed even at room temperature. This latter process results in C60 molecules that appear slightly more bright in scanning tunnelling microscopy images and are identified in disordered (2√3 x 2√3R30° superstructures based on a detailed structure analysis. In addition, these slightly more bright C60 molecules form uniform (2√3 x 2√3R30° superstructures, which exhibit intermolecular interactions, likely mediated by Au adatoms. Thus, vacancy–adatom pairs forming at room temperature directly affect the resulting C60 superstructure. Differential conductivity spectra reveal a lifting of the degeneracy of the LUMO and LUMO+1 orbitals in the uniform (2√3 x 2√3R30° superstructure and in addition, hybrid fullerene–Au(111 surface states suggest partly covalent interactions.
International Nuclear Information System (INIS)
Pashynska, Vlada; Stepanian, Stepan; Gömöry, Agnes; Vekey, Karoly; Adamowicz, Ludwik
2015-01-01
Highlights: • Competitive binding of artemisinin agents and aspirin with phospholipids is shown. • Complexation between the antimalarial drugs and aspirin molecules is also found. • Energetically favorable structures of the model complexes are identified by DFT. • Membranotropic activity of the studied drugs can be modified under joint usage. - Abstract: Study of intermolecular interactions of antimalarial artemisinin-type drugs and aspirin with membrane phospholipids is important in term of elucidation of the drugs activity modification under their joint usage. Combined experimental and computational study of the interaction of dihydroartemisinin, α-artemether, and artesunate with aspirin (ASP) and dipalmitoylphosphatidylcholine (DPPC) is performed by electrospray ionization (ESI) mass spectrometry and by DFT B3LYP/aug-cc-pVDZ methods. The results of the ESI investigation of systems containing artemisinin-type agent, ASP and DPPC, reveal a competition between the antimalarial agents and ASP for binding with DPPC molecules. The complexation between the antimalarial drugs and ASP is also found. Observed phenomena suggest that membranotropic activity of artemisin-type agents and aspirin is modified under their combined usage. To elucidate structure-energy characteristics of the non-covalent complexes studied the model DFT calculations are performed for dihydroartemisinin · ASP complex and complexes of the each drug with phosphatidylcholine head of DPPC in neutral and cationized forms
Relativistic strings and dual models of strong interactions
International Nuclear Information System (INIS)
Marinov, M.S.
1977-01-01
The theory of strong interactions,based on the model depicting a hardon as a one-dimentional elastic relativistic system(''string'') is considered. The relationship between this model and the concepts of quarks and partons is discussed. Presented are the principal results relating to the Veneziano dual theory, which may be considered as the consequence of the string model, and to its modifications. The classical string theory is described in detail. Attention is focused on questions of importance to the construction of the quantum theory - the Hamilton mechanisms and conformal symmetry. Quantization is described, and it is shown that it is not contradictory only in the 26-dimentional space and with a special requirement imposed on the spectrum of states. The theory of a string with a distributed spin is considered. The spin is introduced with the aid of the Grassman algebra formalism. In this case quantization is possible only in the 10-dimentional space. The strings interact by their ruptures and gluings. A method for calculating the interaction amplitudes is indicated
Directory of Open Access Journals (Sweden)
Boaz Galdino Oliveira
2009-08-01
Full Text Available We have performed a detailed theoretical study in order to understand the charge density topology of the C2H4O···C2H2 and C2H4S···C2H2 heterocyclic hydrogen-bonded complexes. Through the calculations derived from Quantum Theory of Atoms in Molecules (QTAIM, it was observed the formation of hydrogen bonds and secondary interactions. Such analysis was performed through the determination of optimized geometries at B3LYP/6-31G(d,p level of theory, by which is that QTAIM topological operators were computed, such as the electronic density ρ(r, Laplacian Ñ2ρ(r, and ellipticity ε. The examination of the hydrogen bonds has been performed through the measurement of ρ(r, Ñ2ρ(r and ε between (O···H—C and (S···H—C, whereas the secondary interaction between axial hydrogen atoms Hα and carbon of acetylene. In this insight, it was verified the existence of secondary interaction only in C2H4S···C2H2 complex because its structure is propitious to form multiple interactions.
Directory of Open Access Journals (Sweden)
Marcos Rodrigo Alborghetti
Full Text Available Cytoskeleton and protein trafficking processes, including vesicle transport to synapses, are key processes in neuronal differentiation and axon outgrowth. The human protein FEZ1 (fasciculation and elongation protein zeta 1 / UNC-76, in C. elegans, SCOCO (short coiled-coil protein / UNC-69 and kinesins (e.g. kinesin heavy chain / UNC116 are involved in these processes. Exploiting the feature of FEZ1 protein as a bivalent adapter of transport mediated by kinesins and FEZ1 protein interaction with SCOCO (proteins involved in the same path of axonal growth, we investigated the structural aspects of intermolecular interactions involved in this complex formation by NMR (Nuclear Magnetic Resonance, cross-linking coupled with mass spectrometry (MS, SAXS (Small Angle X-ray Scattering and molecular modelling. The topology of homodimerization was accessed through NMR (Nuclear Magnetic Resonance studies of the region involved in this process, corresponding to FEZ1 (92-194. Through studies involving the protein in its monomeric configuration (reduced and dimeric state, we propose that homodimerization occurs with FEZ1 chains oriented in an anti-parallel topology. We demonstrate that the interaction interface of FEZ1 and SCOCO defined by MS and computational modelling is in accordance with that previously demonstrated for UNC-76 and UNC-69. SAXS and literature data support a heterotetrameric complex model. These data provide details about the interaction interfaces probably involved in the transport machinery assembly and open perspectives to understand and interfere in this assembly and its involvement in neuronal differentiation and axon outgrowth.
Raju, Gajjela; Srinivas, Ragampeta; Santhosh Reddy, Vangala; Idris, Mohammed M.; Kamal, Ahmed; Nagesh, Narayana
2012-01-01
Studies on ligand interaction with quadruplex DNA, and their role in stabilizing the complex at concentration prevailing under physiological condition, has attained high interest. Electrospray ionization mass spectrometry (ESI-MS) and spectroscopic studies in solution were used to evaluate the interaction of PBD and TMPyP4 ligands, stoichiometry and selectivity to G-quadruplex DNA. Two synthetic ligands from PBD family, namely pyrene-linked pyrrolo[2,1-c][1,4]benzodiazepine hybrid (PBD1), mixed imine-amide pyrrolobenzodiazepine dimer (PBD2) and 5,10,15,20-tetrakis(N-methyl-4-pyridyl)porphyrin (TMPyP4) were studied. G-rich single-stranded oligonucleotide d(5′GGGGTTGGGG3′) designated as d(T2G8), from the telomeric region of Tetrahymena Glaucoma, was considered for the interaction with ligands. ESI-MS and spectroscopic methods viz., circular dichroism (CD), UV-Visible, and fluorescence were employed to investigate the G-quadruplex structures formed by d(T2G8) sequence and its interaction with PBD and TMPyP4 ligands. From ESI-MS spectra, it is evident that the majority of quadruplexes exist as d(T2G8)2 and d(T2G8)4 forms possessing two to ten cations in the centre, thereby stabilizing the complex. CD band of PBD1 and PBD2 showed hypo and hyperchromicity, on interaction with quadruplex DNA, indicating unfolding and stabilization of quadruplex DNA complex, respectively. UV-Visible and fluorescence experiments suggest that PBD1 bind externally where as PBD2 intercalate moderately and bind externally to G-quadruplex DNA. Further, melting experiments using SYBR Green indicate that PBD1 unfolds and PBD2 stabilizes the G-quadruplex complex. ITC experiments using d(T2G8) quadruplex with PBD ligands reveal that PBD1 and PBD2 prefer external/loop binding and external/intercalative binding to quadruplex DNA, respectively. From experimental results it is clear that the interaction of PBD2 and TMPyP4 impart higher stability to the quadruplex complex. PMID:22558271
Directory of Open Access Journals (Sweden)
Gajjela Raju
Full Text Available Studies on ligand interaction with quadruplex DNA, and their role in stabilizing the complex at concentration prevailing under physiological condition, has attained high interest. Electrospray ionization mass spectrometry (ESI-MS and spectroscopic studies in solution were used to evaluate the interaction of PBD and TMPyP4 ligands, stoichiometry and selectivity to G-quadruplex DNA. Two synthetic ligands from PBD family, namely pyrene-linked pyrrolo[2,1-c][1,4]benzodiazepine hybrid (PBD1, mixed imine-amide pyrrolobenzodiazepine dimer (PBD2 and 5,10,15,20-tetrakis(N-methyl-4-pyridylporphyrin (TMPyP4 were studied. G-rich single-stranded oligonucleotide d(5'GGGGTTGGGG3' designated as d(T(2G(8, from the telomeric region of Tetrahymena Glaucoma, was considered for the interaction with ligands. ESI-MS and spectroscopic methods viz., circular dichroism (CD, UV-Visible, and fluorescence were employed to investigate the G-quadruplex structures formed by d(T(2G(8 sequence and its interaction with PBD and TMPyP4 ligands. From ESI-MS spectra, it is evident that the majority of quadruplexes exist as d(T(2G(8(2 and d(T(2G(8(4 forms possessing two to ten cations in the centre, thereby stabilizing the complex. CD band of PBD1 and PBD2 showed hypo and hyperchromicity, on interaction with quadruplex DNA, indicating unfolding and stabilization of quadruplex DNA complex, respectively. UV-Visible and fluorescence experiments suggest that PBD1 bind externally where as PBD2 intercalate moderately and bind externally to G-quadruplex DNA. Further, melting experiments using SYBR Green indicate that PBD1 unfolds and PBD2 stabilizes the G-quadruplex complex. ITC experiments using d(T(2G(8 quadruplex with PBD ligands reveal that PBD1 and PBD2 prefer external/loop binding and external/intercalative binding to quadruplex DNA, respectively. From experimental results it is clear that the interaction of PBD2 and TMPyP4 impart higher stability to the quadruplex complex.
Noise in strong laser-atom interactions: Phase telegraph noise
International Nuclear Information System (INIS)
Eberly, J.H.; Wodkiewicz, K.; Shore, B.W.
1984-01-01
We discuss strong laser-atom interactions that are subjected to jump-type (random telegraph) random-phase noise. Physically, the jumps may arise from laser fluctuations, from collisions of various kinds, or from other external forces. Our discussion is carried out in two stages. First, direct and partially heuristic calculations determine the laser spectrum and also give a third-order differential equation for the average inversion of a two-level atom on resonance. At this stage a number of general features of the interaction are able to be studied easily. The optical analog of motional narrowing, for example, is clearly predicted. Second, we show that the theory of generalized Poisson processes allows laser-atom interactions in the presence of random telegraph noise of all kinds (not only phase noise) to be treated systematically, by means of a master equation first used in the context of quantum optics by Burshtein. We use the Burshtein equation to obtain an exact expression for the two-level atom's steady-state resonance fluorescence spectrum, when the exciting laser exhibits phase telegraph noise. Some comparisons are made with results obtained from other noise models. Detailed treatments of the effects ofmly jumps, or as a model of finite laser bandwidth effects, in which the laser frequency exhibits random jumps. We show that these two types of frequency noise can be distinguished in light-scattering spectra. We also discuss examples which demonstrate both temporal and spectral motional narrowing, nonexponential correlations, and non-Lorentzian spectra. Its exact solubility in finite terms makes the frequency-telegraph noise model an attractive alternative to the white-noise Ornstein-Uhlenbeck frequency noise model which has been previously applied to laser-atom interactions
Extreme states of matter in strong interaction physics an introduction
Satz, Helmut
2018-01-01
This book is a course-tested primer on the thermodynamics of strongly interacting matter – a profound and challenging area of both theoretical and experimental modern physics. Analytical and numerical studies of statistical quantum chromodynamics provide the main theoretical tool, while in experiments, high-energy nuclear collisions are the key for extensive laboratory investigations. As such, the field straddles statistical, particle and nuclear physics, both conceptually and in the methods of investigation used. The book addresses, above all, the many young scientists starting their scientific research in this field, providing them with a general, self-contained introduction that highlights the basic concepts and ideas and explains why we do what we do. Much of the book focuses on equilibrium thermodynamics: first it presents simplified phenomenological pictures, leading to critical behavior in hadronic matter and to a quark-hadron phase transition. This is followed by elements of finite temperature latti...
Stability of Dirac Liquids with Strong Coulomb Interaction.
Tupitsyn, Igor S; Prokof'ev, Nikolay V
2017-01-13
We develop and apply the diagrammatic Monte Carlo technique to address the problem of the stability of the Dirac liquid state (in a graphene-type system) against the strong long-range part of the Coulomb interaction. So far, all attempts to deal with this problem in the field-theoretical framework were limited either to perturbative or random phase approximation and functional renormalization group treatments, with diametrically opposite conclusions. Our calculations aim at the approximation-free solution with controlled accuracy by computing vertex corrections from higher-order skeleton diagrams and establishing the renormalization group flow of the effective Coulomb coupling constant. We unambiguously show that with increasing the system size L (up to ln(L)∼40), the coupling constant always flows towards zero; i.e., the two-dimensional Dirac liquid is an asymptotically free T=0 state with divergent Fermi velocity.
Screening important inputs in models with strong interaction properties
International Nuclear Information System (INIS)
Saltelli, Andrea; Campolongo, Francesca; Cariboni, Jessica
2009-01-01
We introduce a new method for screening inputs in mathematical or computational models with large numbers of inputs. The method proposed here represents an improvement over the best available practice for this setting when dealing with models having strong interaction effects. When the sample size is sufficiently high the same design can also be used to obtain accurate quantitative estimates of the variance-based sensitivity measures: the same simulations can be used to obtain estimates of the variance-based measures according to the Sobol' and the Jansen formulas. Results demonstrate that Sobol' is more efficient for the computation of the first-order indices, while Jansen performs better for the computation of the total indices.
Screening important inputs in models with strong interaction properties
Energy Technology Data Exchange (ETDEWEB)
Saltelli, Andrea [European Commission, Joint Research Centre, 21020 Ispra, Varese (Italy); Campolongo, Francesca [European Commission, Joint Research Centre, 21020 Ispra, Varese (Italy)], E-mail: francesca.campolongo@jrc.it; Cariboni, Jessica [European Commission, Joint Research Centre, 21020 Ispra, Varese (Italy)
2009-07-15
We introduce a new method for screening inputs in mathematical or computational models with large numbers of inputs. The method proposed here represents an improvement over the best available practice for this setting when dealing with models having strong interaction effects. When the sample size is sufficiently high the same design can also be used to obtain accurate quantitative estimates of the variance-based sensitivity measures: the same simulations can be used to obtain estimates of the variance-based measures according to the Sobol' and the Jansen formulas. Results demonstrate that Sobol' is more efficient for the computation of the first-order indices, while Jansen performs better for the computation of the total indices.
Towards a unified gauge theory of gravitational and strong interactions
International Nuclear Information System (INIS)
Hehl, F.W.; Sijacki, D.
1980-01-01
The space-time properties of leptons and hadrons is studied and it is found necessary to extend general relativity to the gauge theory based on the four-dimensional affine group. This group translates and deforms the tetrads of the locally Minkowskian space-time. Its conserved currents, momentum, and hypermomentum, act as sources in the two field equations of gravity. A Lagrangian quadratic in torsion and curvature allows for the propagation of two independent gauge fields: translational e-gravity mediated by the tetrad coefficients, and deformational GAMMA-gravity mediated by the connection coefficients. For macroscopic matter e-gravity coincides with general relativity up to the post-Newtonian approximation of fourth order. For microscopic matter GAMMA-gravity represents a strong Yang-Mills type interaction. In the linear approximation, for a static source, a confinement potential is found. (author)
Are Higgs particles strongly interacting(question mark)
International Nuclear Information System (INIS)
Shanker, O.
1982-02-01
The order of magnitude of Yukawa couplings in some theories with flavour violating Higgs particles is estimated. Based on these couplings, mass bounds for flavour violating Higgs particles are derived from the Ksub(L)-Ksub(S) mass difference. The Higgs particles have to be very heavy, implying that the Higgs sector quartic couplings are very large. Thus, these theories seem to require a strongly interacting Higgs sector unless one adjusts to the Higgs-fermion Yukawa couplings to within two orders of magnitude, so as to suppress the coupling of Higgs particles to the flavour-violating anti sd current. Most models with flavour violating Higgs particles have the same general features, so the conclusions are likely to hold for a wide class of models with flavour violating Higgs particles
Ion Motion in a Plasma Interacting with Strong Magnetic Fields
International Nuclear Information System (INIS)
Weingarten, A.; Grabowski, C.; Chakrabarti, N.; Maron, Y.; Fruchtmant, A.
1999-01-01
The interaction of a plasma with strong magnetic fields takes place in many laboratory experiments and astrophysical plasmas. Applying a strong magnetic field to the plasma may result in plasma displacement, magnetization, or the formation of instabilities. Important phenomena in plasma, such as the energy transport and the momentum balance, take a different form in each case. We study this interaction in a plasma that carries a short-duration (80-ns) current pulse, generating a magnetic field of up to 17 kG. The evolution of the magnetic field, plasma density, ion velocities, and electric fields are determined before and during the current pulse. The dependence of the plasma limiting current on the plasma density and composition are studied and compared to theoretical models based on the different phenomena. When the plasma collisionality is low, three typical velocities should be taken into consideration: the proton and heavier-ion Alfven velocities (v A p and v A h , respectively) and the EMHD magnetic-field penetration velocity into the plasma (v EMHD ). If both Alfven velocities are larger than v EMHD the plasma is pushed ahead of the magnetic piston and the magnetic field energy is dissipated into ion kinetic energy. If v EMHD is the largest of three velocities, the plasma become magnetized and the ions acquire a small axial momentum only. Different ion species may drift in different directions along the current lines. In this case, the magnetic field energy is probably dissipated into electron thermal energy. When vs > V EMHD > vi, as in the case of one of our experiments, ion mass separation occurs. The protons are pushed ahead of the piston while the heavier-ions become magnetized. Since the plasma electrons are unmagnetized they cannot cross the piston, and the heavy ions are probably charge-neutralized by electrons originating from the cathode that are 'born' magnetized
Kaonic atoms – studies of the strong interaction with strangeness
Directory of Open Access Journals (Sweden)
Marton J.
2014-01-01
Full Text Available The strong interaction of charged antikaons (K− with nucleons and nuclei in the low-energy regime is a fascinating topic. The antikaon plays a peculiar role in hadron physics due to the strong attraction antikaon-nucleon which is a key question for possible kaonic nuclear bound states. A rather direct experimental access to the antikaon-nucleon scattering lengths is provided by precision X-ray spectroscopy of transitions to low-lying states in light kaonic atoms like kaonic hydrogen and deuterium. After the successful completion of precision measurements on kaonic hydrogen and helium isotopes by SIDDHARTA at DAΦNE/LNF, new X-ray studies with the focus on kaonic deuterium are in preparation (SIDDHARTA2. In the future with kaonic deuterium data the antikaon-nucleon isospin-dependent scattering lengths can be extracted for the first time. An overview of the experimental results of SIDDHARTA and an outlook to future perspectives in the SIDDHARTA2 experiments in this frontier research field will be given.
Chemical Evolution of Strongly Interacting Quark-Gluon Plasma
International Nuclear Information System (INIS)
Pan, Ying-Hua; Zhang, Wei-Ning
2014-01-01
At very initial stage of relativistic heavy ion collisions a wave of quark-gluon matter is produced from the break-up of the strong color electric field and then thermalizes at a short time scale (~1 fm/c). However, the quark-gluon plasma (QGP) system is far out of chemical equilibrium, especially for the heavy quarks which are supposed to reach chemical equilibrium much late. In this paper a continuing quark production picture for strongly interacting QGP system is derived, using the quark number susceptibilities and the equation of state; both of them are from the results calculated by the Wuppertal-Budapest lattice QCD collaboration. We find that the densities of light quarks increase by 75% from the temperature T=400 MeV to T=150 MeV, while the density of strange quark annihilates by 18% in the temperature region. We also offer a discussion on how this late production of quarks affects the final charge-charge correlations
Universal contact of strongly interacting fermions at finite temperatures
Energy Technology Data Exchange (ETDEWEB)
Hu Hui; Liu Xiaji; Drummond, Peter D, E-mail: hhu@swin.edu.au, E-mail: xiajiliu@swin.edu.au, E-mail: pdrummond@swin.edu.au [ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia)
2011-03-15
The recently discovered universal thermodynamic behavior of dilute, strongly interacting Fermi gases also implies a universal structure in the many-body pair-correlation function at short distances, as quantified by the contact I. Here, we theoretically calculate the temperature dependence of this universal contact for a Fermi gas in free space and in a harmonic trap. At high temperatures above the Fermi degeneracy temperature, T{approx}>T{sub F}, we obtain a reliable non-perturbative quantum virial expansion up to third order. At low temperatures, we compare different approximate strong-coupling theories. These make different predictions, which need to be tested either by future experiments or by advanced quantum Monte Carlo simulations. We conjecture that in the universal unitarity limit, the contact or correlation decreases monotonically with increasing temperature, unless the temperature is significantly lower than the critical temperature, T<
Intermolecular and surface forces
Israelachvili, Jacob N
2011-01-01
This reference describes the role of various intermolecular and interparticle forces in determining the properties of simple systems such as gases, liquids and solids, with a special focus on more complex colloidal, polymeric and biological systems. The book provides a thorough foundation in theories and concepts of intermolecular forces, allowing researchers and students to recognize which forces are important in any particular system, as well as how to control these forces. This third edition is expanded into three sections and contains five new chapters over the previous edition.· starts fr
Xu, Jianguo; Zheng, Tingting; Le, Jingqing; Jia, Lee
2017-11-20
Occurrence and application of oligonucleotide probes have promoted great progress in the biochemical analysis field due to their unique biological and chemical properties. In this work, a long-stem shaped multifunctional molecular beacon (LS-MMB) that is responsive to a cancer-related gene, p53, is well-prepared. By designing the probe with long-paired bases at its two ends and short-paired bases between the middle region and the 3' end, the LS-MMB is intelligently endowed with the ability to recognize the target analyte, serve as the polymerization primer/template, and signal the hybridization event synchronously, which is distinctly advantageous over the traditional molecular beacons (MBs). Moreover, it is excitingly found that the LS-MMB can be employed to exert intramolecular and intermolecular interactions for strand displacement amplification (SDA) without the involvement of any assistant probes; this therapy results in a really easy and rapid sensing system that provides an extremely low background noise and high target output signal. In this case, an excellent sensitivity and specificity to detect target gene down to picomolar level and resolution to even one nucleotide variation are achieved, respectively. In addition, the application potential for real genomic DNA analysis is realized. We envision that the probe of LS-MMB can act as a universal platform for biosensing and biomedical research.
Wen, Jin; Li, Wei; Chen, Shuang; Ma, Jing
2016-08-17
Surfaces modified with a functional molecular monolayer are essential for the fabrication of nano-scale electronics or machines with novel physical, chemical, and/or biological properties. Theoretical simulation based on advanced quantum chemical and classical models is at present a necessary tool in the development, design, and understanding of the interfacial nanostructure. The nanoscale surface morphology, growth processes, and functions are controlled by not only the electronic structures (molecular energy levels, dipole moments, polarizabilities, and optical properties) of building units but also the subtle balance between intermolecular and interfacial interactions. The switchable surfaces are also constructed by introducing stimuli-responsive units like azobenzene derivatives. To bridge the gap between experiments and theoretical models, opportunities and challenges for future development of modelling of ferroelectricity, entropy, and chemical reactions of surface-supported monolayers are also addressed. Theoretical simulations will allow us to obtain important and detailed information about the structure and dynamics of monolayer modified interfaces, which will guide the rational design and optimization of dynamic interfaces to meet challenges of controlling optical, electrical, and biological functions.
Air-sea interactions during strong winter extratropical storms
Nelson, Jill; He, Ruoying; Warner, John C.; Bane, John
2014-01-01
A high-resolution, regional coupled atmosphere–ocean model is used to investigate strong air–sea interactions during a rapidly developing extratropical cyclone (ETC) off the east coast of the USA. In this two-way coupled system, surface momentum and heat fluxes derived from the Weather Research and Forecasting model and sea surface temperature (SST) from the Regional Ocean Modeling System are exchanged via the Model Coupling Toolkit. Comparisons are made between the modeled and observed wind velocity, sea level pressure, 10 m air temperature, and sea surface temperature time series, as well as a comparison between the model and one glider transect. Vertical profiles of modeled air temperature and winds in the marine atmospheric boundary layer and temperature variations in the upper ocean during a 3-day storm period are examined at various cross-shelf transects along the eastern seaboard. It is found that the air–sea interactions near the Gulf Stream are important for generating and sustaining the ETC. In particular, locally enhanced winds over a warm sea (relative to the land temperature) induce large surface heat fluxes which cool the upper ocean by up to 2 °C, mainly during the cold air outbreak period after the storm passage. Detailed heat budget analyses show the ocean-to-atmosphere heat flux dominates the upper ocean heat content variations. Results clearly show that dynamic air–sea interactions affecting momentum and buoyancy flux exchanges in ETCs need to be resolved accurately in a coupled atmosphere–ocean modeling framework.
Energy Technology Data Exchange (ETDEWEB)
Horn, Paul R., E-mail: prhorn@berkeley.edu; Mao, Yuezhi; Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Kenneth S. Pitzer Center for Theoretical Chemistry, Department of Chemistry, University of California, Berkeley, California 94720, USA and Chemical Sciences Division Lawrence Berkeley National Laboratory Berkeley, California 94720 (United States)
2016-03-21
In energy decomposition analysis of Kohn-Sham density functional theory calculations, the so-called frozen (or pre-polarization) interaction energy contains contributions from permanent electrostatics, dispersion, and Pauli repulsion. The standard classical approach to separate them suffers from several well-known limitations. We introduce an alternative scheme that employs valid antisymmetric electronic wavefunctions throughout and is based on the identification of individual fragment contributions to the initial supersystem wavefunction as determined by an energetic optimality criterion. The density deformations identified with individual fragments upon formation of the initial supersystem wavefunction are analyzed along with the distance dependence of the new and classical terms for test cases that include the neon dimer, ammonia borane, water-Na{sup +}, water-Cl{sup −}, and the naphthalene dimer.
Directory of Open Access Journals (Sweden)
Wasinee Phonsri
2017-08-01
Full Text Available The structural and magnetic properties of a range of new iron(III bis-tridentate Schiff base complexes are described with emphasis on how intermolecular structural interactions influence spin states and spin crossover (SCO in these d5 materials. Three pairs of complexes were investigated. The first pair are the neutral, heteroleptic complexes [Fe(3-OMe-SalEen(thsa] 1 and [Fe(3-MeOSalEen(3-EtOthsa] 2, where 3-R-HSalEen = (E-2-(((2-(ethylaminoethyliminomethyl-6-R-phenol and 3-R-H2thsa = thiosemicarbazone-3-R-salicylaldimine. They display spin transitions above room temperature. However, 2 shows incomplete and gradual change, while SCO in 1 is complete and more abrupt. Lower cooperativity in 2 is ascribed to the lack of π–π interactions, compared to 1. The second pair, cationic species [Fe(3-EtOSalEen2]NO3 3 and [Fe(3-EtOSalEen2]Cl 4 differ only in the counter-anion. They show partial SCO above room temperature with 3 displaying a sharp transition at 343 K. Weak hydrogen bonds from cation to Cl− probably lead to weaker cooperativity in 4. The last pair, CsH2O[Fe(3-MeO-thsa2] 5 and Cs(H2O2[Fe(5-NO2-thsa2] 6, are anionic homoleptic chelates that have different substituents on the salicylaldiminate rings of thsa2−. The Cs cations bond to O atoms of water and the ligands, in unusual ways thus forming attractive 1D and 3D networks in 5 and 6, respectively, and 5 remains HS (high spin at all temperatures while 6 remains LS (low spin. Comparisons are made to other literature examples of Cs salts of [Fe(5-R-thsa2]− (R = H and Br.
Theoretical & Experimental Research in Weak, Electromagnetic & Strong Interactions
Energy Technology Data Exchange (ETDEWEB)
Nandi, Satyanarayan [Oklahoma State Univ., Stillwater, OK (United States); Babu, Kaladi [Oklahoma State Univ., Stillwater, OK (United States); Rizatdinova, Flera [Oklahoma State Univ., Stillwater, OK (United States); Khanov, Alexander [Oklahoma State Univ., Stillwater, OK (United States); Haley, Joseph [Oklahoma State Univ., Stillwater, OK (United States)
2015-09-17
The conducted research spans a wide range of topics in the theoretical, experimental and phenomenological aspects of elementary particle interactions. Theory projects involve topics in both the energy frontier and the intensity frontier. The experimental research involves energy frontier with the ATLAS Collaboration at the Large Hadron Collider (LHC). In theoretical research, novel ideas going beyond the Standard Model with strong theoretical motivations were proposed, and their experimental tests at the LHC and forthcoming neutrino facilities were outlined. These efforts fall into the following broad categories: (i) TeV scale new physics models for LHC Run 2, including left-right symmetry and trinification symmetry, (ii) unification of elementary particles and forces, including the unification of gauge and Yukawa interactions, (iii) supersummetry and mechanisms of supersymmetry breaking, (iv) superworld without supersymmetry, (v) general models of extra dimensions, (vi) comparing signals of extra dimensions with those of supersymmetry, (vii) models with mirror quarks and mirror leptons at the TeV scale, (viii) models with singlet quarks and singlet Higgs and their implications for Higgs physics at the LHC, (ix) new models for the dark matter of the universe, (x) lepton flavor violation in Higgs decays, (xi) leptogenesis in radiative models of neutrino masses, (xii) light mediator models of non-standard neutrino interactions, (xiii) anomalous muon decay and short baseline neutrino anomalies, (xiv) baryogenesis linked to nucleon decay, and (xv) a new model for recently observed diboson resonance at the LHC and its other phenomenological implications. The experimental High Energy Physics group has been, and continues to be, a successful and productive contributor to the ATLAS experiment at the LHC. Members of the group performed search for gluinos decaying to stop and top quarks, new heavy gauge bosons decaying to top and bottom quarks, and vector-like quarks
Energy Technology Data Exchange (ETDEWEB)
Shimada, Rintaro; Hamaguchi, Hiro-o, E-mail: hhama@nctu.edu.tw [Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, 1001 University Road, Hsinchu 30010, Taiwan (China)
2014-05-28
We quantitatively interpret the recently discovered intriguing phenomenon related to resonance Hyper-Raman (HR) scattering. In resonance HR spectra of all-trans-β-carotene (β-carotene) in solution, vibrations of proximate solvent molecules are observed concomitantly with the solute β-carotene HR bands. It has been shown that these solvent bands are subject to marked intensity enhancements by more than 5 orders of magnitude under the presence of β-carotene. We have called this phenomenon the molecular-near field effect. Resonance HR spectra of β-carotene in benzene, deuterated benzene, cyclohexane, and deuterated cyclohexane have been measured precisely for a quantitative analysis of this effect. The assignments of the observed peaks are made by referring to the infrared, Raman, and HR spectra of neat solvents. It has been revealed that infrared active and some Raman active vibrations are active in the HR molecular near-field effect. The observed spectra in the form of difference spectra (between benzene/deuterated benzene and cyclohexane/deuterated cyclohexane) are quantitatively analyzed on the basis of the extended vibronic theory of resonance HR scattering. The theory incorporates the coupling of excited electronic states of β-carotene with the vibrations of a proximate solvent molecule through solute–solvent dipole–dipole and dipole–quadrupole interactions. It is shown that the infrared active modes arise from the dipole–dipole interaction, whereas Raman active modes from the dipole–quadrupole interaction. It is also shown that vibrations that give strongly polarized Raman bands are weak in the HR molecular near-field effect. The observed solvent HR spectra are simulated with the help of quantum chemical calculations for various orientations and distances of a solvent molecule with respect to the solute. The observed spectra are best simulated with random orientations of the solvent molecule at an intermolecular distance of 10 Å.
Effective Field Theories and Strong Interactions. Final Technical Report
International Nuclear Information System (INIS)
Fleming, Sean
2011-01-01
The framework of Effective Field Theories (EFTs) allows us to describe strong interactions in terms of degrees of freedom relevant to the energy regimes of interest, in the most general way consistent with the symmetries of QCD. Observables are expanded systematically in powers of M lo /M hi , where M lo (M hi ) denotes a low-(high-)energy scale. This organizational principle is referred to as 'power counting'. Terms of increasing powers in the expansion parameter are referred to as leading order (LO), next-to-leading order (NLO), etc. Details of the QCD dynamics not included explicitly are encoded in interaction parameters, or 'low-energy constants' (LECs), which can in principle be calculated from an explicit solution of QCD - for example via lattice simulations- but can also be determined directly from experimental data. QCD has an intrinsic scale M QCD ≅ 1 GeV, at which the QCD coupling constant α s (M QCD ) becomes large and the dynamics becomes non-perturbative. As a consequence M QCD sets the scale for the masses of most hadrons, such as the nucleon mass m N ≅ 940 MeV. EFTs can roughly be divided into two categories: those that can be matched onto QCD in perturbation theory, which we call high-energy EFTs, and those that cannot be matched perturbatively, which we call low-energy EFTs. In high-energy EFTs, M QCD typically sets the low-energy scale, and all the dynamics associated with this scale reside in matrix elements of EFT operators. These non-perturbative matrix elements are the LECs and are also referred to as long-distance contributions. Each matrix element is multiplied by a short-distance coefficient, which contains the dynamics from the high scale M hi . Since M hi >> M QCD , α s (M hi ) hi ∼ M Q , the heavy-quark mass, and in addition to M QCD there are low scales associated with the typical relative momentum ∼ M Q v and energy ∼ M Q v 2 of the heavy quarks. Depending on the sizes of M Q and the heavy-quark velocity v these scales can
Energy Technology Data Exchange (ETDEWEB)
Witte, Jonathon [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Neaton, Jeffrey B. [Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States); Kavli Energy Nanosciences Institute at Berkeley, Berkeley, California 94720 (United States); Head-Gordon, Martin, E-mail: mhg@cchem.berkeley.edu [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)
2016-05-21
With the aim of systematically characterizing the convergence of common families of basis sets such that general recommendations for basis sets can be made, we have tested a wide variety of basis sets against complete-basis binding energies across the S22 set of intermolecular interactions—noncovalent interactions of small and medium-sized molecules consisting of first- and second-row atoms—with three distinct density functional approximations: SPW92, a form of local-density approximation; B3LYP, a global hybrid generalized gradient approximation; and B97M-V, a meta-generalized gradient approximation with nonlocal correlation. We have found that it is remarkably difficult to reach the basis set limit; for the methods and systems examined, the most complete basis is Jensen’s pc-4. The Dunning correlation-consistent sequence of basis sets converges slowly relative to the Jensen sequence. The Karlsruhe basis sets are quite cost effective, particularly when a correction for basis set superposition error is applied: counterpoise-corrected def2-SVPD binding energies are better than corresponding energies computed in comparably sized Dunning and Jensen bases, and on par with uncorrected results in basis sets 3-4 times larger. These trends are exhibited regardless of the level of density functional approximation employed. A sense of the magnitude of the intrinsic incompleteness error of each basis set not only provides a foundation for guiding basis set choice in future studies but also facilitates quantitative comparison of existing studies on similar types of systems.
Phases of strongly-interacting matter with functional methods
International Nuclear Information System (INIS)
Mitter, M.
2012-01-01
Non-perturbative aspects of strongly-interacting matter, in particular at non-vanishing temperatures, are investigated with functional methods. The consequences of confinement in terms of a linearly rising static quark potential arising from an infrared singular quark 4-point function are studied. Such a singularity is only consistent for a specific color structure and implies the existence of similar singularities in special color structures of n-point functions with n>3. A simple explanation for Casimir scaling is found within this mechanism of confinement.The deconfinement transition of fundamentally charged scalar and quark matter is investigated in terms of center symmetry. Novel dual order parameters are introduced that can be obtained from the corresponding matter propagators. In the case of quark matter the new order parameter compares well with the dual chiral condensate, with the advantage that no regularization is necessary even at non-vanishing quark masses.The influence of the axial anomaly on the chiral transition is studied in terms of a 't Hooft determinant with quarks and mesons as effective degrees of freedom in the functional renormalization group. In the case of two quark flavors, the calculated temperature dependent determinant results in a decrease of the anomalous eta'-mass close to the chiral transition temperature. This is connected to a partial Z(2) restoration at the chiral transition instead of the restoration of full axial U(1). With 2+1 quark flavors and a temperature independent 't Hooft term, the chiral transition is found to be of second order with three dimensional O(4) critical exponents in the limit of vanishing up and down quark mass, whereas a first-order transition is seen without U(1) violation. (author) [de
Intermolecular Interactions at high pressure
DEFF Research Database (Denmark)
Eikeland, Espen Zink
2016-01-01
In this project high-pressure single crystal X-ray diffraction has been combined with quantitative energy calculations to probe the energy landscape of three hydroquinone clathrates enclosing different guest molecules. The simplicity of the hydroquinone clathrate structures together with their st...
The colours of strong interaction; L`interaction forte sous toutes ses couleurs
Energy Technology Data Exchange (ETDEWEB)
NONE
1996-12-31
The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)
The colours of strong interaction; L`interaction forte sous toutes ses couleurs
Energy Technology Data Exchange (ETDEWEB)
NONE
1995-12-31
The aim of this session is to draw a consistent framework about the different ways to consider strong interaction. A large part is dedicated to theoretical work and the latest experimental results obtained at the first electron collider HERA are discussed. (A.C.)
Jin, Shouwen; Wang, Daqi
2014-05-01
Eight crystalline organic acid-base adducts derived from alkane bridged bis(N-benzimidazole) and organic acids (2,4,6-trinitrophenol, p-nitrobenzoic acid, m-nitrobenzoic acid, 3,5-dinitrobenzoic acid, 5-sulfosalicylic acid and oxalic acid) were prepared and characterized by X-ray diffraction analysis, IR, mp, and elemental analysis. Of the eight compounds five are organic salts (1, 4, 6, 7 and 8) and the other three (2, 3, and 5) are cocrystals. In all of the adducts except 1 and 8, the ratio of the acid and the base is 2:1. All eight supramolecular assemblies involve extensive intermolecular classical hydrogen bonds as well as other noncovalent interactions. The role of weak and strong noncovalent interactions in the crystal packing is ascertained. These weak interactions combined, all the complexes displayed 3D framework structure. The results presented herein indicate that the strength and directionality of the classical N+-H⋯O-, O-H⋯O, and O-H⋯N hydrogen bonds (ionic or neutral) and other nonbonding associations between acids and ditopic benzimidazoles are sufficient to bring about the formation of cocrystals or organic salts.
Properties of hot and dense strongly interacting matter
Energy Technology Data Exchange (ETDEWEB)
Almasi, Gabor Andras
2017-06-19
In this thesis we consider effective models of quantum chromodynamics to learn about the chiral- and deconfinement phase transitions. In Chapter 1 we review basic properties of strongly interacting matter and the foundations of finite temperature field theory. We review furthermore the nonperturbative functional renormalization group (FRG) approach. In Chapter 2 we introduce the quark-meson (QM) model and its extensions including the Polyakov-loop variables and repulsive vector interactions between quarks. We then discuss features of the model both in the mean-field approximation and in the renormalization group treatment. A novel method to solve the renormalization group equations based on the Chebyshev polynomials is presented at the end of the chapter. In Chapter 3 the scaling behavior of the order parameter at the chiral phase transition is studied within effective models. We explore universal and nonuniversal structures near the critical point. These include the scaling functions, the leading corrections to scaling and the corresponding size of the scaling window as well as their dependence on an external symmetry breaking field. We consider two models in the mean-field approximation, the QM and the Polyakov-loop-extended quark-meson (PQM) models, and compare their critical properties with a purely bosonic theory, the O(N) linear sigma model in the N → ∞ limit. In these models the order parameter scaling function is found analytically using the high temperature expansion of the thermodynamic potential. The effects of a gluonic background on the nonuniversal scaling parameters are studied within the PQM model. Furthermore, numerical calculations of the scaling function and the scaling window are performed in the QM model using the FRG. Chapter 4 contains a study of the critical properties of net-baryon-number fluctuations at the chiral restoration transition in a medium at finite temperature and net baryon density. The chiral dynamics of quantum
Two Methods For Simulating the Strong-Strong Beam-Beam Interaction in Hadron Colliders
International Nuclear Information System (INIS)
Warnock, Robert L.
2002-01-01
We present and compare the method of weighted macro particle tracking and the Perron-Frobenius operator technique for simulating the time evolution of two beams coupled via the collective beam-beam interaction in 2-D and 4-D (transverse) phase space. The coherent dipole modes, with and without lattice nonlinearities and external excitation, are studied by means of the Vlasov-Poisson system
Lawrence, Jon; Yang, En-Che; Edwards, Rachel; Olmstead, Marilyn M; Ramsey, Chris; Dalal, Naresh S; Gantzel, Peter K; Hill, Stephen; Hendrickson, David N
2008-03-17
structure splittings for complex 3. This behavior is thought to be due to the onset of short-range magnetic correlations/coherences between molecules caused by weak intermolecular magnetic exchange interactions.
Intensities and strong interaction attenuation of kaonic x-rays
Backenstoss, Gerhard; Koch, H; Povel, H P; Schwitter, A; Tauscher, Ludwig
1974-01-01
Relative intensities of numerous kaonic X-ray transitions have been measured for the elements C, P, S, and Cl, from which level widths due to the strong K-nucleus absorption have been determined. From these and earlier published data, optical potential parameters have been derived and possible consequences on the nuclear matter distribution are discussed. (10 refs).
Interaction of neutral particles with strong laser fields
Energy Technology Data Exchange (ETDEWEB)
Meuren, Sebastian; Keitel, Christoph H.; Di Piazza, Antonino [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)
2013-07-01
Since the invention of the laser in the 1960s the experimentally available field strengths have continuously increased. The current peak intensity record is 2 x 10{sup 22} W/cm{sup 2} and next generation facilities such as ELI, HiPER and XCELS plan to reach even intensities of the order of 10{sup 24} W/cm{sup 2}. Thus, modern laser facilities are a clean source for very strong external electromagnetic fields and promise new and interesting high-energy physics experiments. In particular, strong laser fields could be used to test non-linear effects in quantum field theory. Earlier we have investigated how radiative corrections modify the coupling of a charged particle inside a strong plane-wave electromagnetic background field. However, a charged particle couples already at tree level to electromagnetic radiation. Therefore, we have now analyzed how the coupling between neutral particles and radiation is affected by a very strong plane-wave electromagnetic background field, when loop corrections are taken into account. In particular, the case of neutrinos is discussed.
Low energy p anti p strong interactions: theoretical perspective
International Nuclear Information System (INIS)
Dover, C.B.
1985-01-01
Several of the frontier problems in low energy nucleon-antinucleon phenomenology are addressed. Spin observables and dynamical selection rules in N anti N annihilation are used as examples of phenomena which offer particularly strong constraints on theoretical models, formulated either in terms of meson and baryon exchange or as effective operators in a non-perturbative quark-gluon picture. 24 refs
On the strong influence of molecular interactions over large distances
Pfennig, Andreas
2018-03-01
Molecular-dynamics simulations of liquid water show deterministic chaos, i.e. an intentionally introduced molecular position shift of an individual molecule increases exponentially by a factor of 10 in 0.23 ps. This is a Lyaponov instability. As soon as it reaches molecular scale, the direction of the resulting shift in molecular motions is unpredictable. The influence of any individual distant particle on an observed molecule will be minute, but the effect will quickly increase to molecular scale and beyond due to this exponential growth. Consequently, any individual particle in the universe will affect the behavior of any molecule within at most 33 ps after the interaction reaches it. A larger distance of the faraway particle does not decrease the influence on an observed molecule, but the effect reaches molecular scale only some ps later. Thus in evaluating the interactions, nearby and faraway molecules have to be equally accounted for. The consequences of this quickly reacting network of interactions on universal scale are fundamental. Even in a strictly deterministic view, molecular behavior is principally unpredictable, and thus has to be regarded random. Corresponding statements apply for any particles interacting. This result leads to a fundamental rethinking of the structure of interactions of molecules and particles as well as the behavior of reality.
Strong-coupling interaction in high-Tc superconductors
International Nuclear Information System (INIS)
Ray, D.K.
1991-01-01
Extensive experimental and theoretical work have been done to understand the mechanisms of superconductivity. Until 1986 when Bednorz and Muller discovered superconductivity in the copper oxide perovskite, the principal mechanism was found to be electron-phonon interaction and the characteristics of superconductivity vary depending on the strength of the electron-phonon interaction and the electronic structure. The essential characteristic of these conventional superconductors could be divided into two groups: wide band metals with low density of states N(E F ) at the Fermi energy E F and a rather weak electron-phonon coupling V obeying the universal characteristics of the BCS theory and narrow d band metals, compounds, and alloys with high values of N(E F ), electron-phonon coupling V and non negligible Coulomb interaction between the electrons. In this paper a short summary and the important results of these theories are discussed. The inherent limitations of these theories based on electron-phonon interaction will be discussed. The authors indicate the major characteristics of the new superconductors. These characteristics are difficult to explain on the basis of either the conventional electron-phonon theory or theories based on magnetic interactions alone
Magnetic dynamics of weakly and strongly interacting hematite nanoparticles
DEFF Research Database (Denmark)
Hansen, Mikkel Fougt; Bender Koch, Christian; Mørup, Steen
2000-01-01
The magnetic dynamics of two differently treated samples of hematite nanoparticles from the same batch with a particle size of about 20 nm have been studied by Mossbauer spectroscopy. The dynamics of the first sample, in which the particles are coated and dispersed in water, is in accordance with...... down by interparticle interactions and a magnetically split spectrum is retained at room temperature. The temperature variation or the magnetic hyperfine field, corresponding to different quantiles in the hyperfine field distribution, can be consistently described by a mean field model...... for "superferromagnetism" in which the magnetic anisotropy is included. The coupling between the particles is due to exchange interactions and the interaction strength can be accounted for by just a few exchange bridges between surface atoms in neighboring crystallites....
Magnetic interactions in strongly correlated systems: Spin and orbital contributions
Energy Technology Data Exchange (ETDEWEB)
Secchi, A., E-mail: a.secchi@science.ru.nl [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands); Lichtenstein, A.I. [Universitat Hamburg, Institut für Theoretische Physik, Jungiusstraße 9, D-20355 Hamburg (Germany); Katsnelson, M.I. [Radboud University, Institute for Molecules and Materials, 6525 AJ Nijmegen (Netherlands)
2015-09-15
We present a technique to map an electronic model with local interactions (a generalized multi-orbital Hubbard model) onto an effective model of interacting classical spins, by requiring that the thermodynamic potentials associated to spin rotations in the two systems are equivalent up to second order in the rotation angles, when the electronic system is in a symmetry-broken phase. This allows to determine the parameters of relativistic and non-relativistic magnetic interactions in the effective spin model in terms of equilibrium Green’s functions of the electronic model. The Hamiltonian of the electronic system includes, in addition to the non-relativistic part, relativistic single-particle terms such as the Zeeman coupling to an external magnetic field, spin–orbit coupling, and arbitrary magnetic anisotropies; the orbital degrees of freedom of the electrons are explicitly taken into account. We determine the complete relativistic exchange tensors, accounting for anisotropic exchange, Dzyaloshinskii–Moriya interactions, as well as additional non-diagonal symmetric terms (which may include dipole–dipole interaction). The expressions of all these magnetic interactions are determined in a unified framework, including previously disregarded features such as the vertices of two-particle Green’s functions and non-local self-energies. We do not assume any smallness in spin–orbit coupling, so our treatment is in this sense exact. Finally, we show how to distinguish and address separately the spin, orbital and spin–orbital contributions to magnetism, providing expressions that can be computed within a tight-binding Dynamical Mean Field Theory.
Strongly-Interacting Fermi Gases in Reduced Dimensions
2015-11-16
12 2012): 0. doi: 10.1103/PhysRevA.86.063625 Allan Adams , Lincoln D Carr, Thomas Schäfer, Peter Steinberg, John E Thomas. Strongly correlated quantum...Physics (NCSU, 2013) Received Book Chapter TOTAL: PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: Discipline Willie Ong 1.00 Chingyun Cheng 0.50...PERCENT_SUPPORTEDNAME FTE Equivalent: Total Number: NAME Total Number: NAME Total Number: Willie Ong 1 PERCENT_SUPPORTEDNAME FTE Equivalent: Total
Coulomb plus strong interaction bound states - momentum space numerical solutions
International Nuclear Information System (INIS)
Heddle, D.P.; Tabakin, F.
1985-01-01
The levels and widths of hadronic atoms are calculated in momentum space using an inverse algorithm for the eigenvalue problem. The Coulomb singularity is handled by the Lande substraction method. Relativistic, nonlocal, complex hadron-nucleus interactions are incorporated as well as vacuum polarization and finite size effects. Coordinate space wavefunctions are obtained by employing a Fourier Bessel transformation. (orig.)
Strong light-matter interaction in graphene - Invited talk
DEFF Research Database (Denmark)
Xiao, Sanshui
Graphene has attracted lots of attention due to its remarkable electronic and optical properties, thus providing great promise in photonics and optoelectronics. However, the performance of these devices is generally limited by the weak light-matter interaction in graphene. The combination...
Strongly anisotropic RKKY interaction in monolayer black phosphorus
Zare, Moslem; Parhizgar, Fariborz; Asgari, Reza
2018-06-01
We theoretically study the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in two-dimensional black phosphorus, phosphorene. The RKKY interaction enhances significantly for the low levels of hole doping owing to the nearly valence flat band. Remarkably, for the hole-doped phosphorene, the highest RKKY interaction occurs when two impurities located along the zigzag direction and it tends to a minimum value with changing the direction from the zigzag to the armchair direction. We show that the interaction is highly anisotropic and the magnetic ground-state of two magnetic adatoms can be tuned by changing the rotational configuration of impurities. Owing to the anisotropic band dispersion, the oscillatory behavior with respect to the angle of the rotation and the distance of two magnetic impurities, R is well-described by sin (2kF R) , where the Fermi wavelength kF changes in different directions. We also find that the tail of the RKKY oscillations falls off as 1 /R2 at large distances.
Interaction of a strong vortex with decaying turbulence
International Nuclear Information System (INIS)
Terry, P.W.
1988-01-01
The evolution of a localized, axially symmetric vortex under the action of shear stresses associated with decaying two-dimensional turbulent vorticity which is inhomogeneous in the presence of the vortex is studied analytically. For a vortex which is sufficiently strong relative to the coefficient of turbulent eddy viscosity, it is shown that turbulent fluctuations in the vortex interior and diffusion of coherent vorticity by the turbulence localize to the vortex periphery. It is also found that the coefficient of diffusion is small compared to the coefficient of eddy viscosity. 8 refs
The hard-sphere model of strongly interacting fermion systems
Mecca, Angela
2016-01-01
The formalism based on Correlated Basis Functions (CBF) and the cluster-expansion technique has been recently employed to derive an effective interaction from a realistic nuclear Hamiltonian. One of the main objectives of the work described in this Thesis is establishing the accuracy of this novel approach--that allows to combine the flexibility of perturbation theory in the basis of eigenstates of the noninteracting system with a realistic description of short-range correlations in coordinat...
Bose-Einstein-condensed gases with arbitrary strong interactions
International Nuclear Information System (INIS)
Yukalov, V. I.; Yukalova, E. P.
2006-01-01
Bose-condensed gases are considered with an effective interaction strength varying in the whole range of the values between zero and infinity. The consideration is based on the usage of a representative statistical ensemble for Bose systems with broken global gauge symmetry. Practical calculations are illustrated for a uniform Bose gas at zero temperature, employing a self-consistent mean-field theory, which is both conserving and gapless
Colliding winds: Interaction regions with strong heat conduction
International Nuclear Information System (INIS)
Imamura, J.N.; Chevalier, R.A.
1984-01-01
The interaction of fast stellar wind with a slower wind from previous mass loss gives rise to a region of hot, shocked gas. We obtain self-similar solutions for the interaction region under the assumptions of constant mass loss rate and wind velocity for the two winds, conversion of energy in the shock region, and either isothermal electrons and adiabatic ions or isothermal electrons ad ions in the shocked region. The isothermal assumption is intended to show the effects of strog heat conduction. The solutions have no heat conduction through the shock waves and assume that the electron and ion temperatures are equilibriated in the shock waves. The one-temperature isothermal solutions have nearly constant density through the shocked region, while the two-temperature solutions are intermediate between the one-temperature adiabatic and isothermal solutions. In the two-temperature solutions, the ion temperature goes to zero at the point where the gas comoves with the shocked region and the density peaks at this point. The solution may qualitatively describe the effects of heat conduction on interaction regions in the solar wind. It will be important to determine whether the assumption of no thermal waves outside the shocked region applies to shock waves in the solar wind
Strongly-interacting mirror fermions at the LHC
Directory of Open Access Journals (Sweden)
Triantaphyllou George
2017-01-01
Full Text Available The introduction of mirror fermions corresponding to an interchange of leftwith right-handed fermion quantum numbers of the Standard Model can lead to a model according to which the BEH mechanism is just an effective manifestation of a more fundamental theory while the recently-discovered Higgs-like particle is composite. This is achieved by a non-abelian gauge symmetry encompassing three mirror-fermion families strongly coupled at energies near 1 TeV. The corresponding non-perturbative dynamics lead to dynamical mirror-fermion masses between 0.14 - 1.2 TeV. Furthermore, one expects the formation of composite states, i.e. “mirror mesons”, with masses between 0.1 and 3 TeV. The number and properties of the resulting new degrees of freedom lead to a rich and interesting phenomenology, part of which is analyzed in the present work.
Interaction of Energetic Particles with Discontinuities Upstream of Strong Shocks
Malkov, Mikhail; Diamond, Patrick
2008-11-01
Acceleration of particles in strong astrophysical shocks is known to be accompanied and promoted by a number of instabilities which are driven by the particles themselves. One of them is an acoustic (also known as Drury's) instability driven by the pressure gradient of accelerated particles upstream. The generated sound waves naturally steepen into shocks thus forming a shocktrain. Similar magnetoacoustic or Alfven type structures may be driven by pick-up ions, for example. We consider the solutions of kinetic equation for accelerated particles within the shocktrain. The accelerated particles are assumed to be coupled to the flow by an intensive pitch-angle scattering on the self-generated Alfven waves. The implications for acceleration and confinement of cosmic rays in this shock environment will be discussed.
Spin effects in strong-field laser-electron interactions
International Nuclear Information System (INIS)
Ahrens, S; Bauke, H; Müller, T-O; Villalba-Chávez, S; Müller, C
2013-01-01
The electron spin degree of freedom can play a significant role in relativistic scattering processes involving intense laser fields. In this contribution we discuss the influence of the electron spin on (i) Kapitza-Dirac scattering in an x-ray laser field of high intensity, (ii) photo-induced electron-positron pair production in a strong laser wave and (iii) multiphoton electron-positron pair production on an atomic nucleus. We show that in all cases under consideration the electron spin can have a characteristic impact on the process properties and their total probabilities. To this end, spin-resolved calculations based on the Dirac equation in the presence of an intense laser field are performed. The predictions from Dirac theory are also compared with the corresponding results from the Klein-Gordon equation.
Strong delayed interactive effects of metal exposure and warming
DEFF Research Database (Denmark)
Debecker, Sara; Dinh, Khuong Van; Stoks, Robby
2017-01-01
’ ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and lowlatitude populations. By integrating these mechanisms...... into a single study, we could identify two novel patterns. First, during exposure zinc did not affect survival, whereas it induced mild to moderate postexposure mortality in the larval stage and at metamorphosis, and very strongly reduced adult lifespan. This severe delayed effect across metamorphosis...... was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies...
A non-linear theory of strong interactions
International Nuclear Information System (INIS)
Skyrme, T.H.R.
1994-01-01
A non-linear theory of mesons, nucleons and hyperons is proposed. The three independent fields of the usual symmetrical pseudo-scalar pion field are replaced by the three directions of a four-component field vector of constant length, conceived in an Euclidean four-dimensional isotopic spin space. This length provides the universal scaling factor, all other constants being dimensionless; the mass of the meson field is generated by a φ 4 term; this destroys the continuous rotation group in the iso-space, leaving a 'cubic' symmetry group. Classification of states by this group introduces quantum numbers corresponding to isotopic spin and to 'strangeness'; one consequences is that, at least in elementary interactions, charge is only conserved module 4. Furthermore, particle states have not a well-defined parity, but parity is effectively conserved for meson-nucleon interactions. A simplified model, using only two dimensions of space and iso-space, is considered further; the non-linear meson field has solutions with particle character, and an indication is given of the way in which the particle field variables might be introduced as collective co-ordinates describing the dynamics of these particular solutions of the meson field equations, suggesting a unified theory based on the meson field alone. (author). 7 refs
Strong Constraints on Aerosol-Cloud Interactions from Volcanic Eruptions
Malavelle, Florent F.; Haywood, Jim M.; Jones, Andy; Gettelman, Andrew; Clarisse, Lieven; Bauduin, Sophie; Allan, Richard P.; Karset, Inger Helene H.; Kristjansson, Jon Egill; Oreopoulos, Lazaros;
2017-01-01
Aerosols have a potentially large effect on climate, particularly through their interactions with clouds, but the magnitude of this effect is highly uncertain. Large volcanic eruptions produce sulfur dioxide, which in turn produces aerosols; these eruptions thus represent a natural experiment through which to quantify aerosol-cloud interactions. Here we show that the massive 2014-2015 fissure eruption in Holuhraun, Iceland, reduced the size of liquid cloud droplets - consistent with expectations - but had no discernible effect on other cloud properties. The reduction in droplet size led to cloud brightening and global-mean radiative forcing of around minus 0.2 watts per square metre for September to October 2014. Changes in cloud amount or cloud liquid water path, however, were undetectable, indicating that these indirect effects, and cloud systems in general, are well buffered against aerosol changes. This result will reduce uncertainties in future climate projections, because we are now able to reject results from climate models with an excessive liquid-water-path response.
Light and neutron scattering study of strongly interacting ionic micelles
International Nuclear Information System (INIS)
Degiorgio, V.; Corti, M.; Piazza, R.
1989-01-01
Dilute solutions of ionic micelles formed by biological glycolipids (gangliosides) have been investigated at various ionic strengths by static and dynamic light scaterring and by small-angle neutron scattering. The size and shape of the micelle is not appreciably affected by the added salt concentration in the range 0-100 mM NaCL. From the measured intensity of scattered light we derive the electric charge Z of the micelle by fitting the data to a theoretical calculation which uses a screened Coulomb potential for the intermicellar interaction, and the hypernetted chain approximation for the calculation of the radial distribution function. The correlation function derived from dynamic light scattering shows the long time contribution typical of concentrated polydisperse systems (author). 15 refs.; 6 figs
Natural cold baryogenesis from strongly interacting electroweak symmetry breaking
Energy Technology Data Exchange (ETDEWEB)
Konstandin, Thomas; Servant, Géraldine, E-mail: tkonstan@cern.ch, E-mail: geraldine.servant@cern.ch [CERN Physics Department, Theory Division, CH-1211 Geneva 23 (Switzerland)
2011-07-01
The mechanism of ''cold electroweak baryogenesis'' has been so far unpopular because its proposal has relied on the ad-hoc assumption of a period of hybrid inflation at the electroweak scale with the Higgs acting as the waterfall field. We argue here that cold baryogenesis can be naturally realized without the need to introduce any slow-roll potential. Our point is that composite Higgs models where electroweak symmetry breaking arises via a strongly first-order phase transition provide a well-motivated framework for cold baryogenesis. In this case, reheating proceeds by bubble collisions and we argue that this can induce changes in Chern-Simons number, which in the presence of new sources of CP violation commonly lead to baryogenesis. We illustrate this mechanism using as a source of CP violation an effective dimension-six operator which is free from EDM constraints, another advantage of cold baryogenesis compared to the standard theory of electroweak baryogenesis. Our results are general as they do not rely on any particular UV completion but only on a stage of supercooling ended by a first-order phase transition in the evolution of the universe, which can be natural if there is nearly conformal dynamics at the TeV scale. Besides, baryon-number violation originates from the Standard Model only.
Natural Cold Baryogenesis from Strongly Interacting Electroweak Symmetry Breaking
Konstandin, Thomas
2011-01-01
The mechanism of "cold electroweak baryogenesis" has been so far unpopular because its proposal has relied on the ad-hoc assumption of a period of hybrid inflation at the electroweak scale with the Higgs acting as the waterfall field. We argue here that cold baryogenesis can be naturally realized without the need to introduce any slow-roll potential. Our point is that composite Higgs models where electroweak symmetry breaking arises via a strongly first-order phase transition provide a well-motivated framework for cold baryogenesis. In this case, reheating proceeds by bubble collisions and we argue that this can induce changes in Chern-Simons number, which in the presence of new sources of CP violation commonly lead to baryogenesis. We illustrate this mechanism using as a source of CP violation an effective dimension-six operator which is free from EDM constraints, another advantage of cold baryogenesis compared to the standard theory of electroweak baryogenesis. Our results are general as they do not rely on...
Natural cold baryogenesis from strongly interacting electroweak symmetry breaking
International Nuclear Information System (INIS)
Konstandin, Thomas; Servant, Géraldine
2011-01-01
The mechanism of ''cold electroweak baryogenesis'' has been so far unpopular because its proposal has relied on the ad-hoc assumption of a period of hybrid inflation at the electroweak scale with the Higgs acting as the waterfall field. We argue here that cold baryogenesis can be naturally realized without the need to introduce any slow-roll potential. Our point is that composite Higgs models where electroweak symmetry breaking arises via a strongly first-order phase transition provide a well-motivated framework for cold baryogenesis. In this case, reheating proceeds by bubble collisions and we argue that this can induce changes in Chern-Simons number, which in the presence of new sources of CP violation commonly lead to baryogenesis. We illustrate this mechanism using as a source of CP violation an effective dimension-six operator which is free from EDM constraints, another advantage of cold baryogenesis compared to the standard theory of electroweak baryogenesis. Our results are general as they do not rely on any particular UV completion but only on a stage of supercooling ended by a first-order phase transition in the evolution of the universe, which can be natural if there is nearly conformal dynamics at the TeV scale. Besides, baryon-number violation originates from the Standard Model only
Strongly coupled semiclassical plasma: interaction model and some properties
International Nuclear Information System (INIS)
Baimbetov, N.F.; Bekenov, N.A.
1999-01-01
In the report a fully ionized strongly coupled hydrogen plasma is considered. The density number is considered within range n=n e =n i ≅(10 21 -2·10 25 )sm -3 , and the temperature domian is T≅(5·10 4 -10 6 ) K. The coupling parameter Γ is defined by Γ=e 2 /αk B T, where k B is the Boltzmann constant and e is electrical charge, α=(3/4πn) 1/3 is the average distance between the particles (Wigner-Seitz radius). The dimensionless density parameter r s =α/α B is given in terms of the Bohr radius α B =ℎ 2 /me 2 ∼0.529·10 - 8 sm. The degeneracy parameter for the electron was defined by the ratio between the thermal energy k B T and the Fermi energy E F :Θ=k B T/E F ∼0.54·r s /Γ. The intermediate temperature-density region, where Γ≥1; Θ≅1; T>13.6 eV is examined. A semiclassical effective potential which account for the short-range, quantum diffraction and symmetry effects of charge carriers screening
Desensitization of metastable intermolecular composites
Busse, James R [South Fork, CO; Dye, Robert C [Los Alamos, NM; Foley, Timothy J [Los Alamos, NM; Higa, Kelvin T [Ridgecrest, CA; Jorgensen, Betty S [Jemez Springs, NM; Sanders, Victor E [White Rock, NM; Son, Steven F [Los Alamos, NM
2011-04-26
A method to substantially desensitize a metastable intermolecular composite material to electrostatic discharge and friction comprising mixing the composite material with an organic diluent and removing enough organic diluent from the mixture to form a mixture with a substantially putty-like consistency, as well as a concomitant method of recovering the metastable intermolecular composite material.
Alkorta, Ibon; Elguero, José; Elguero, Eric
2017-11-01
1125 X-ray structures of nitroxide free radicals presenting intermolecular hydrogen bonds have been reported in the Cambridge Structural Database. We will report in this paper a qualitative and quantitative analysis of these bonds. The observation in some plots of an excluded region was statistically analyzed using convex hull and kernel smooting methodologies. A theoretical study at the MP2 level with different basis has been carried out indicating that the nitronyl nitroxide radicals (five electrons) lie just in between nitroso compounds (four electrons) and amine N-oxides (six electrons) as far as hydrogen-bond basicity is concerned.
Gray solitons in a strongly interacting superfluid Fermi gas
International Nuclear Information System (INIS)
Spuntarelli, Andrea; Pieri, Pierbiagio; Strinati, Giancarlo C; Carr, Lincoln D
2011-01-01
The Bardeen-Cooper-Schrieffer (BCS) to Bose-Einstein condensate (BEC) crossover problem is solved for stationary gray solitons via the Boguliubov-de Gennes equations at zero temperature. These crossover solitons exhibit a localized notch in the gap and a characteristic phase difference across the notch for all interaction strengths, from BEC to BCS regimes. However, they do not follow the well-known Josephson-like sinusoidal relationship between velocity and phase difference except in the far BEC limit: at unitarity, the velocity has a nearly linear dependence on phase difference over an extended range. For a fixed phase difference, the soliton is of nearly constant depth from the BEC limit to unitarity and then grows progressively shallower into the BCS limit, and on the BCS side, Friedel oscillations are apparent in both gap amplitude and phase. The crossover soliton appears fundamentally in the gap; we show, however, that the density closely follows the gap, and the soliton is therefore observable. We develop an approximate power-law relationship to express this fact: the density of gray crossover solitons varies as the square of the gap amplitude in the BEC limit and as a power of about 1.5 at unitarity.
Exact tensor network ansatz for strongly interacting systems
Zaletel, Michael P.
It appears that the tensor network ansatz, while not quite complete, is an efficient coordinate system for the tiny subset of a many-body Hilbert space which can be realized as a low energy state of a local Hamiltonian. However, we don't fully understand precisely which phases are captured by the tensor network ansatz, how to compute their physical observables (even numerically), or how to compute a tensor network representation for a ground state given a microscopic Hamiltonian. These questions are algorithmic in nature, but their resolution is intimately related to understanding the nature of quantum entanglement in many-body systems. For this reason it is useful to compute the tensor network representation of various `model' wavefunctions representative of different phases of matter; this allows us to understand how the entanglement properties of each phase are expressed in the tensor network ansatz, and can serve as test cases for algorithm development. Condensed matter physics has many illuminating model wavefunctions, such as Laughlin's celebrated wave function for the fractional quantum Hall effect, the Bardeen-Cooper-Schrieffer wave function for superconductivity, and Anderson's resonating valence bond ansatz for spin liquids. This thesis presents some results on exact tensor network representations of these model wavefunctions. In addition, a tensor network representation is given for the time evolution operator of a long-range one-dimensional Hamiltonian, which allows one to numerically simulate the time evolution of power-law interacting spin chains as well as two-dimensional strips and cylinders.
Energy Technology Data Exchange (ETDEWEB)
Novoa, J.J.; Whangbo, Myung-Hwan [North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemistry; Williams, J.M. [Argonne National Lab., IL (United States)
1991-12-31
On the basis of SCF and single reference MP2 calculations, the full potential energy surface of the interaction between CH{sub 4} and CN{sup {minus}} was studied using extended basis sets of up to near Hartree-Fock limit quality. Colinear arrangements C-N{sup {minus}}{hor_ellipsis}H-CH{sub 3} and N-C{sup {minus}}{hor_ellipsis}H-CH{sub 3} are found to be the only two energy minima. The binding energies of these two structures are calculated to be 2.5 and 2.1 kcal/mol, respectively, at the MP2 level. The full vibrational analyses of two structures show a red shift of about 30 cm{sup {minus}1} for the v{sub s} C-H stretching.
Hyperspherical Treatment of Strongly-Interacting Few-Fermion Systems in One Dimension
DEFF Research Database (Denmark)
Volosniev, A. G.; Fedorov, D. V.; Jensen, A. S.
2015-01-01
We examine a one-dimensional two-component fermionic system in a trap, assuming that all particles have the same mass and interact through a strong repulsive zero-range force. First we show how a simple system of three strongly interacting particles in a harmonic trap can be treated using...
Search for strongly interacting massive particles using semiconductor detectors on the ground
International Nuclear Information System (INIS)
Derbin, A.V.; Egorov, A.I.; Bakhlanov, S.V.; Muratova, V.N.
1999-01-01
Using signals from recoil nucleus in semiconductor detectors, search for strongly interacting massive particles, as a possible candidate for dark matter, is continued. Experimental installation and the experimental results are given. New limits on the possible masses and cross sections of strongly interacting massive particles are presented [ru
Directory of Open Access Journals (Sweden)
Claudio N. Cavasotto
2003-04-01
Full Text Available Abstract: Correlation effects on the change of 1J(CH couplings in model systems I:NCH...H2O and II:CH4...H2O as a function of the H...O distance are discussed. RPA and SOPPA results follow a similar trend in system II. In system I RPA values decrease monotonously as the H...O distance decreases, while SOPPA ones exhibit flat maximum near equilibrium. Such different behavior is ascribed to the ÃÂ€-transmitted component. Intermolecular couplings at the equilibrium geometry of I are analyzed by means of the CLOPPA approach. The larger absolute value of 2hJ(CO compared to 1hJ(HO is found to arise from contributions involving a vacant LMO localized in the C-H...O moiety.
Raschka, Sebastian; Wolf, Alex J; Bemister-Buffington, Joseph; Kuhn, Leslie A
2018-04-01
Understanding how proteins encode ligand specificity is fascinating and similar in importance to deciphering the genetic code. For protein-ligand recognition, the combination of an almost infinite variety of interfacial shapes and patterns of chemical groups makes the problem especially challenging. Here we analyze data across non-homologous proteins in complex with small biological ligands to address observations made in our inhibitor discovery projects: that proteins favor donating H-bonds to ligands and avoid using groups with both H-bond donor and acceptor capacity. The resulting clear and significant chemical group matching preferences elucidate the code for protein-native ligand binding, similar to the dominant patterns found in nucleic acid base-pairing. On average, 90% of the keto and carboxylate oxygens occurring in the biological ligands formed direct H-bonds to the protein. A two-fold preference was found for protein atoms to act as H-bond donors and ligand atoms to act as acceptors, and 76% of all intermolecular H-bonds involved an amine donor. Together, the tight chemical and geometric constraints associated with satisfying donor groups generate a hydrogen-bonding lock that can be matched only by ligands bearing the right acceptor-rich key. Measuring an index of H-bond preference based on the observed chemical trends proved sufficient to predict other protein-ligand complexes and can be used to guide molecular design. The resulting Hbind and Protein Recognition Index software packages are being made available for rigorously defining intermolecular H-bonds and measuring the extent to which H-bonding patterns in a given complex match the preference key.
Raschka, Sebastian; Wolf, Alex J.; Bemister-Buffington, Joseph; Kuhn, Leslie A.
2018-02-01
Understanding how proteins encode ligand specificity is fascinating and similar in importance to deciphering the genetic code. For protein-ligand recognition, the combination of an almost infinite variety of interfacial shapes and patterns of chemical groups makes the problem especially challenging. Here we analyze data across non-homologous proteins in complex with small biological ligands to address observations made in our inhibitor discovery projects: that proteins favor donating H-bonds to ligands and avoid using groups with both H-bond donor and acceptor capacity. The resulting clear and significant chemical group matching preferences elucidate the code for protein-native ligand binding, similar to the dominant patterns found in nucleic acid base-pairing. On average, 90% of the keto and carboxylate oxygens occurring in the biological ligands formed direct H-bonds to the protein. A two-fold preference was found for protein atoms to act as H-bond donors and ligand atoms to act as acceptors, and 76% of all intermolecular H-bonds involved an amine donor. Together, the tight chemical and geometric constraints associated with satisfying donor groups generate a hydrogen-bonding lock that can be matched only by ligands bearing the right acceptor-rich key. Measuring an index of H-bond preference based on the observed chemical trends proved sufficient to predict other protein-ligand complexes and can be used to guide molecular design. The resulting Hbind and Protein Recognition Index software packages are being made available for rigorously defining intermolecular H-bonds and measuring the extent to which H-bonding patterns in a given complex match the preference key.
Extension of lattice cluster theory to strongly interacting, self-assembling polymeric systems.
Freed, Karl F
2009-02-14
A new extension of the lattice cluster theory is developed to describe the influence of monomer structure and local correlations on the free energy of strongly interacting and self-assembling polymer systems. This extension combines a systematic high dimension (1/d) and high temperature expansion (that is appropriate for weakly interacting systems) with a direct treatment of strong interactions. The general theory is illustrated for a binary polymer blend whose two components contain "sticky" donor and acceptor groups, respectively. The free energy is determined as an explicit function of the donor-acceptor contact probabilities that depend, in turn, on the local structure and both the strong and weak interactions.
He-, Ne-, and Ar-phosgene intermolecular potential energy surfaces
DEFF Research Database (Denmark)
Munteanu, Cristian R.; Henriksen, Christian; Felker, Peter M.
2013-01-01
Using the CCSD(T) model, we evaluated the intermolecular potential energy surfaces of the He-, Ne-, and Ar-phosgene complexes. We considered a representative number of intermolecular geometries for which we calculated the corresponding interaction energies with the augmented (He complex) and doub...... of the complexes, providing valuable results for future experimental investigations. Comparing our results to those previously available for other phosgene complexes, we suggest that the results for Cl2-phosgene should be revised....
Zhen, Jun-Ping; Wei, Xiao-Chun; Shi, Wen-Jing; Huang, Zhu-Yuan; Jin, Bo; Zhou, Yu-Kun
2017-11-14
In order to examine the origin of the drug action and design new DNA/RNA-targeted drugs, the cooperativity effect involving drug-DNA/RNA intermolecular interaction in ketoprofen⋯cytosine⋯H 2 O ternary system were investigated by the B3LYP, B3LYP-D3, and MP2 methods with the 6-311++G(2d,p) basis set. The thermodynamic cooperativity was also evaluated at 310.15 K. The N-H⋯O, O-H⋯O, O-H⋯N, C-H⋯N, and C-H⋯O H bonds coexist in ternary complexes. The intermolecular interactions obtained by B3LYP-D3 are close to those calculated by MP2. The steric effects and van der Waals interactions have little influence on the cooperativity effects. The anti-cooperativity effect in ket⋯cyt⋯H 2 O is far more notable than the cooperativity effect, and the stability of the cyclic structure with anti-cooperativity effect is higher than that of the linear structure with cooperativity effect, as is confirmed by the AIM (atoms in molecules) and RDG (reduced density gradient) analysis. Thus, it can be inferred that, in the presence of H 2 O, the anti-cooperativity effect plays a dominant role in the drug-DNA/RNA interaction, and the nature of the hydration in the binding of drugs to DNA/RNA bases is the H-bonding anti-cooperativity effect. Furthermore, the drug always links simultaneously with DNA/RNA base and H 2 O, and only in this way can the biological activity of drugs play a role. In most cases, the enthalpy change is the major factor driving the cooperativity, as is different from most of biomacromolecule complexes.
Deducing T, C, and P invariance for strong interactions in topological particle theory
International Nuclear Information System (INIS)
Jones, C.E.
1985-01-01
It is shown here how the separate discrete invariances [time reversal (T), charge conjugation (C), and parity (P)] in strong interactions can be deduced as consequences of other S-matrix requirements in topological particle theory
Effects of interaction imbalance in a strongly repulsive one-dimensional Bose gas
DEFF Research Database (Denmark)
Barfknecht, Rafael Emilio; Zinner, Nikolaj Thomas; Foerster, Angela
2018-01-01
We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction and population imbalances. We calculate...
International Nuclear Information System (INIS)
Riedl, S.
2009-01-01
This thesis explores the dynamics in an ultracold strongly interacting Fermi gas. Therefore we perform measurements on collective excitation modes and rotational properties of the gas. The strongly interacting gas is realized using an optically trapped Fermi gas of 6 Li atoms, where the interactions can be tuned using a broad Feshbach resonance. Our measurements allow to test the equation of state of the gas, study the transition from hydrodynamic to collisionless behavior, reveal almost ideal hydrodynamic behavior in the nonsuperfluid phase, investigate the lifetime of angular momentum, and show superfluidity through the quenching of the moment of inertia. (author)
Relativistic stability of interacting Fermi gas in a strong magnetic field
International Nuclear Information System (INIS)
Wang Lilin; Tian Jincheng; Men Fudian; Zhang Yipeng
2013-01-01
By means of the single particle energy spectrum of weak interaction between fermions and Poisson formula, the thermodynamic potential function of relativistic Fermi gas in a strong magnetic field is derived. Based on this, we obtained the criterion of stability for the system. The results show that the mechanics stability of a Fermi gas with weak interacting is influenced by the interacting. While the magnetic field is able to regulate the influence and the relativistic effect has almost no effect on it. (authors)
Effects of Interaction Imbalance in a Strongly Repulsive One-Dimensional Bose Gas
Barfknecht, R. E.; Foerster, A.; Zinner, N. T.
2018-05-01
We calculate the spatial distributions and the dynamics of a few-body two-component strongly interacting Bose gas confined to an effectively one-dimensional trapping potential. We describe the densities for each component in the trap for different interaction and population imbalances. We calculate the time evolution of the system and show that, for a certain ratio of interactions, the minority population travels through the system as an effective wave packet.
Gauge unification of basic forces particularly of gravitation with strong interactions
International Nuclear Information System (INIS)
Salam, A.
1977-01-01
Corresponding to the two known types of gauge theories, Yang-Mills with spin-one mediating particles and Einstein Weyl with spin-two mediating particles, it is speculated that two distinct gauge unifications of the basic forces appear to be taking place. One is the familiar Yang-Mills unification of weak and electromagnetic forces with the strong. The second is the less familiar gauge unification of gravitation with spin-two tensor-dominated aspects of strong interactions. It is proposed that there are strongly interacting spin-two strong gravitons obeying Einstein's equations, and their existence gives a clue to an understanding of the (partial) confinement of quarks, as well as of the concept of hadronic temperature, through the use of Schwarzschild de-Sitter-like partially confining solitonic solutions of the strong gravity Einstein equation
Wave, particle-family duality and the conservation of discrete symmetries in strong interaction
International Nuclear Information System (INIS)
van der Spuy, E.
1984-01-01
This paper starts from a nonlinear fermion field equation of motion with a strongly coupled self-interaction. Nonperturbative quark solutions of the equation of motion are constructed in terms of a Reggeized infinite component free spinor field. Such a field carries a family of strongly interacting unstable compounds lying on a Regge locus in the analytically continued quark spin. Such a quark field is naturally confined and also possesses the property of asymptotic freedom. Furthermore, the particular field self-regularizes the interactions and naturally breaks the chiral invariance of the equation of motion. We show why and how the existence of such a strongly coupled solution and its particle-family, wave duality forces a change in the field equation of motion such that it conserves C,P,T, although its individual interaction terms are of V-A and thus C,P nonconserving type
Strong coupling of two interacting excitons confined in a nanocavity-quantum dot system
International Nuclear Information System (INIS)
Cardenas, Paulo C; RodrIguez, Boris A; Quesada, Nicolas; Vinck-Posada, Herbert
2011-01-01
We present a study of the strong coupling between radiation and matter, considering a system of two quantum dots, which are in mutual interaction and interact with a single mode of light confined in a semiconductor nanocavity. We take into account dissipative mechanisms such as the escape of the cavity photons, decay of the quantum dot excitons by spontaneous emission, and independent exciton pumping. It is shown that the mutual interaction between the dots can be measured off-resonance only if the strong coupling condition is reached. Using the quantum regression theorem, a reasonable definition of the dynamical coupling regimes is introduced in terms of the complex Rabi frequency. Finally, the emission spectrum for relevant conditions is presented and compared with the above definition, demonstrating that the interaction between the excitons does not affect the strong coupling.
arXiv Recent results from the strong interactions program of NA61/SHINE
Pulawski, Szymon
2017-01-01
The NA61/SHINE experiment studies hadron production in hadron+hadron, hadron+nucleus and nucleus+nucleus collisions. The strong interactions program has two main purposes: study the properties of the onset of deconfinement and search for the signatures of the critical point of strongly interacting matter. This aim is pursued by performing a two-dimensional scan of the phase diagram by varying the energy/momentum (13A-158A GeV/c) and the system size (p+p, Be+Be, Ar+Sc, Xe+La) of the collisions. This publication reviews recent results from p+p, Be+Be and Ar+Sc interactions. Measured particle spectra are discussed and compared to NA49 results from Pb+Pb collisions. The results illustrate the progress towards scanning the phase diagram of strongly interacting matter.
Experimental and numerical study of the strong interaction between wakes of cylindrical obstacles
International Nuclear Information System (INIS)
Brun, Ch.
1998-01-01
In the context of thermal-hydraulics of nuclear reactors, strong interaction between wakes is encountered in the bottom of reactor vessels where control and measurement rods of variable size and disposition interact with the overall wakes generated in these flow zones. This study deals with the strong interaction between two wakes developed downstream of two parallel cylinders with a small spacing. The analysis focusses on the effect of the Reynolds regime which controls the equilibrium between the inertia and viscosity forces of the fluid and influences the large scale behaviour of the flow with the development of hydrodynamic instabilities and turbulence. The document is organized as follows: the characteristic phenomena of wakes formation downstream of cylindrical obstacles are recalled in the first chapter (single cylinder, interaction between two tubes, case of a bundle of tubes perpendicular to the flow). The experimental setup (hydraulic loop, velocity and pressure measurement instrumentation) and the statistical procedures applied to the signals measured are detailed in chapters 2 and 3. Chapter 4 is devoted to the experimental study of the strong interaction between two tubes. Laser Doppler velocity measurements in the wakes close to cylinders and pressure measurements performed on tube walls are reported in this chapter. In chapter 5, a 2-D numerical simulation of two typical cases of interaction (Re = 1000 and Re = 5000) is performed. In the last chapter, a more complex application of strong interactions inside and downstream of a bunch of staggered tubes is analyzed experimentally for equivalent Reynolds regimes. (J.S.)
Strong excitonic interactions in the oxygen K-edge of perovskite oxides
Energy Technology Data Exchange (ETDEWEB)
Tomita, Kota; Miyata, Tomohiro [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan); Olovsson, Weine [Department of Physics, Chemistry and Biology (IFM), Linköping University, SE-581 83 Linköping (Sweden); Mizoguchi, Teruyasu, E-mail: teru@iis.u-tokyo.ac.jp [Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro, Tokyo 153-8505 (Japan)
2017-07-15
Excitonic interactions of the oxygen K-edge electron energy-loss near-edge structure (ELNES) of perovskite oxides, CaTiO{sub 3}, SrTiO{sub 3}, and BaTiO{sub 3}, together with reference oxides, MgO, CaO, SrO, BaO, and TiO{sub 2}, were investigated using a first-principles Bethe–Salpeter equation calculation. Although the transition energy of oxygen K-edge is high, strong excitonic interactions were present in the oxygen K-edge ELNES of the perovskite oxides, whereas the excitonic interactions were negligible in the oxygen K-edge ELNES of the reference compounds. Detailed investigation of the electronic structure suggests that the strong excitonic interaction in the oxygen K-edge ELNES of the perovskite oxides is caused by the directionally confined, low-dimensional electronic structure at the Ti–O–Ti bonds. - Highlights: • Excitonic interaction in oxygen-K edge is investigated. • Strong excitonic interaction is found in the oxygen-K edge of perovskite oxides. • The strong excitonic interaction is ascribed to the low-dimensional and confined electronic structure.
Structural modeling and intermolecular correlation of liquid chlorine dioxide
International Nuclear Information System (INIS)
Ogata, Norio; Hironori, Shimakura; Kawakita, Yukinobu; Ohara, Yukoji; Kohara, Shinji; Takeda, Shinichi
2009-01-01
Chlorine dioxide (ClO 2 ) is water-soluble yellow gas at room temperature. It has long been used as a disinfectant of tap water and various commodities owing to its strong oxidizing activity against various microbial proteins. The oxidizing activity is believed to be due to the presence of unpaired electron in its molecular orbital. Despite wealth of physicochemical studies of gaseous ClO 2 , little is known about liquid ClO 2 , especially about fine molecular structure and intermolecular interactions of liquid ClO 2 . The purpose of this study is to elucidate the fine structure and intermolecular orientations of ClO 2 molecules in its liquid state using a high-energy X-ray diffraction technique. The measurements of liquid ClO 2 were carried out at -50 to 0 degree Celsius using a two-axis diffractometer installed at the BL04B2 beamline in the third-generation synchrotron radiation facility SPring-8 (Hyogo, Japan). The incident X-ray beamline was 113.4 keV in energy and 0.1093 Armstrong in wavelength from a Si(111) monochromator with the third harmonic reflection. Liquid ClO 2 held in a quartz capillary tube was placed in a temperature-controlled vacuum chamber. We obtained a structure factor S(Q) to a range of Q = 0.3-30 Amstrong -1 and a pair distribution function g(r) upon Fourier transform of the S(Q). The total g(r) showed peaks at 1.46, 2.08, 2.48, 3.16 and 4.24 Armstrong. From intramolecular bond lengths of 1.46 Armstrong for Cl-O and 2.48 Armstrong for O-O, O-Cl-O bond angle was estimated to be 116.1 degrees. Peaks at 3.16 and 4.24 Armstrong in the total g(r) strongly indicate presence of specific intermolecular orientations of ClO 2 molecules that are distinct from those observed as a dimer in the solid phase ClO 2 . This view was further supported by molecular simulation using a reverse Monte Carlo method (RMC). (author)
Quantum magnetism in strongly interacting one-dimensional spinor Bose systems
DEFF Research Database (Denmark)
Salami Dehkharghani, Amin; Volosniev, A. G.; Lindgren, E. J.
2015-01-01
-range inter-species interactions much larger than their intra-species interactions and show that they have novel energetic and magnetic properties. In the strongly interacting regime, these systems have energies that are fractions of the basic harmonic oscillator trap quantum and have spatially separated......Strongly interacting one-dimensional quantum systems often behave in a manner that is distinctly different from their higher-dimensional counterparts. When a particle attempts to move in a one-dimensional environment it will unavoidably have to interact and 'push' other particles in order...... ground states with manifestly ferromagnetic wave functions. Furthermore, we predict excited states that have perfect antiferromagnetic ordering. This holds for both balanced and imbalanced systems, and we show that it is a generic feature as one crosses from few- to many-body systems....
Institute of Scientific and Technical Information of China (English)
无
2008-01-01
The densities (ρ), ultrasonic speeds (v), and refractive indices (n) of binary mixtures of styrene (STY)with m-, o-, or p-xylene, including those of their pure liquids, were measured over the entire composition range at the temperatures 298.15, 303.15, 308.15, and 313.15 K. The excess volumes (VE), deviations in isentropic compressibilities(△ks), acoustic impedances (△Z), and refractive indices (△n) were calculated from the experimental data. Partial molar volumes (V0φ,2) and partial molar isentropic compressibilities (K0φ,2) of xylenes in styrene have also been calculated. The derived functions, namely, VE, △ks, △Z, △n, V0φ,2, and K0φ,2 were used to have a better understanding of the intermolecular interactions occurring between the component molecules of the present liquid mixtures. The variations of these parameters suggest that the interactions between styrene and o-, m-, or p-xylene molecules follow the sequences: p-xylene＞o-xylene＞m-xylene. Apart from using density data for the calculation of VE, excess molar volumes were also estimated using refractive index data. Furthermore, several refractive index mixing rules have been used to estimate the refractive indices of the studied liquid mixtures theoretically. Overall, the computed and measured data were interpreted in terms of interactions between the mixing components.
Spectral asymptotics of a strong δ′ interaction supported by a surface
International Nuclear Information System (INIS)
Exner, Pavel; Jex, Michal
2014-01-01
Highlights: • Attractive δ ′ interactions supported by a smooth surface are considered. • Surfaces can be either infinite and asymptotically planar, or compact and closed. • Spectral asymptotics is determined by the geometry of the interaction support. - Abstract: We derive asymptotic expansion for the spectrum of Hamiltonians with a strong attractive δ ′ interaction supported by a smooth surface in R 3 , either infinite and asymptotically planar, or compact and closed. Its second term is found to be determined by a Schrödinger type operator with an effective potential expressed in terms of the interaction support curvatures
Wave, particle-family duality and the conservation of discrete symmetries in strong interaction
International Nuclear Information System (INIS)
Van der Spuy, E.
1984-01-01
This paper starts from a nonlinear fermion field equation of motion with a strongly coupled selfinteraction. Nonperturbative quark solutions of the equation of motion are constructed in terms of a Reggeized infinite component free spinor field. Such a field carries a family of strongly interacting unstable compounds lying on a Regge locus in the analytically continued quark spin. Such a quark field is naturally confined and also possesses the property of asymptotic freedom. Furthermore the particular field selfregularizes the interactions and naturally breaks the chiral invariance of the equation of motion. We show why and how the existence of such a strongly coupled solution and its particle-family, wave duality forces a change in the field equation of motion such that it conserves C, P, T although its individual interaction terms are of V - A and thus C, P nonconserving type
International Nuclear Information System (INIS)
Chan, J.; DePorcel, L.; Dixon, L.
1997-06-01
This conference explored the role of the strong interaction in the physics of hadrons and partons. The Institute attracted 239 physicists from 16 countries to hear lectures on the underlying theory of Quantum Chromodynamics, modern theoretical calculational techniques, and experimental investigation of the strong interaction as it appears in various phenomena. Different regimes in which one can calculate reliably in QCD were addressed in series of lectures on perturbation theory, lattice gauge theories, and heavy quark expansions. Studies of QCD in hadron-hadron collisions, electron-positron annihilation, and electron-proton collisions all give differing perspectives on the strong interaction--from low-x to high-Q 2 . Experimental understanding of the production and decay of heavy quarks as well as the lighter meson states has continued to evolve over the past years, and these topics were also covered at the School. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database
Strong field QED in lepton colliders and electron/laser interactions
Hartin, Anthony
2018-05-01
The studies of strong field particle physics processes in electron/laser interactions and lepton collider interaction points (IPs) are reviewed. These processes are defined by the high intensity of the electromagnetic fields involved and the need to take them into account as fully as possible. Thus, the main theoretical framework considered is the Furry interaction picture within intense field quantum field theory. In this framework, the influence of a background electromagnetic field in the Lagrangian is calculated nonperturbatively, involving exact solutions for quantized charged particles in the background field. These “dressed” particles go on to interact perturbatively with other particles, enabling the background field to play both macroscopic and microscopic roles. Macroscopically, the background field starts to polarize the vacuum, in effect rendering it a dispersive medium. Particles encountering this dispersive vacuum obtain a lifetime, either radiating or decaying into pair particles at a rate dependent on the intensity of the background field. In fact, the intensity of the background field enters into the coupling constant of the strong field quantum electrodynamic Lagrangian, influencing all particle processes. A number of new phenomena occur. Particles gain an intensity-dependent rest mass shift that accounts for their presence in the dispersive vacuum. Multi-photon events involving more than one external field photon occur at each vertex. Higher order processes which exchange a virtual strong field particle resonate via the lifetimes of the unstable strong field states. Two main arenas of strong field physics are reviewed; those occurring in relativistic electron interactions with intense laser beams, and those occurring in the beam-beam physics at the interaction point of colliders. This review outlines the theory, describes its significant novel phenomenology and details the experimental schema required to detect strong field effects and the
Computational strong-field quantum dynamics. Intense light-matter interactions
Energy Technology Data Exchange (ETDEWEB)
Bauer, Dieter (ed.) [Rostock Univ. (Germany). Inst. fuer Physik
2017-09-01
This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time dependent Schroedinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.
Storti, Mario A.; Nigro, Norberto M.; Paz, Rodrigo R.; Dalcín, Lisandro D.
2009-03-01
In this paper some results on the convergence of the Gauss-Seidel iteration when solving fluid/structure interaction problems with strong coupling via fixed point iteration are presented. The flow-induced vibration of a flat plate aligned with the flow direction at supersonic Mach number is studied. The precision of different predictor schemes and the influence of the partitioned strong coupling on stability is discussed.
Computational strong-field quantum dynamics. Intense light-matter interactions
International Nuclear Information System (INIS)
Bauer, Dieter
2017-01-01
This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time dependent Schroedinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.
Computational strong-field quantum dynamics intense light-matter interactions
2017-01-01
This graduate textbook introduces the computational techniques to study ultra-fast quantum dynamics of matter exposed to strong laser fields. Coverage includes methods to propagate wavefunctions according to the time-dependent Schrödinger, Klein-Gordon or Dirac equation, the calculation of typical observables, time-dependent density functional theory, multi-configurational time-dependent Hartree-Fock, time-dependent configuration interaction singles, the strong-field approximation, and the microscopic particle-in-cell approach.
International Nuclear Information System (INIS)
Drechsler, W.
1977-01-01
A Lagrangian formalism invariant under the gauge group U 1 xUSpsub(2.2) is set up in terms of spinor fields defined on a fiber bundle with Cartan connexion. The fiber of the Cartan bundle over space-time associated with strong interactions is characterized by an elementary length parameter R related to the range of the strong forces, and the structural group USpsub(2.2) of the bundle (being the covering group of the SOsub(4.1) de Sitter group) implies a gauge description of strong interactions based on the noncompact gauge group USpsub(2.2). The U 1 factor in the total gauge group corresponds to the usual gauge formulation for the electromagnetic interactions. The positivity of the energy associated with stable extended one-particle states in this dualistic description of charged hadronic matter immersed in the fiber geometry (this dualism is called strong fiber dynamics (SFD)) requires hadrons to be assigned to representations of the compact subgroup SU 2 xSU 2 of the strong-interaction gauge group USpsub(2.2). A brief discussion of the point-particle limit R→O is given by linking the presented SFD formalism for extended hadrons to an idealized description in terms of operators in a local quantum field theory
International Nuclear Information System (INIS)
Shukla, Nitin; Shukla, P.K.
2011-01-01
The dispersion relation for the dust acoustic wave (DAW) in an unmagnetized dusty plasma cylindrical waveguide is derived, accounting for strong electrostatic interactions between charged dust grains. It is found that the boundary effect limits the radial extent of the DAW. The present result should be helpful for understanding the frequency spectrum of the DAW in a dusty plasma waveguide with strongly coupled charged dust grains. - Highlights: → We study the dust acoustic wave (DAW) in a bounded plasma. → We account for interactions between dust grains. → The boundary effect limits the radial extent of the DAW.
Proceedings of Summer Institute of Particle Physics, July 27-August 7, 1981: the strong interactions
Energy Technology Data Exchange (ETDEWEB)
Mosher, A. (ed.)
1982-01-01
The ninth SLAC Summer Institute on Particle Physics was held in the period July 27 to August 7, 1981. The central topic was the strong interactions with the first seven days spent in a pedagogic mode and the last three in a topical conference. In addition to the morning lectures on experimental and theoretical aspects of the strong interactions, three were lectures on machine physics; this year it was electron-positron colliding beam machines, both storage rings and linear colliders. Twenty-three individual items from the meeting were prepared separately for the data base. (GHT)
Marsh, Lorraine
2015-01-01
Many systems in biology rely on binding of ligands to target proteins in a single high-affinity conformation with a favorable ΔG. Alternatively, interactions of ligands with protein regions that allow diffuse binding, distributed over multiple sites and conformations, can exhibit favorable ΔG because of their higher entropy. Diffuse binding may be biologically important for multidrug transporters and carrier proteins. A fine-grained computational method for numerical integration of total binding ΔG arising from diffuse regional interaction of a ligand in multiple conformations using a Markov Chain Monte Carlo (MCMC) approach is presented. This method yields a metric that quantifies the influence on overall ligand affinity of ligand binding to multiple, distinct sites within a protein binding region. This metric is essentially a measure of dispersion in equilibrium ligand binding and depends on both the number of potential sites of interaction and the distribution of their individual predicted affinities. Analysis of test cases indicates that, for some ligand/protein pairs involving transporters and carrier proteins, diffuse binding contributes greatly to total affinity, whereas in other cases the influence is modest. This approach may be useful for studying situations where "nonspecific" interactions contribute to biological function.
Quasi-particles and effective mean field in strongly interacting matter
International Nuclear Information System (INIS)
Levai, P.; Ko, C.M.
2010-01-01
We introduce a quasi-particle model of strongly interacting quark-gluon matter and explore the possible connection to an effective field theoretical description consisting of a scalar σ field by introducing a dynamically generated mass, M(σ), and a self-consistently determined interaction term, B(σ). We display a possible connection between the two types of effective description, using the Friedberg-Lee model.
Constraining strong baryon-dark-matter interactions with primordial nucleosynthesis and cosmic rays
International Nuclear Information System (INIS)
Cyburt, Richard H.; Fields, Brian D.; Pavlidou, Vasiliki; Wandelt, Benjamin
2002-01-01
Self-interacting dark matter (SIDM) was introduced by Spergel and Steinhardt to address possible discrepancies between collisionless dark matter simulations and observations on scales of less than 1 Mpc. We examine the case in which dark matter particles not only have strong self-interactions but also have strong interactions with baryons. The presence of such interactions will have direct implications for nuclear and particle astrophysics. Among these are a change in the predicted abundances from big bang nucleosynthesis (BBN) and the flux of γ rays produced by the decay of neutral pions which originate in collisions between dark matter and galactic cosmic rays (CR). From these effects we constrain the strength of the baryon-dark-matter interactions through the ratio of baryon-dark-matter interaction cross section to dark matter mass, s. We find that BBN places a weak upper limit on this ratio (less-or-similar sign)10 8 cm 2 g -1 . CR-SIDM interactions, however, limit the possible DM-baryon cross section to (less-or-similar sign)5x10 -3 cm 2 g -1 ; this rules out an energy-independent interaction, but not one which falls with center-of-mass velocity s∝1/v or steeper
Yu, Hyun Young; Ziegelhoffer, Thomas; Osipiuk, Jerzy; Ciesielski, Szymon J; Baranowski, Maciej; Zhou, Min; Joachimiak, Andrzej; Craig, Elizabeth A
2015-04-10
Unlike other Hsp70 molecular chaperones, those of the eukaryotic cytosol have four residues, EEVD, at their C-termini. EEVD(Hsp70) binds adaptor proteins of the Hsp90 chaperone system and mitochondrial membrane preprotein receptors, thereby facilitating processing of Hsp70-bound clients through protein folding and translocation pathways. Among J-protein co-chaperones functioning in these pathways, Sis1 is unique, as it also binds the EEVD(Hsp70) motif. However, little is known about the role of the Sis1:EEVD(Hsp70) interaction. We found that deletion of EEVD(Hsp70) abolished the ability of Sis1, but not the ubiquitous J-protein Ydj1, to partner with Hsp70 in in vitro protein refolding. Sis1 co-chaperone activity with Hsp70∆EEVD was restored upon substitution of a glutamic acid of the J-domain. Structural analysis revealed that this key glutamic acid, which is not present in Ydj1, forms a salt bridge with an arginine of the immediately adjacent glycine-rich region. Thus, restoration of Sis1 in vitro activity suggests that intramolecular interactions between the J-domain and glycine-rich region control co-chaperone activity, which is optimal only when Sis1 interacts with the EEVD(Hsp70) motif. However, we found that disruption of the Sis1:EEVD(Hsp70) interaction enhances the ability of Sis1 to substitute for Ydj1 in vivo. Our results are consistent with the idea that interaction of Sis1 with EEVD(Hsp70) minimizes transfer of Sis1-bound clients to Hsp70s that are primed for client transfer to folding and translocation pathways by their preassociation with EEVD binding adaptor proteins. These interactions may be one means by which cells triage Ydj1- and Sis1-bound clients to productive and quality control pathways, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.
Chandrasekhar, Sosale; Naik, Tangali R Ravikumar; Nayak, Susanta K; Row, Tayur N Guru
2010-06-15
The titled complex, obtained by co-crystallization (EtOH/25 degrees C), is apparently the only known complex of the free bases. Its crystal structure, as determined by X-ray diffraction at both 90 K and 313 K, showed that one A-T pair involves a Hoogsteen interaction, and the other a Watson-Crick interaction but only with respect to the adenine unit. The absence of a clear-cut Watson-Crick base pair raises intriguing questions about the basis of the DNA double helix. Copyright 2010 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Bouzon Capelo, Silvia; Baranowska-Laczkowska, Angelika; Fernandez, Berta
2011-01-01
Graphical abstract: CO-Ne IPES. Highlights: → From the LPol, MLPol, and aug-pc-2 bases we obtained new bases for the evaluation of CO-Ne interaction energies. → We checked the bases on the evaluation of the rovibrational spectrum. → The results were satisfactory, being the new bases more efficient than those previously available. - Abstract: Recently we have derived new efficient basis sets for the evaluation of interaction energies in the X-Y (X, Y = He, Ne, Ar) van der Waals complexes. Here we extend the study to the CO-Ne complex. For this, we start with a systematic basis set study, where the LPol, MLPol and Jensen's aug-pc-2 basis sets are considered as starting point (for the Ne atom LPol bases are developed). As reference we take interaction energy results obtained with Dunning's augmented correlation consistent polarized valence basis sets. In all cases we test extensions with different sets of midbond functions. With the selected bases we evaluate CCSD(T) interaction potentials, and to check the potentials further, we obtain the ro-vibrational spectrum of the complex. The results are compared to the available experimental data.
The universal sound velocity formula for the strongly interacting unitary Fermi gas
International Nuclear Information System (INIS)
Liu Ke; Chen Ji-Sheng
2011-01-01
Due to the scale invariance, the thermodynamic laws of strongly interacting limit unitary Fermi gas can be similar to those of non-interacting ideal gas. For example, the virial theorem between pressure and energy density of the ideal gas P = 2E/3V is still satisfied by the unitary Fermi gas. This paper analyses the sound velocity of unitary Fermi gases with the quasi-linear approximation. For comparison, the sound velocities for the ideal Boltzmann, Bose and Fermi gas are also given. Quite interestingly, the sound velocity formula for the ideal non-interacting gas is found to be satisfied by the unitary Fermi gas in different temperature regions. (general)
Strong FANCA/FANCG but weak FANCA/FANCC interaction in the yeast 2-hybrid system.
Reuter, T; Herterich, S; Bernhard, O; Hoehn, H; Gross, H J
2000-01-15
Three of at least 8 Fanconi anemia (FA) genes have been cloned (FANCA, FANCC, FANCG), but their functions remain unknown. Using the yeast 2-hybrid system and full-length cDNA, the authors found a strong interaction between FANCA and FANCG proteins. They also obtained evidence for a weak interaction between FANCA and FANCC. Neither FANCA nor FANCC was found to interact with itself. These results support the notion of a functional association between the FA gene products. (Blood. 2000;95:719-720)
Engineering the Dynamics of Effective Spin-Chain Models for Strongly Interacting Atomic Gases
DEFF Research Database (Denmark)
Volosniev, A. G.; Petrosyan, D.; Valiente, M.
2015-01-01
We consider a one-dimensional gas of cold atoms with strong contact interactions and construct an effective spin-chain Hamiltonian for a two-component system. The resulting Heisenberg spin model can be engineered by manipulating the shape of the external confining potential of the atomic gas. We...
Superfluid quenching of the moment of inertia in a strongly interacting Fermi gas
Riedl, S.; Sánchez Guajardo, E. R.; Kohstall, C.; Hecker Denschlag, J.; Grimm, R.
2011-03-01
We report on the observation of a quenched moment of inertia resulting from superfluidity in a strongly interacting Fermi gas. Our method is based on setting the hydrodynamic gas in slow rotation and determining its angular momentum by detecting the precession of a radial quadrupole excitation. The measurements distinguish between the superfluid and collisional origins of hydrodynamic behavior, and show the phase transition.
Interaction of a neutral composite particle with a strong Coulomb field
International Nuclear Information System (INIS)
Wong, Cheuk-Yin.
1988-01-01
The author discusses the interaction of the quasi-composite (e/sup /plus//e/sup /minus//) system with an external electromagnetic field. This problem addresses the question of the origin of strong positron lines in quasi-elastic heavy-ion reactions. 3 refs
International Nuclear Information System (INIS)
Li Bingan
1988-01-01
In this letter it is shown that even in m π ≠ 0 case the Goldberger-Treiman relation is still hold in the Skyrme model. The mean square radius of strong interaction of nucleon 2 > s 1/2 is computed in the Skyrme model
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Pankrashkin, K.
2014-01-01
Roč. 39, č. 2 (2014), s. 193-212 ISSN 0360-5302 R&D Projects: GA ČR GAP203/11/0701 Institutional support: RVO:61389005 Keywords : Eigenvalue * Schrödinger operator * singular interaction * strong coupling * 35Q40 * 35P15 * 35J10 Subject RIV: BE - Theoretical Physics Impact factor: 1.013, year: 2014
Spectral asymptotics of a strong delta ' interaction supported by a surface
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Jex, M.
2014-01-01
Roč. 378, 30-31 (2014), s. 2091-2095 ISSN 0375-9601 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : delta ' surface interaction * strong coupling expansion Subject RIV: BE - Theoretical Physics Impact factor: 1.683, year: 2014
On eigenvalue asymptotics for strong delta-interactions supported by surfaces with boundaries
Czech Academy of Sciences Publication Activity Database
Dittrich, Jaroslav; Exner, Pavel; Kuhn, C.; Pankrashkin, K.
2016-01-01
Roč. 97, 1-2 (2016), s. 1-25 ISSN 0921-7134 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : singular Schrodinger operator * delta-interaction * strong coupling * eigenvalue Subject RIV: BE - Theoretical Physics Impact factor: 0.933, year: 2016
Finster, Felix
2014-01-01
The causal action principle is analyzed for a system of relativistic fermions composed of massive Dirac particles and neutrinos. In the continuum limit, we obtain an effective interaction described by classical gravity as well as the strong and electroweak gauge fields of the standard model.
Strongly interacting fermion systems. Progress report, November 15, 1994--November 14, 1995
International Nuclear Information System (INIS)
1994-01-01
This paper is the progress report for the period November 15, 1993 to November 14, 1994 for a program which relates to studies of strongly interacting fermion systems. The author has made significant progress in three areas, which are discussed in the report. These are: (1) optical properties in the open-quotes electronic structure program,close quotes calculating optical properties of quartz and urea; (2) quasi-one-dimensional systems, discussing the tuning of the large-density-wave or Peierls distortion in transition-metal linear chain compounds and the universal subgap optical absorptance of classes of quasi-one-dimensional compounds; and (3) other strongly interaction fermion systems, emphasizing the study of the effect of many-body interactions on the low-temperature properties of metals and superconductors
Exact results relating spin-orbit interactions in two-dimensional strongly correlated systems
Kucska, Nóra; Gulácsi, Zsolt
2018-06-01
A 2D square, two-bands, strongly correlated and non-integrable system is analysed exactly in the presence of many-body spin-orbit interactions via the method of Positive Semidefinite Operators. The deduced exact ground states in the high concentration limit are strongly entangled, and given by the spin-orbit coupling are ferromagnetic and present an enhanced carrier mobility, which substantially differs for different spin projections. The described state emerges in a restricted parameter space region, which however is clearly accessible experimentally. The exact solutions are provided via the solution of a matching system of equations containing 74 coupled, non-linear and complex algebraic equations. In our knowledge, other exact results for 2D interacting systems with spin-orbit interactions are not present in the literature.
Resonance tuning due to Coulomb interaction in strong near-field coupled metamaterials
International Nuclear Information System (INIS)
Roy Chowdhury, Dibakar; Xu, Ningning; Zhang, Weili; Singh, Ranjan
2015-01-01
Coulomb's law is one of the most fundamental laws of physics that describes the electrostatic interaction between two like or unlike point charges. Here, we experimentally observe a strong effect of Coulomb interaction in tightly coupled terahertz metamaterials where the split-ring resonator dimers in a unit cell are coupled through their near fields across the capacitive split gaps. Using a simple analytical model, we evaluated the Coulomb parameter that switched its sign from negative to positive values indicating the transition in the nature of Coulomb force from being repulsive to attractive depending upon the near field coupling between the split ring resonators. Apart from showing interesting effects in the strong coupling regime between meta-atoms, Coulomb interaction also allows an additional degree of freedom to achieve frequency tunable dynamic metamaterials
The strong interaction in e{sup +}e{sup -} annihilation and deep inelastic scattering
Energy Technology Data Exchange (ETDEWEB)
Samuelsson, J
1996-01-01
Various aspects of strong interactions are considered. Correlation effects in the hadronization process in a string model are studied. A discrete approximation scheme to the perturbative QCD cascade in e{sup +}e{sup -} annihilation is formulated. The model, Discrete QCD, predicts a rather low phase space density of `effective gluons`. This is related to the properties of the running coupling constant. It provides us with a simple tool for studies of the strong interaction. It is shown that it reproduces well-known properties of parton cascades. A new formalism for the Deep Inelastic Scattering (DIS) process is developed. The model which is called the Linked Dipole Chain Model provides an interpolation between regions of high Q{sup 2} (DGLAP) and low x-moderate Q{sup 2} (BFKL). It gives a unified treatment of the different interaction channels an a DIS process. 17 figs.
The strong interaction in e+e- annihilation and deep inelastic scattering
International Nuclear Information System (INIS)
Samuelsson, J.
1996-01-01
Various aspects of strong interactions are considered. Correlation effects in the hadronization process in a string model are studied. A discrete approximation scheme to the perturbative QCD cascade in e + e - annihilation is formulated. The model, Discrete QCD, predicts a rather low phase space density of 'effective gluons'. This is related to the properties of the running coupling constant. It provides us with a simple tool for studies of the strong interaction. It is shown that it reproduces well-known properties of parton cascades. A new formalism for the Deep Inelastic Scattering (DIS) process is developed. The model which is called the Linked Dipole Chain Model provides an interpolation between regions of high Q 2 (DGLAP) and low x-moderate Q 2 (BFKL). It gives a unified treatment of the different interaction channels an a DIS process. 17 figs
DEFF Research Database (Denmark)
Petrosyan, David; Molmer, Klaus
2013-01-01
We study two-photon excitation of Rydberg states of atoms under stimulated adiabatic passage with delayed laser pulses. We find that the combination of strong interaction between the atoms in Rydberg state and the spontaneous decay of the intermediate exited atomic state leads to the Rydberg exci...... for deterministic creation and, possibly, extraction of Rydberg atoms or ions one at a time. The sympathetic monitoring via decay of ancilla particles may find wider applications for state preparation and probing of interactions in dissipative many-body systems.......We study two-photon excitation of Rydberg states of atoms under stimulated adiabatic passage with delayed laser pulses. We find that the combination of strong interaction between the atoms in Rydberg state and the spontaneous decay of the intermediate exited atomic state leads to the Rydberg...
Systematic study on intermolecular valence-band dispersion in molecular crystalline films
International Nuclear Information System (INIS)
Yamane, Hiroyuki; Kosugi, Nobuhiro
2015-01-01
Highlights: • Intermolecular valence-band dispersion of crystalline films of phthalocyanines. • Intermolecular transfer integral versus lattice constant. • Site-specific intermolecular interaction and resultant valence-band dispersion. • Band narrowing effect induced by elevated temperature. - Abstract: Functionalities of organic semiconductors are governed not only by individual properties of constituent molecules but also by solid-state electronic states near the Fermi level such as frontier molecular orbitals, depending on weak intermolecular interactions in various conformations. The individual molecular property has been widely investigated in detail; on the other hand, the weak intermolecular interaction is difficult to investigate precisely due to the presence of the structural and thermal energy broadenings in organic solids. Here we show quite small but essential intermolecular valence band dispersions and their temperature dependence of sub-0.1-eV scale in crystalline films of metal phthalocyanines (H_2Pc, ZnPc, CoPc, MnPc, and F_1_6ZnPc) by using angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. The observed bands show intermolecular and site dependent dispersion widths, phases, and periodicities, for different chemical substitution of terminal groups and central metals in the phthalocyanine molecule. The precise and systematic band-dispersion measurement would be a credible approach toward the comprehensive understanding of intermolecular interactions and resultant charge transport properties as well as their tuning by substituents in organic molecular systems.
Elaboration of the recently proposed test of Pauli's principle under strong interactions
International Nuclear Information System (INIS)
Ktorides, C.N.; Myung, H.C.; Santilli, R.M.
1980-01-01
The primary objective of this paper is to stimulate the experimental verification of the validity or invalidity of Pauli's principle under strong interactions. We first outline the most relevant steps in the evolution of the notion of particle. The spin as well as other intrinsic characteristics of extended, massive, particles under electromagnetic interactions at large distances might be subjected to a mutation under additional strong interactions at distances smaller than their charge radius. These dynamical effects can apparently be conjectured to account for the nonpointlike nature of the particles, their necessary state of penetration to activate the strong interactions, and the consequential emergence of broader forces which imply the breaking of the SU(2)-spin symmetry. We study a characterization of the mutated value of the spin via the transition from the associative enveloping algebra of SU(2) to a nonassociative Lie-admissible form. The departure from the original associative product then becomes directly representative of the breaking of the SU(2)-spin symmetry, the presence of forces more general than those derivable from a potential, and the mutated value of the spin. In turn, such a departure of the spin from conventional quantum-mechanical values implies the inapplicability of Pauli's exclusion principle under strong interactions, because, according to this hypothesis, particles that are fermions under long-range electromagnetic interactions are no longer fermions under these broader, short-range, forces. In nuclear physics possible deviations from Pauli's exclusion principle can at most be very small. These experimental data establish that, for the nuclei considered, nucleons are in a partial state of penetration of their charge volumes although of small statistical character
Lavrik, N. L.; Mulloev, N. U.
2018-02-01
The methods of absorption and fluorescence were used to study the efficiency of the interaction between salicylic acid derivatives SAD (neutral SA form and SA monoanion) and Cd2 + ions (in CdBr2 salt) within the range pH = 1.5 ÷ 8. The efficiency was determined from the change in both the absorption band contour and the fluorescence intensity of various SAD forms. It has been established that depending on the SAD form, the addition of CdBr2 to a starting solution leads to the formation of additional absorption for both the shorter wave lengths in the absorption spectrum of the neutral form (at pH 4). In the fluorescence spectra, the intensity was observed to increase for the neutral SAD form (at pH 4) after addition of CdBr2. The spectral changes were interpreted in the framework of common notions about the effect of three physicochemical factors that determine the interaction between the SAD and the Cd2 + ion and affect the parameters of absorption and fluorescence spectra. These factors are: (1) the decrease in pH after addition of CdBr2 to the SAD solution, (2) the decrease in the efficiency of the H-bonding of SAD molecules to the water ones, and (3) the existence of electrostatic ion-ion interaction between the HSal- monoanion and the Cd2 + ion. The bimolecular fluorescence quenching constants Kq of HSal- monoanion fluorescence quenching by the Cd2 + ion appeared to be substantially less than those of the quenching which would follow either the dynamic (diffusion) or the concentration (static) mechanisms.
Soave, Raffaella; Colombo, Pietro
2013-12-15
The title 1,4-naphthoquinone, 2-dichloromethyl-3-methyl-1,4-dihydronaphthalene-1,4-dione, C12H8Cl2O2, is a chlorinated derivative of vitamin K3, which is a synthetic compound also known as menadione. Molecules of (I) are planar and lie on a crystallographic mirror plane (Z' = 0.5) in the space group Pnma. They are connected to each other by C-H···O hydrogen bonds, forming two-dimensional layers parallel to the ac plane. In addition, Cl···Cl and π-π interactions link adjacent molecules in different layers, thus forming zigzag ribbons along the b axis, such that a three-dimensional architecture is generated.
Zhang, Yu-Nan; Yin, He-Mei; Zhang, Yu; Zhang, Da-Jun; Su, Xin; Kuang, Hai-Xue
2017-02-01
With an aim to explore the interactions of Osbnd H⋯N between hydroxyl moiety of the flavonoids and the pyridyl ring of N-containing aromatic amines, three flavonols with varying B-ring-hydroxyl groups (kaempferol, quercetin, and myricetin) were selected to combine with 4,4‧-bipyridine. As a result, three new cocrystals of flavonols were obtained with a solution evaporation approach. These three cocrystals were characterized by single crystal X-ray diffraction, XPRD, IR and NMR methods. The resulting cocrystals were kaempferol: 4,4‧-bipyridine (2:1) (KAE·BPY·2H2O), quercetin: 4,4‧-bipyridine (1:1.5) (QUE·BPY), and myricetin: 4,4‧-bipyridine (1:2) (MYR·BPY·H2O). Structural analyses show that an array of hydrogen bonds and π-π stacking interactions interconnect the molecules to form a two-dimensional (2D) supramolecular layer in KAE·BPY·2H2O, QUE·BPY, and MYR·BPY·H2O. In the three cocrystals, they present as three different synthons-ⅠR88(58), Ⅳ R44(42) and, Ⅶ R66(29) with 4,4‧-bipyridine, respectively-which may yield a strategy for constructing the supramolecule. Cocrystals of flavonols combined with N-containing aromatic amines, 7-OH, B-ring-hydroxyl number and/or the location of the flavonols to play a significant part in extending the dimensionality of the cocrystals. The resulting motif formation and crystal packing in these flavonols cocrystals has combined with N-containing aromatic amines. Additionally, the antibacterial properties of the three cocrystals against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) have been investigated.
Li, Qiaoyun; Wan, Xiaocao; Liu, Chao; Fang, Liang
2018-07-01
The aim of this study was to prepare a drug-in-adhesive patch of nicotine (NIC) and use ion-pair strategy to regulate drug delivery rate. Moreover, the mechanism of how ion-pair strategy regulated drug release was elucidated at molecular level. Formulation factors including pressure sensitive adhesives (PSAs), drug loading and counter ions (C 4 , C 6 , C 8 , C 10 , and C 12 ) were screened. In vitro release experiment and in vitro transdermal experiment were conducted to determine the rate-limiting step in drug delivery process. FT-IR and molecular modeling were used to characterize the interaction between drug and PSA. Thermal analysis and rheology study were conducted to investigate the mobility variation of PSA. The optimized patch prepared with NIC-C 8 had the transdermal profile fairly close to that of the commercial product (p > 0.05). The release rate constants (k) of NIC, NIC-C 4 and NIC-C 10 were 21.1, 14.4 and 32.4, respectively. Different release rates of NIC ion-pair complexes were attributed to the dual effect of ion-pair strategy on drug release. On one hand, ion-pair strategy enhanced the interaction between drug and PSA, which inhibited drug release. On the other hand, using ion-pair strategy improved the mobility of PSA, which facilitated drug release. Drug release behavior was determined by combined effect of two aspects above. These conclusions provided a new idea for us to regulate drug release behavior from patch. Copyright © 2018 Elsevier B.V. All rights reserved.
Heavy quark mass effects and improved tests of the flavor independence of strong interactions
Energy Technology Data Exchange (ETDEWEB)
Burrows, P.N. [Univ. of Oxford (United Kingdom); SLD Collaboration
1998-08-01
A review is given of latest results on tests of the flavor independence of strong interactions. Heavy quark mass effects are evident in the data and are now taken into account at next-to-leading order in QCD perturbation theory. The strong-coupling ratios {alpha}{sub s}{sup b}/{alpha}{sub s}{sup uds} and {alpha}{sub s}{sup c}/{alpha}{sub s}{sup uds} are found to be consistent with unity. Determinations of the b-quark mass m{sub b} (M{sub Z}) are discussed.
International Nuclear Information System (INIS)
Sivan, N.; Levit, S.
1992-01-01
We present a semiclassical theory of charged interacting anyons in a strong magnetic field. We derive the appropriate generalization of the WKB quantization conditions and determine the corresponding wave functions for non separable integrable anyonic systems. This theory is applies to a system of two interacting anyons, two interacting anyons in the presence of an impurity and three interacting anyons. We calculate the dependence of the semiclassical energy levels on the statistical parameter and find regions in which dependence follows very different patterns. The semiclassical treatment allows to find the correlation between these patterns and the change in the character of the classical motion of the system. We also test the accuracy of the mean field approximation for low and high energy states of the three anyons. (author)
Hołyst, Robert; Litniewski, Marek; Jakubczyk, Daniel
2017-09-13
Transport of heat to the surface of a liquid is a limiting step in the evaporation of liquids into an inert gas. Molecular dynamics (MD) simulations of a two component Lennard-Jones (LJ) fluid revealed two modes of energy transport from a vapour to an interface of an evaporating droplet of liquid. Heat is transported according to the equation of temperature diffusion, far from the droplet of radius R. The heat flux, in this region, is proportional to temperature gradient and heat conductivity in the vapour. However at some distance from the interface, Aλ, (where λ is the mean free path in the gas), the temperature has a discontinuity and heat is transported ballistically i.e. by direct individual collisions of gas molecules with the interface. This ballistic transport reduces the heat flux (and consequently the mass flux) by the factor R/(R + Aλ) in comparison to the flux obtained from temperature diffusion. Thus it slows down the evaporation of droplets of sizes R ∼ Aλ and smaller (practically for sizes from 10 3 nm down to 1 nm). We analyzed parameter A as a function of interactions between molecules and their masses. The rescaled parameter, A(k B T b /ε 11 ) 1/2 , is a linear function of the ratio of the molecular mass of the liquid molecules to the molecular mass of the gas molecules, m 1 /m 2 (for a series of chemically similar compounds). Here ε 11 is the interaction parameter between molecules in the liquid (proportional to the enthalpy of evaporation) and T b is the temperature of the gas in the bulk. We tested the predictions of MD simulations in experiments performed on droplets of ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol. They were suspended in an electrodynamic trap and evaporated into dry nitrogen gas. A changes from ∼1 (for ethylene glycol) to approximately 10 (for tetraethylene glycol) and has the same dependence on molecular parameters as obtained for the LJ fluid in MD simulations. The value of x = A
Strong constraints on self-interacting dark matter with light mediators
International Nuclear Information System (INIS)
Bringmann, Torsten; Walia, Parampreet
2017-04-01
Coupling dark matter to light new particles is an attractive way to combine thermal production with strong velocity-dependent self-interactions. Here we point out that in such models the dark matter annihilation rate is generically enhanced by the Sommerfeld effect, and we derive the resulting constraints from the Cosmic Microwave Background and other indirect detection probes. For the frequently studied case of s-wave annihilation these constraints exclude the entire parameter space where the self-interactions are large enough to address the small-scale problems of structure formation.
Nonlinear interaction of strong microwave beam with the ionosphere MINIX rocket experiment
Energy Technology Data Exchange (ETDEWEB)
Kaya, N.; Matsumoto, H.; Miyatake, S.; Kimura, I.; Nagatomo, M.; Obayashi, T.
1986-01-01
A rocket-borne experiment called MINIX was carried out to investigate the nonlinear interaction of a strong microwave energy beam with the ionosphere. The MINIX stands for Microwave-Ionosphere Nonlinear Interaction Experiment and was carried out on August 29, 1983. The objectives of the MINIX is to study possible impacts of the SPS microwave energy beam on the ionosphere such as the Ohmic heating and plasma wave excitation. The experiment showed that the microwave with f = 2.45 GHz nonlinearly excites various electrostatic plasma waves, though no Ohmic heating effects were detected. 4 figures.
Nonlinear interaction of strong microwave beam with the ionosphere MINIX rocket experiment
Kaya, N.; Matsumoto, H.; Miyatake, S.; Kimura, I.; Nagatomo, M.
A rocket-borne experiment called 'MINIX' was carried out to investigate the nonlinear interaction of a strong microwave energy beam with the ionosphere. The MINIX stands for Microwave-Ionosphere Nonlinear Interaction eXperiment and was carried out on August 29, 1983. The objective of the MINIX is to study possible impacts of the SPS microwave energy beam on the ionosphere, such as the ohmic heating and plasma wave excitation. The experiment showed that the microwave with f = 2.45 GHz nonlinearly excites various electrostatic plasma waves, though no ohmic heating effects were detected.
Nonlinear interaction of strong microwave beam with the ionosphere MINIX rocket experiment
International Nuclear Information System (INIS)
Kaya, N.; Matsumoto, H.; Miyatake, S.; Kimura, I.; Nagatomo, M.; Obayashi, T.
1986-01-01
A rocket-borne experiment called MINIX was carried out to investigate the nonlinear interaction of a strong microwave energy beam with the ionosphere. The MINIX stands for Microwave-Ionosphere Nonlinear Interaction Experiment and was carried out on August 29, 1983. The objectives of the MINIX is to study possible impacts of the SPS microwave energy beam on the ionosphere such as the Ohmic heating and plasma wave excitation. The experiment showed that the microwave with f = 2.45 GHz nonlinearly excites various electrostatic plasma waves, though no Ohmic heating effects were detected. 4 figures
Metastability and coherence of repulsive polarons in a strongly interacting Fermi mixture
DEFF Research Database (Denmark)
Kohstall, Cristoph; Zaccanti, Mattheo; Jag, Matthias
2012-01-01
show that a well-defined quasiparticle exists for strongly repulsive interactions. We measure the energy and the lifetime of this ‘repulsive polaron’9, 12, 13, and probe its coherence properties by measuring the quasiparticle residue. The results are well described by a theoretical approach that takes...... into account the finite effective range of the interaction in our system. We find that when the effective range is of the order of the interparticle spacing, there is a substantial increase in the lifetime of the quasiparticles. The existence of such a long-lived, metastable many-body state offers intriguing...
Strong constraints on self-interacting dark matter with light mediators
Energy Technology Data Exchange (ETDEWEB)
Bringmann, Torsten; Walia, Parampreet [Oslo Univ. (Norway). Dept. of Physics; Kahlhoefer, Felix; Schmidt-Hoberg, Kai [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)
2017-04-15
Coupling dark matter to light new particles is an attractive way to combine thermal production with strong velocity-dependent self-interactions. Here we point out that in such models the dark matter annihilation rate is generically enhanced by the Sommerfeld effect, and we derive the resulting constraints from the Cosmic Microwave Background and other indirect detection probes. For the frequently studied case of s-wave annihilation these constraints exclude the entire parameter space where the self-interactions are large enough to address the small-scale problems of structure formation.
Universal Behavior of Pair Correlations in a Strongly Interacting Fermi Gas
International Nuclear Information System (INIS)
Kuhnle, E. D.; Hu, H.; Liu, X.-J.; Dyke, P.; Mark, M.; Drummond, P. D.; Hannaford, P.; Vale, C. J.
2010-01-01
We show that short-range pair correlations in a strongly interacting Fermi gas follow a simple universal law described by Tan's relations. This is achieved through measurements of the static structure factor which displays a universal scaling proportional to the ratio of Tan's contact to the momentum C/q. Bragg spectroscopy of ultracold 6 Li atoms from a periodic optical potential is used to measure the structure factor for a wide range of momenta and interaction strengths, providing broad confirmation of this universal law. We calibrate our Bragg spectra using the f-sum rule, which is found to improve the accuracy of the structure factor measurement.
International Nuclear Information System (INIS)
Arnold, R.C.
1975-12-01
A systematic calculus of long-range Regge cut effects in multiparticle production is constructed in the form of an infrared-divergent stochastic field theory. Total cross sections and two-body overlap integrals in such a theory may depend very sensitively upon internal quantum-numbers of incident particles, resulting in a strong symmetry breaking at ultra-high energies. Such symmetry violations will influence low energy processes through dispersion relations, and a bootstrap of weak interactions becomes possible. A rough analytic estimate of the scale of thresholds for such effects yields a BCS-type gap equation, which expresses the scale of weak and electromagnetic couplings in terms of purely strong-interaction parameters
On the Frequency Distribution of Neutral Particles from Low-Energy Strong Interactions
Directory of Open Access Journals (Sweden)
Federico Colecchia
2017-01-01
Full Text Available The rejection of the contamination, or background, from low-energy strong interactions at hadron collider experiments is a topic that has received significant attention in the field of particle physics. This article builds on a particle-level view of collision events, in line with recently proposed subtraction methods. While conventional techniques in the field usually concentrate on probability distributions, our study is, to our knowledge, the first attempt at estimating the frequency distribution of background particles across the kinematic space inside individual collision events. In fact, while the probability distribution can generally be estimated given a model of low-energy strong interactions, the corresponding frequency distribution inside a single event typically deviates from the average and cannot be predicted a priori. We present preliminary results in this direction and establish a connection between our technique and the particle weighting methods that have been the subject of recent investigation at the Large Hadron Collider.
Gauge unification of basic forces, particularly of gravitation with strong interactions
International Nuclear Information System (INIS)
Salam, A.
1977-01-01
An attempt is made to present a case for the use of both the Einstein--Weyl spin-two and the Yang--Mills spin-one gauge structures for describing strong interactions. By emphasizing both spin-one and -two aspects of this force, it is hoped that a unification of this force, on the one hand, with gravity theory and, on the other, with the electromagnetic and weak interactions can be achieved. A Puppi type of tetrahedral interralation of fundamental forces, with the strong force playing a pivotal role due to its mediation through both spin-one and -two quanta, is proposed. It is claimed that the gauge invariance of gravity theory permits the use of ambuguity-free nonpolynomial techniques and thereby the securing of relistic regularization in gravity-modified field theories with the Newtonian constant G/sub N/ providing a relistic cutoff. 37 references
Les Houches Summer School : Strongly Interacting Quantum Systems out of Equilibrium
Millis, Andrew J; Parcollet, Olivier; Saleur, Hubert; Cugliandolo, Leticia F
2016-01-01
Over the last decade new experimental tools and theoretical concepts are providing new insights into collective nonequilibrium behavior of quantum systems. The exquisite control provided by laser trapping and cooling techniques allows us to observe the behavior of condensed bose and degenerate Fermi gases under nonequilibrium drive or after quenches' in which a Hamiltonian parameter is suddenly or slowly changed. On the solid state front, high intensity short-time pulses and fast (femtosecond) probes allow solids to be put into highly excited states and probed before relaxation and dissipation occur. Experimental developments are matched by progress in theoretical techniques ranging from exact solutions of strongly interacting nonequilibrium models to new approaches to nonequilibrium numerics. The summer school Strongly interacting quantum systems out of equilibrium' held at the Les Houches School of Physics as its XCIX session was designed to summarize this progress, lay out the open questions and define dir...
Anisotropy of the magnetoviscous effect in a cobalt ferrofluid with strong interparticle interaction
Energy Technology Data Exchange (ETDEWEB)
Linke, J.M., E-mail: julia.linke@tu-dresden.de; Odenbach, S.
2015-12-15
The anisotropy of the magnetoviscous effect (MVE) of a cobalt ferrofluid has been studied in a slit die viscometer for three orientations of the applied magnetic field: in the direction of the fluid flow (Δη{sub 1}), the velocity gradient (Δη{sub 2}), and the vorticity (Δη{sub 3}). The majority of the cobalt particles in the ferrofluid exhibit a strong dipole–dipole interaction, which corresponds to a weighted interaction parameter of λ{sub w}≈10.6. Thus the particles form extended microstructures inside the fluid which lead to enhanced MVE ratios Δη{sub 2}/Δη{sub 1}>3 and Δη{sub 3}/Δη{sub 1}>0.3 even for strong shearing and weak magnetic fields compared to fluids which contain non-interacting spherical particles with Δη{sub 2}/Δη{sub 1}≈1 and Δη{sub 3}/Δη{sub 1}=0. Furthermore, a non-monotonic increase has been observed in the shear thinning behavior of Δη{sub 2} for weak magnetic fields <10 kA/m, which cannot be explained solely by the magnetization of individual particles and the formation and disintegration of linear particle chains but indicates the presence of heterophase structures. - Highlights: • The magnetoviscous effect in a ferrofluid with strong interaction is anisotropic. • The strongest effects are found in a magnetic field parallel to the shear gradient. • In strong magnetic fields the microstructure of the fluid is stable against shearing. • In weak fields the fluid behavior indicates the presence of heterophase structures.
Quasi-particle description of strongly interacting matter: Towards a foundation
International Nuclear Information System (INIS)
Bluhm, M.; Kaempfer, B.; Schulze, R.; Seipt, D.
2007-01-01
We confront our quasi-particle model for the equation of state of strongly interacting matter with recent first-principle QCD calculations. In particular, we test its applicability at finite baryon densities by comparing with Taylor expansion coefficients of the pressure for two quark flavours. We outline a chain of approximations starting from the Φ-functional approach to QCD which motivates the quasi-particle picture. (orig.)
Limitations due to strong head-on beam-beam interactions (MD 1434)
Buffat, Xavier; Iadarola, Giovanni; Papadopoulou, Parthena Stefania; Papaphilippou, Yannis; Pellegrini, Dario; Pojer, Mirko; Crockford, Guy; Salvachua Ferrando, Belen Maria; Trad, Georges; Barranco Garcia, Javier; Pieloni, Tatiana; Tambasco, Claudia; CERN. Geneva. ATS Department
2017-01-01
The results of an experiment aiming at probing the limitations due to strong head on beam-beam interactions are reported. It is shown that the loss rates significantly increase when moving the working point up and down the diagonal, possibly due to effects of the 10th and/or 14th order resonances. Those limitations are tighter for bunches with larger beam-beam parameters, a maximum total beam-beam tune shift just below 0.02 could be reached.
Fractional energy states of strongly-interacting bosons in one dimension
DEFF Research Database (Denmark)
Zinner, Nikolaj Thomas; G. Volosniev, A.; V. Fedorov, D.
2014-01-01
We study two-component bosonic systems with strong inter-species and vanishing intra-species interactions. A new class of exact eigenstates is found with energies that are {\\it not} sums of the single-particle energies with wave functions that have the characteristic feature that they vanish over...... than three particles. The states can be probed using the same techniques that have recently been used for fermionic few-body systems in quasi-1D.......We study two-component bosonic systems with strong inter-species and vanishing intra-species interactions. A new class of exact eigenstates is found with energies that are {\\it not} sums of the single-particle energies with wave functions that have the characteristic feature that they vanish over...... extended regions of coordinate space. This is demonstrated in an analytically solvable model for three equal mass particles, two of which are identical bosons, which is exact in the strongly-interacting limit. We numerically verify our results by presenting the first application of the stochastic...
Strong excitonic interactions in the oxygen K-edge of perovskite oxides.
Tomita, Kota; Miyata, Tomohiro; Olovsson, Weine; Mizoguchi, Teruyasu
2017-07-01
Excitonic interactions of the oxygen K-edge electron energy-loss near-edge structure (ELNES) of perovskite oxides, CaTiO 3 , SrTiO 3 , and BaTiO 3 , together with reference oxides, MgO, CaO, SrO, BaO, and TiO 2 , were investigated using a first-principles Bethe-Salpeter equation calculation. Although the transition energy of oxygen K-edge is high, strong excitonic interactions were present in the oxygen K-edge ELNES of the perovskite oxides, whereas the excitonic interactions were negligible in the oxygen K-edge ELNES of the reference compounds. Detailed investigation of the electronic structure suggests that the strong excitonic interaction in the oxygen K-edge ELNES of the perovskite oxides is caused by the directionally confined, low-dimensional electronic structure at the Ti-O-Ti bonds. Copyright © 2016 Elsevier B.V. All rights reserved.
arXiv Recent results and future of the NA61/SHINE strong interactions program
Lysakowski, Bartosz
2018-01-01
NA61/SHINE is a fixed target experiment at the CERN Super-Proton- Synchrotron. The main goals of the experiment are to discover the critical point of strongly interacting matter and study the properties of the onset of deconfnement. In order to reach these goals the collaboration studies hadron production properties in nucleus-nucleus, proton-proton and proton-nucleus interactions. In this talk, recent results on particle production in p+p interactions, as well as Be+Be and Ar+Sc collisions in the SPS energy range are reviewed. The results are compared with available world data. The future of the NA61/SHINE scientifc program is also presented.
Interacting Electrons and Holes in Quasi-2D Quantum Dots in Strong Magnetic Fields
Hawrylak, P.; Sheng, W.; Cheng, S.-J.
2004-09-01
Theory of optical properties of interacting electrons and holes in quasi-2D quantum dots in strong magnetic fields is discussed. In two dimensions and the lowest Landau level, hidden symmetries control the interaction of the interacting system with light. By confining electrons and holes into quantum dots hidden symmetries can be removed and the excitation spectrum of electrons and excitons can be observed. We discuss a theory electronic and of excitonic quantum Hall droplets at a filling factorν=2. For an excitonic quantum Hall droplet the characteristic emission spectra are predicted to be related to the total spin of electron and hole configurations. For the electronic droplet the excitation spectrum of the droplet can be mapped out by measuring the emission for increasing number of electrons.
Interacting electrons and holes in quasi-2D quantum dots in strong magnetic fields
International Nuclear Information System (INIS)
Hawrylak, P.; Sheng, W.; Cheng, S.-J.
2004-01-01
Theory of optical properties of interacting electrons and holes in quasi-2D quantum dots in strong magnetic fields is discussed. In two dimensions and the lowest Landau level, hidden symmetries control the interaction of the interacting system with light. By confining electrons and holes into quantum dots hidden symmetries can be removed and the excitation spectrum of electrons and excitons can be observed. We discuss a theory electronic and excitonic quantum Hall droplets at a filling factor υ = 2. For an excitonic quantum Hall droplet the characteristic emission spectra are predicted to be related to the total spin of electron and hole configurations. For the electronic droplet the excitation spectrum of the droplet can be mapped out by measuring the emission for increasing number of electrons. (author)
Strong late-time circumstellar interaction in the peculiar supernova iPTF14hls
Andrews, Jennifer E.; Smith, Nathan
2018-06-01
We present a moderate-resolution spectrum of the peculiar Type II supernova (SN) iPTF14hls taken on day 1153 after discovery. This spectrum reveals the clear signature of shock interaction with dense circumstellar material (CSM). We suggest that this CSM interaction may be an important clue for understanding the extremely unusual photometric and spectroscopic evolution seen over the first 600 d of iPTF14hls. The late-time spectrum shows a double-peaked intermediate-width H α line indicative of expansion speeds around 1000 km s-1, with the double-peaked shape hinting at a disc-like geometry in the CSM. If the CSM were highly asymmetric, perhaps in a disc or torus that was ejected from the star 3-6 yr prior to explosion, the CSM interaction could have been overrun and hidden below the SN ejecta photosphere from a wide range of viewing angles. In that case, CSM interaction luminosity would have been thermalized well below the photosphere, potentially sustaining the high luminosity without exhibiting the traditional observational signatures of strong CSM interaction (narrow H α emission and X-rays). Variations in density structure of the CSM could account for the multiple rebrightenings of the light curve. We propose that a canonical 1 × 1051 erg explosion energy with enveloped CSM interaction as seen in some recent SNe, rather than an entirely new explosion mechanism, may be adequate to explain the peculiar evolution of iPTF14hls.
Dovzhenko, D S; Ryabchuk, S V; Rakovich, Yu P; Nabiev, I R
2018-02-22
Resonance interaction between a molecular transition and a confined electromagnetic field can reach the coupling regime where coherent exchange of energy between light and matter becomes reversible. In this case, two new hybrid states separated in energy are formed instead of independent eigenstates, which is known as Rabi splitting. This modification of the energy spectra of the system offers new possibilities for controlled impact on various fundamental properties of coupled matter (such as the rate of chemical reactions and the conductivity of organic semiconductors). To date, the strong coupling regime has been demonstrated in many configurations under different ambient conditions. However, there is still no comprehensive approach to determining parameters for achieving the strong coupling regime for a wide range of practical applications. In this review, a detailed analysis of various systems and corresponding conditions for reaching strong coupling is carried out and their advantages and disadvantages, as well as the prospects for application, are considered. The review also summarizes recent experiments in which the strong coupling regime has led to new interesting results, such as the possibility of collective strong coupling between X-rays and matter excitation in a periodic array of Fe isotopes, which extends the applications of quantum optics; a strong amplification of the Raman scattering signal from a coupled system, which can be used in surface-enhanced and tip-enhanced Raman spectroscopy; and more efficient second-harmonic generation from the low polaritonic state, which is promising for nonlinear optics. The results reviewed demonstrate great potential for further practical applications of strong coupling in the fields of photonics (low-threshold lasers), quantum communications (switches), and biophysics (molecular fingerprinting).
Magnetized Langmuir wave packets excited by a strong beam-plasma interaction
International Nuclear Information System (INIS)
Pelletier, G.; Sol, H.; Asseo, E.
1988-01-01
The physics of beam-plasma interaction, which has been investigated for a long time mostly in relation with solar bursts, is now more widely invoked in various astrophysical contexts such as pulsars, active galactic nuclei, close binaries, cataclysmic variables, γ bursters, and so on. In these situations the interaction is more likely in the spirit of strong Langmuir turbulence rather than in the spirit of quasilinear theory. Many investigations have been done for two opposite extremes, namely, in very weak and in very strong magnetic fields. Very few properties of the strong Langmuir turbulence are known in the most usual astrophysical situation where the magnetic field plays a significant role but is not strong enough to force the electrons into one-dimensional motion. For this case, we analyze the dynamics of Langmuir wave packets and provide new results about the stability of the solitons against transverse perturbations. It turns out that both the averaged Lagrangian method and the adiabatic perturbation method derived from the inverse scattering transform give exactly the same results (which is not obvious in soliton perturbation theory). In particular, they predict the stability of the solitons as long as the electron gyrofrequency is greater than the plasma frequency (strong magnetic field) and their instability against transverse self-modulation in the opposite case (weak magnetic field); moreover, they allow one to deduce the self-similar collapsing oblate cavitons in the latter case. The laws governing the collapse of the wave packets determine the relaxation of the beam in the surrounding medium and we derive a useful formula giving the power loss of the beam. We outline the astrophysical consequences of this investigation
Directory of Open Access Journals (Sweden)
Aditi Gupta
2016-03-01
Full Text Available Epistatic interactions between residues determine a protein's adaptability and shape its evolutionary trajectory. When a protein experiences a changed environment, it is under strong selection to find a peak in the new fitness landscape. It has been shown that strong selection increases epistatic interactions as well as the ruggedness of the fitness landscape, but little is known about how the epistatic interactions change under selection in the long-term evolution of a protein. Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1 using protease sequences collected for almost a decade from both treated and untreated patients, to understand how epistasis changes and how those changes impact the long-term evolvability of a protein. We use an information-theoretic proxy for epistasis that quantifies the co-variation between sites, and show that positive information is a necessary (but not sufficient condition that detects epistasis in most cases. We analyze the "fossils" of the evolutionary trajectories of the protein contained in the sequence data, and show that epistasis continues to enrich under strong selection, but not for proteins whose environment is unchanged. The increase in epistasis compensates for the information loss due to sequence variability brought about by treatment, and facilitates adaptation in the increasingly rugged fitness landscape of treatment. While epistasis is thought to enhance evolvability via valley-crossing early-on in adaptation, it can hinder adaptation later when the landscape has turned rugged. However, we find no evidence that the HIV-1 protease has reached its potential for evolution after 9 years of adapting to a drug environment that itself is constantly changing. We suggest that the mechanism of encoding new information into pairwise interactions is central to protein evolution not just in HIV-1 protease, but for any protein adapting to a changing
Ghodrat, Malihe; Naji, Ali; Komaie-Moghaddam, Haniyeh; Podgornik, Rudolf
2015-05-07
We study the effective interaction mediated by strongly coupled Coulomb fluids between dielectric surfaces carrying quenched, random monopolar charges with equal mean and variance, both when the Coulomb fluid consists only of mobile multivalent counterions and when it consists of an asymmetric ionic mixture containing multivalent and monovalent (salt) ions in equilibrium with an aqueous bulk reservoir. We analyze the consequences that follow from the interplay between surface charge disorder, dielectric and salt image effects, and the strong electrostatic coupling that results from multivalent counterions on the distribution of these ions and the effective interaction pressure they mediate between the surfaces. In a dielectrically homogeneous system, we show that the multivalent counterions are attracted towards the surfaces with a singular, disorder-induced potential that diverges logarithmically on approach to the surfaces, creating a singular but integrable counterion density profile that exhibits an algebraic divergence at the surfaces with an exponent that depends on the surface charge (disorder) variance. This effect drives the system towards a state of lower thermal 'disorder', one that can be described by a renormalized temperature, exhibiting thus a remarkable antifragility. In the presence of an interfacial dielectric discontinuity, the singular behavior of counterion density at the surfaces is removed but multivalent counterions are still accumulated much more strongly close to randomly charged surfaces as compared with uniformly charged ones. The interaction pressure acting on the surfaces displays in general a highly non-monotonic behavior as a function of the inter-surface separation with a prominent regime of attraction at small to intermediate separations. This attraction is caused directly by the combined effects from charge disorder and strong coupling electrostatics of multivalent counterions, which dominate the surface-surface repulsion due to
International Nuclear Information System (INIS)
Lee, J. Y.; Guan, X. W.; Batchelor, M. T.; Lee, C.
2009-01-01
We investigate magnetism and quantum phase transitions in a one-dimensional system of integrable spin-1 bosons with strongly repulsive density-density interaction and antiferromagnetic spin-exchange interaction via the thermodynamic Bethe ansatz method. At zero temperature, the system exhibits three quantum phases: (i) a singlet phase of boson pairs when the external magnetic field H is less than the lower critical field H c1 ; (ii) a ferromagnetic phase of atoms in the hyperfine state |F=1, m F =1> when the external magnetic field exceeds the upper critical field H c2 ; and (iii) a mixed phase of singlet pairs and unpaired atoms in the intermediate region H c1 c2 . At finite temperatures, the spin fluctuations affect the thermodynamics of the model through coupling the spin bound states to the dressed energy for the unpaired m F =1 bosons. However, such spin dynamics is suppressed by a sufficiently strong external field at low temperatures. Thus the singlet pairs and unpaired bosons may form a two-component Luttinger liquid in the strong coupling regime.
Patel, M; Sanches, F F; Mallia, G; Harrison, N M
2014-10-21
Periodic hybrid-exchange density functional theory calculations are used to explore the first layer of water at model oxide surfaces, which is an important step for understanding the photocatalytic reactions involved in solar water splitting. By comparing the structure and properties of SnO2(110) and TiO2(110) surfaces in contact with water, the effects of structural and electronic differences on the water chemistry are examined. The dissociative adsorption mode at low coverage (1/7 ML) up to monolayer coverage (1 ML) on both SnO2 and TiO2(110) surfaces is analysed. To investigate further the intermolecular interactions between adjacent adsorbates, monolayer adsorption on each surface is explored in terms of binding energies and bond lengths. Analysis of the water adsorption geometry and energetics shows that the relative stability of water adsorption on SnO2(110) is governed largely by the strength of the chemisorption and hydrogen bonds at the surface of the adsorbate-substrate system. However on TiO2(110), a more complicated scenario of the first layer of water on its surface arises in which there is an interplay between chemisorption, hydrogen bonding and adsorbate-induced atomic displacements in the surface. Furthermore the projected density of states of each surface in contact with a mixture of adsorbed water molecules and adsorbed hydroxyls is presented and sheds some light on the nature of the crystalline chemical bonds as well as on why adsorbed water has often been reported to be unstable on rutile SnO2(110).
Electron gas interacting in a metal, submitted to a strong magnetic field
International Nuclear Information System (INIS)
Alcaraz, Francisco Castilho
1977-01-01
Using the propagator's technique in the grand ensemble developed by Montroll and Ward we investigate the magnetic properties of an interacting electron gas in a strong magnetic field. The free propagator properly constructed shows that the spin paramagnetism does not have a term with strong temperature dependence, contrary to the result of Isihara. Considering the electron density to be constant, the dHVA oscillations in the magnetic susceptibility and sound velocity, considering the effects of first exchange interactions, show only one phase in agreement with experimental result, while Ichimura and Isihara obtained two phases differing by π/2. The effects of first order exchange interactions in the dHVA oscillations of the magnetic susceptibility and sound velocity give rise to an exponential factor in the amplitudes of oscillator (Dingle factor), being the Dingle temperature linearly dependent of the Fermi velocity. The calculations of the ring diagram contribution to the grand partition function, show that the approximation used by Isihara for this calculations is not good and the dHVA oscillations of the contributions from the ring diagrams for the grand partition function have a phase differing by π/2 from that obtained by Isihara. (author)
Observation of Spin-Polarons in a strongly interacting Fermi liquid
Zwierlein, Martin
2009-03-01
We have observed spin-polarons in a highly imbalanced mixture of fermionic atoms using tomographic RF spectroscopy. Feshbach resonances allow to freely tune the interactions between the two spin states involved. A single spin down atom immersed in a Fermi sea of spin up atoms can do one of two things: For strong attraction, it can form a molecule with exactly one spin up partner, but for weaker interaction it will spread its attraction and surround itself with a collection of majority atoms. This spin down atom ``dressed'' with a spin up cloud constitutes the spin-polaron. We have observed a striking spectroscopic signature of this quasi-particle for various interaction strengths, a narrow peak in the spin down spectrum that emerges above a broad background. The narrow width signals a long lifetime of the spin-polaron, much longer than the collision rate with spin up atoms, as it must be for a proper quasi-particle. The peak position allows to directly measure the polaron energy. The broad pedestal at high energies reveals physics at short distances and is thus ``molecule-like'': It is exactly matched by the spin up spectra. The comparison with the area under the polaron peak allows to directly obtain the quasi-particle weight Z. We observe a smooth transition from polarons to molecules. At a critical interaction strength of 1/kFa = 0.7, the polaron peak vanishes and spin up and spin down spectra exactly match, signalling the formation of molecules. This is the same critical interaction strength found earlier to separate a normal Fermi mixture from a superfluid molecular Bose-Einstein condensate. The spin-polarons determine the low-temperature phase diagram of imbalanced Fermi mixtures. In principle, polarons can interact with each other and should, at low enough temperatures, form a superfluid of p-wave pairs. We will present a first indication for interactions between polarons.
Quantum criticality of one-dimensional multicomponent Fermi gas with strongly attractive interaction
International Nuclear Information System (INIS)
He, Peng; Jiang, Yuzhu; Guan, Xiwen; He, Jinyu
2015-01-01
Quantum criticality of strongly attractive Fermi gas with SU(3) symmetry in one dimension is studied via the thermodynamic Bethe ansatz (TBA) equations. The phase transitions driven by the chemical potential μ, effective magnetic field H 1 , H 2 (chemical potential biases) are analyzed at the quantum criticality. The phase diagram and critical fields are analytically determined by the TBA equations in the zero temperature limit. High accurate equations of state, scaling functions are also obtained analytically for the strong interacting gases. The dynamic exponent z=2 and correlation length exponent ν=1/2 read off the universal scaling form. It turns out that the quantum criticality of the three-component gases involves a sudden change of density of states of one cluster state, two or three cluster states. In general, this method can be adapted to deal with the quantum criticality of multicomponent Fermi gases with SU(N) symmetry. (paper)
Studies of the strong and electroweak interactions at the Z0 pole
International Nuclear Information System (INIS)
Hildreth, M.D.
1995-03-01
This thesis presents studies of the strong and electroweak forces, two of the fundamental interactions that govern the behavior of matter at high energies. The authors have used the hadronic decays of Z 0 bosons produced with the unique experimental apparatus of the e + e - Linear Collider at the Stanford Linear Accelerator Center (SLAC) and the SLAC Large Detector (SLD) for these measurements. Employing the precision tracking capabilities of the SLD, they isolated samples of Z 0 events containing primarily the decays of the Z 0 to a chosen quark type. With an inclusive selection technique, they have tested the flavor independence of the strong coupling, α s by measuring the rates of multi-jet production in isolated samples of light (uds), c, and b quark events. They find: α s uds /α s all 0.987 ± 0.027(stat) ± 0.022(syst) ± 0.022(theory), α s c /α s all = 1.012 ± 0.104(stat) ± 0.102(syst) ± 0.096(theory), α s b /α s all = 1.026 ± 0.041(stat) ± 0.030(theory), which implies that the strong interaction is independent of quark flavor within the present experimental sensitivity. They have also measured the extent of parity-violation in the Z 0 c bar c coupling, given by the parameter A c 0 , using a sample of fully and partially reconstructed D* and D + meson decays and the longitudinal polarization of the SLC electron beam. This sample of charm quark events was derived with selection techniques based on their kinematic properties and decay topologies. They find A c 0 = 0.73 ± 0.22(stat) ± 0.10(syst). This value is consistent with that expected in the electroweak standard model of particle interactions
Thermodynamics of strongly interacting system from reparametrized Polyakov-Nambu-Jona-Lasinio model
International Nuclear Information System (INIS)
Bhattacharyya, Abhijit; Ghosh, Sanjay K.; Maity, Soumitra; Raha, Sibaji; Ray, Rajarshi; Saha, Kinkar; Upadhaya, Sudipa
2017-01-01
The Polyakov-Nambu-Jona-Lasinio model has been quite successful in describing various qualitative features of observables for strongly interacting matter, that are measurable in heavy-ion collision experiments. The question still remains on the quantitative uncertainties in the model results. Such an estimation is possible only by contrasting these results with those obtained from rst principles using the lattice QCD framework. Recently a variety of lattice QCD data were reported in the realistic continuum limit. Here we make a first attempt at reparametrizing the model so as to reproduce these lattice data
Atomic wavefunctions probed through strong-field light-matter interaction
Energy Technology Data Exchange (ETDEWEB)
Mairesse, Y; Villeneuve, D M; Corkum, P B; Dudovich, N [Natl Res Council Canada, Ottawa, ON K1A 0R6 (Canada); Shafir, D; Dudovich, N [Weizmann Inst Sci, Dept Phys Complex Syst, IL-76100 Rehovot, (Israel); Mairesse, Y [Univ Bordeaux 1, CELIA, CNRS, UMR 5107, CEA, F-33405 Talence (France)
2009-07-01
Strong-field light-matter interactions can encode the spatial properties of the electronic wavefunctions that contribute to the process. In particular, the broadband harmonic spectra, measured for a series of molecular alignments, can be used to create a tomographic reconstruction of molecular orbitals. Here, we present an extension of the tomography approach to systems that cannot be naturally aligned. We demonstrate this ability by probing the two-dimensional properties of atomic wavefunctions. By manipulating an electron-ion re-collision process, we are able to resolve the symmetry of the atomic wavefunction with high contrast. (authors)
Mishmash, Ryan V.
Experiments on strongly correlated quasi-two-dimensional electronic materials---for example, the high-temperature cuprate superconductors and the putative quantum spin liquids kappa-(BEDT-TTF)2Cu2(CN)3 and EtMe3Sb[Pd(dmit)2]2---routinely reveal highly mysterious quantum behavior which cannot be explained in terms of weakly interacting degrees of freedom. Theoretical progress thus requires the introduction of completely new concepts and machinery beyond the traditional framework of the band theory of solids and its interacting counterpart, Landau's Fermi liquid theory. In full two dimensions, controlled and reliable analytical approaches to such problems are severely lacking, as are numerical simulations of even the simplest of model Hamiltonians due to the infamous fermionic sign problem. Here, we attempt to circumvent some of these difficulties by studying analogous problems in quasi-one dimension. In this lower dimensional setting, theoretical and numerical tractability are on much stronger footing due to the methods of bosonization and the density matrix renormalization group, respectively. Using these techniques, we attack two problems: (1) the Mott transition between a Fermi liquid metal and a quantum spin liquid as potentially directly relevant to the organic compounds kappa-(BEDT-TTF)2Cu 2(CN)3 and EtMe3Sb[Pd(dmit)2] 2 and (2) non-Fermi liquid metals as strongly motivated by the strange metal phase observed in the cuprates. In both cases, we are able to realize highly exotic quantum phases as ground states of reasonable microscopic models. This lends strong credence to respective underlying slave-particle descriptions of the low-energy physics, which are inherently strongly interacting and also unconventional in comparison to weakly interacting alternatives. Finally, working in two dimensions directly, we propose a new slave-particle theory which explains in a universal way many of the intriguing experimental results of the triangular lattice organic spin
Evidence for strong Breit interaction in dielectronic recombination of highly charged heavy ions.
Nakamura, Nobuyuki; Kavanagh, Anthony P; Watanabe, Hirofumi; Sakaue, Hiroyuki A; Li, Yueming; Kato, Daiji; Currell, Fred J; Ohtani, Shunsuke
2008-02-22
Resonant strengths have been measured for dielectronic recombination of Li-like iodine, holmium, and bismuth using an electron beam ion trap. By observing the atomic number dependence of the state-resolved resonant strength, clear experimental evidence has been obtained that the importance of the generalized Breit interaction (GBI) effect on dielectronic recombination increases as the atomic number increases. In particular, it has been shown that the GBI effect is exceptionally strong for the recombination through the resonant state [1s2s(2)2p(1/2)](1).
Volkov basis for simulation of interaction of strong laser pulses and solids
Kidd, Daniel; Covington, Cody; Li, Yonghui; Varga, Kálmán
2018-01-01
An efficient and accurate basis comprised of Volkov states is implemented and tested for time-dependent simulations of interactions between strong laser pulses and crystalline solids. The Volkov states are eigenstates of the free electron Hamiltonian in an electromagnetic field and analytically represent the rapidly oscillating time-dependence of the orbitals, allowing significantly faster time propagation than conventional approaches. The Volkov approach can be readily implemented in plane-wave codes by multiplying the potential energy matrix elements with a simple time-dependent phase factor.
Residual correlation in two-proton interferometry from Λ-proton strong interactions
International Nuclear Information System (INIS)
Wang, Fuqiang
1999-01-01
We investigate the residual effect of Λp strong interactions in pp correlations with one proton from Λ decays. It is found that the residual correlation is about 10% of the Λp correlation strength, and has a broad distribution centered around q≅40 MeV/c. The residual correlation cannot explain the observed structure on the tail of the recently measured pp correlation function in central Pb+Pb collisions by NA49 at the Super Proton Synchrotron. (c) 1999 The American Physical Society
Partial widths of boson resonances in the quark-gluon model of strong interactions
International Nuclear Information System (INIS)
Kaidalov, A.B.; Volkovitsky, P.E.
1981-01-01
The quark-gluon model of strong interactions based on the topological expansion and the string model ib used for the calculation of the partial widths of boson resonances in the channels with two pseudoscalar mesons. The partial widths of mesons with arbitrary spins lying on the vector and tensor Regge trajectories are expressed in terms of the only rho-meson width. The violation of SU(3) symmetry increases with the growth of the spin of the resonance. The theoretical predictions are in a good agreement with experimental data [ru
Ovchinnikov, Sergey G.; Makarov, Ilya A.; Kozlov, Peter A.
2017-03-01
In this work dependences of the electron band structure and spectral function in the HTSC cuprates on magnitude of electron-phonon interaction (EPI) and temperature are investigated. We use three-band p-d model with diagonal and offdiagonal EPI with breathing and buckling phonon mode in the frameworks of polaronic version of the generalized tight binding (GTB) method. The polaronic quasiparticle excitation in the system with EPI within this approach is formed by a hybridization of the local multiphonon Franck-Condon excitations with lower and upper Hubbard bands. Increasing EPI leads to transfer of spectral weight to high-energy multiphonon excitations and broadening of the spectral function. Temperature effects are taken into account by occupation numbers of local excited polaronic states and variations in the magnitude of spin-spin correlation functions. Increasing the temperature results in band structure reconstruction, spectral weight redistribution, broadening of the spectral function peak at the top of the valence band and the decreasing of the peak intensity. The effect of EPI with two phonon modes on the polaron spectral function is discussed.
Mechanism for thermal relic dark matter of strongly interacting massive particles.
Hochberg, Yonit; Kuflik, Eric; Volansky, Tomer; Wacker, Jay G
2014-10-24
We present a new paradigm for achieving thermal relic dark matter. The mechanism arises when a nearly secluded dark sector is thermalized with the standard model after reheating. The freeze-out process is a number-changing 3→2 annihilation of strongly interacting massive particles (SIMPs) in the dark sector, and points to sub-GeV dark matter. The couplings to the visible sector, necessary for maintaining thermal equilibrium with the standard model, imply measurable signals that will allow coverage of a significant part of the parameter space with future indirect- and direct-detection experiments and via direct production of dark matter at colliders. Moreover, 3→2 annihilations typically predict sizable 2→2 self-interactions which naturally address the "core versus cusp" and "too-big-to-fail" small-scale structure formation problems.
Introduction to unified theories of weak, electromagnetic and strong interactions - SU(5)
International Nuclear Information System (INIS)
Billoire, Alain; Morel, Andre.
1980-11-01
These notes correspond to a series of lectures given at Salay during winter 1979-1980. They are meant to be an introduction to the so-called grand unified theories of weak, electromagnetic and strong interactions. In a first part, we recall in a very elementary way the standard SU(2) model of electroweak interactions, putting the emphasis on the questions which are left open by this model and which unified theories help to answer. In part II, we explain in a systematic way how unified theories can be constructed, and develop the SU(5) model in great detail. Other models, like SO(10) and E 6 , are not presented, because SU(5) is the simplest one and has been subject to the deepest investigations up to now. Also it appears that most concepts and general results are not specific to any particular symmetry group [fr
International Nuclear Information System (INIS)
Basini, G.
2003-01-01
Asymptotic freedom, as a natural result of a theory based on a general approach, derived by a new interpretation of phenomena like the EPR paradox, the black-hole formation and the absence of primary cosmic antimatter is presented. In this approach, conservation laws are considered always and absolutely valid, leading to the possibility of topology changes, and recovering the mutual influence between fundamental forces. Moreover, a new consideration of time arrows leads to asymptotic freedom as a necessary consequence. In fact, asymptotic freedom of strong interactions seems to be a feature common also to gravitational interaction, if induced-gravity theories (t → ∞) are taken into account and a symmetric-time dynamics is recovered in the light of a general conservation principle. (authors)
Energy Technology Data Exchange (ETDEWEB)
Basini, G. [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati; Capozziello, S. [E.R. Caianiello, Dipt. di Fisica, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Napoli, Universita di Salerno, Boronissi, SA (Italy)
2003-09-01
Asymptotic freedom, as a natural result of a theory based on a general approach, derived by a new interpretation of phenomena like the EPR paradox, the black-hole formation and the absence of primary cosmic antimatter is presented. In this approach, conservation laws are considered always and absolutely valid, leading to the possibility of topology changes, and recovering the mutual influence between fundamental forces. Moreover, a new consideration of time arrows leads to asymptotic freedom as a necessary consequence. In fact, asymptotic freedom of strong interactions seems to be a feature common also to gravitational interaction, if induced-gravity theories (t {yields} {infinity}) are taken into account and a symmetric-time dynamics is recovered in the light of a general conservation principle. (authors)
Quasiparticle Energy in a Strongly Interacting Homogeneous Bose-Einstein Condensate.
Lopes, Raphael; Eigen, Christoph; Barker, Adam; Viebahn, Konrad G H; Robert-de-Saint-Vincent, Martin; Navon, Nir; Hadzibabic, Zoran; Smith, Robert P
2017-05-26
Using two-photon Bragg spectroscopy, we study the energy of particlelike excitations in a strongly interacting homogeneous Bose-Einstein condensate, and observe dramatic deviations from Bogoliubov theory. In particular, at large scattering length a the shift of the excitation resonance from the free-particle energy changes sign from positive to negative. For an excitation with wave number q, this sign change occurs at a≈4/(πq), in agreement with the Feynman energy relation and the static structure factor expressed in terms of the two-body contact. For a≳3/q we also see a breakdown of this theory, and better agreement with calculations based on the Wilson operator product expansion. Neither theory explains our observations across all interaction regimes, inviting further theoretical efforts.
Many-body Anderson localization of strongly interacting bosons in random lattices
International Nuclear Information System (INIS)
Katzer, Roman
2015-05-01
In the present work, we investigate the problem of many-body localization of strongly interacting bosons in random lattices within the disordered Bose-Hubbard model. This involves treating both the local Mott-Hubbard physics as well as the non-local quantum interference processes, which give rise to the phenomenon of Anderson localization, within the same theory. In order to determine the interaction induced transition to the Mott insulator phase, it is necessary to treat the local particle interaction exactly. Therefore, here we use a mean-field approach that approximates only the kinetic term of the Hamiltonian. This way, the full problem of interacting bosons on a random lattice is reduced to a local problem of a single site coupled to a particle bath, which has to be solved self-consistently. In accordance to previous works, we find that a finite disorder width leads to a reduced size of the Mott insulating regions. The transition from the superfluid phase to the Bose glass phase is driven by the non-local effect of Anderson localization. In order to describe this transition, one needs to work within a theory that is non-local as well. Therefore, here we introduce a new approach to the problem. Based on the results for the local excitation spectrum obtained within the mean-field theory, we reduce the full, interacting model to an effective, non-interacting model by applying a truncation scheme to the Hilbert space. Evaluating the long-ranged current density within this approximation, we identify the transition from the Bose glass to the superfluid phase with the Anderson transition of the effective model. Resolving this transition using the self-consistent theory of localization, we obtain the full phase diagram of the disordered Bose-Hubbard model in the regime of strong interaction and larger disorder. In accordance to the theorem of inclusions, we find that the Mott insulator and the superfluid phase are always separated by the compressible, but insulating
Effective model with strong Kitaev interactions for α -RuCl3
Suzuki, Takafumi; Suga, Sei-ichiro
2018-04-01
We use an exact numerical diagonalization method to calculate the dynamical spin structure factors of three ab initio models and one ab initio guided model for a honeycomb-lattice magnet α -RuCl3 . We also use thermal pure quantum states to calculate the temperature dependence of the heat capacity, the nearest-neighbor spin-spin correlation function, and the static spin structure factor. From the results obtained from these four effective models, we find that, even when the magnetic order is stabilized at low temperature, the intensity at the Γ point in the dynamical spin structure factors increases with increasing nearest-neighbor spin correlation. In addition, we find that the four models fail to explain heat-capacity measurements whereas two of the four models succeed in explaining inelastic-neutron-scattering experiments. In the four models, when temperature decreases, the heat capacity shows a prominent peak at a high temperature where the nearest-neighbor spin-spin correlation function increases. However, the peak temperature in heat capacity is too low in comparison with that observed experimentally. To address these discrepancies, we propose an effective model that includes strong ferromagnetic Kitaev coupling, and we show that this model quantitatively reproduces both inelastic-neutron-scattering experiments and heat-capacity measurements. To further examine the adequacy of the proposed model, we calculate the field dependence of the polarized terahertz spectra, which reproduces the experimental results: the spin-gapped excitation survives up to an onset field where the magnetic order disappears and the response in the high-field region is almost linear. Based on these numerical results, we argue that the low-energy magnetic excitation in α -RuCl3 is mainly characterized by interactions such as off-diagonal interactions and weak Heisenberg interactions between nearest-neighbor pairs, rather than by the strong Kitaev interactions.
Desensitization and recovery of metastable intermolecular composites
Busse, James R [South Fork, CO; Dye, Robert C [Los Alamos, NM; Foley, Timothy J [Los Alamos, NM; Higa, Kelvin T [Ridgecrest, CA; Jorgensen, Betty S [Jemez Springs, NM; Sanders, Victor E [White Rock, NM; Son, Steven F [Los Alamos, NM
2010-09-07
A method to substantially desensitize a metastable intermolecular composite material to electrostatic discharge and friction comprising mixing the composite material with an organic diluent and removing enough organic diluent from the mixture to form a mixture with a substantially putty-like consistency, as well as a concomitant method of recovering the metastable intermolecular composite material.
Simulation of Quantum Many-Body Dynamics for Generic Strongly-Interacting Systems
Meyer, Gregory; Machado, Francisco; Yao, Norman
2017-04-01
Recent experimental advances have enabled the bottom-up assembly of complex, strongly interacting quantum many-body systems from individual atoms, ions, molecules and photons. These advances open the door to studying dynamics in isolated quantum systems as well as the possibility of realizing novel out-of-equilibrium phases of matter. Numerical studies provide insight into these systems; however, computational time and memory usage limit common numerical methods such as exact diagonalization to relatively small Hilbert spaces of dimension 215 . Here we present progress toward a new software package for dynamical time evolution of large generic quantum systems on massively parallel computing architectures. By projecting large sparse Hamiltonians into a much smaller Krylov subspace, we are able to compute the evolution of strongly interacting systems with Hilbert space dimension nearing 230. We discuss and benchmark different design implementations, such as matrix-free methods and GPU based calculations, using both pre-thermal time crystals and the Sachdev-Ye-Kitaev model as examples. We also include a simple symbolic language to describe generic Hamiltonians, allowing simulation of diverse quantum systems without any modification of the underlying C and Fortran code.
International Nuclear Information System (INIS)
Recami, E.; Tonin Zanchin, V.; Martinez, J.M.
1986-01-01
A unified geometrical approach to strong and gravitational interactions has been recently proposed, based on the classical methods of General Relativity. According to it, hadrons can be regarded as black-hole type solutions of new field equations describing two tensorial metric-field (the ordinary gravitational field, and the strong one). In this paper, we first seize the opportunity for an improved exposition of some elements of the theory relevant to our present scope. Secondly, by extending the Bekenstein-Hawking thermodynamics to the above mentioned strong black-holes (SBH), it is shown: 1) that SBH thermodynamics seems to require a new expansion of our cosmos after its Big Crunch (i.e. that a recontraction of our cosmos has to be followed by a new creation); 2) that a collapsing star with mass M approximately in the range 3 to 5 solar masses, once reached the neutron-star density, could re-explode tending to form a (radiating) object with a diameter of the order of 1 light-day: thus failing to create a gravitational black-hole
Tubman, Norm; Whaley, Birgitta
The development of exponential scaling methods has seen great progress in tackling larger systems than previously thought possible. One such technique, full configuration interaction quantum Monte Carlo, allows exact diagonalization through stochastically sampling of determinants. The method derives its utility from the information in the matrix elements of the Hamiltonian, together with a stochastic projected wave function, which are used to explore the important parts of Hilbert space. However, a stochastic representation of the wave function is not required to search Hilbert space efficiently and new deterministic approaches have recently been shown to efficiently find the important parts of determinant space. We shall discuss the technique of Adaptive Sampling Configuration Interaction (ASCI) and the related heat-bath Configuration Interaction approach for ground state and excited state simulations. We will present several applications for strongly correlated Hamiltonians. This work was supported through the Scientific Discovery through Advanced Computing (SciDAC) program funded by the U.S. Department of Energy, Office of Science, Advanced Scientific Computing Research and Basic Energy Sciences.
Studies of the strong and electroweak interactions at the Z^{0} pole
Energy Technology Data Exchange (ETDEWEB)
Hildreth, Michael Douglas [Stanford Univ., CA (United States)
1995-03-01
This thesis presents studies of the strong and electroweak forces, two of the fundamental interactions that govern the behavior of matter at high energies. The authors have used the hadronic decays of Z^{0} bosons produced with the unique experimental apparatus of the e^{+}e^{-} Linear Collider at the Stanford Linear Accelerator Center (SLAC) and the SLAC Large Detector (SLD) for these measurements. Employing the precision tracking capabilities of the SLD, they isolated samples of Z^{0} events containing primarily the decays of the Z^{0} to a chosen quark type. With an inclusive selection technique, they have tested the flavor independence of the strong coupling, α_{s} by measuring the rates of multi-jet production in isolated samples of light (uds), c, and b quark events. They find: α$s\\atop{uds}$/α$s\\atop{all}$ 0.987 ± 0.027(stat) ± 0.022(syst) ± 0.022(theory), α$c\\atop{s}$/α$all\\atop{s}$ = 1.012 ± 0.104(stat) ± 0.102(syst) ± 0.096(theory), α$b\\atop{s}$/α$all\\atop{s}$ = 1.026 {+-} 0.041(stat) ± 0.030(theory), which implies that the strong interaction is independent of quark flavor within the present experimental sensitivity. They have also measured the extent of parity-violation in the Z^{0} c$\\bar{c}$ coupling, given by the parameter A $0\\atop{c}$, using a sample of fully and partially reconstructed D* and D^{+} meson decays and the longitudinal polarization of the SLC electron beam. This sample of charm quark events was derived with selection techniques based on their kinematic properties and decay topologies. They find A$0\\atop{c}$ = 0.73 ± 0.22(stat) ± 0.10(syst). This value is consistent with that expected in the electroweak standard model of particle interactions.
Effects of strong and electromagnetic correlations on neutrino interactions in dense matter
International Nuclear Information System (INIS)
Reddy, S.; Prakash, M.; Lattimer, J.M.; Reddy, S.; Pons, J.A.
1999-01-01
An extensive study of the effects of correlations on both charged and neutral current weak interaction rates in dense matter is performed. Both strong and electromagnetic correlations are considered. The propagation of particle-hole interactions in the medium plays an important role in determining the neutrino mean free paths. The effects due to Pauli blocking and density, spin, and isospin correlations in the medium significantly reduce the neutrino cross sections. As a result of the lack of experimental information at high density, these correlations are necessarily model dependent. For example, spin correlations in nonrelativistic models are found to lead to larger suppressions of neutrino cross sections compared to those of relativistic models. This is due to the tendency of the nonrelativistic models to develop spin instabilities. Notwithstanding the above caveats, and the differences between nonrelativistic and relativistic approaches such as the spin- and isospin-dependent interactions and the nucleon effective masses, suppressions of order 2 - 3, relative to the case in which correlations are ignored, are obtained. Neutrino interactions in dense matter are especially important for supernova and early neutron star evolution calculations. The effects of correlations for protoneutron star evolution are calculated. Large effects on the internal thermodynamic properties of protoneutron stars, such as the temperature, are found. These translate into significant early enhancements in the emitted neutrino energies and fluxes, especially after a few seconds. At late times, beyond about 10 s, the emitted neutrino fluxes decrease more rapidly compared to simulations without the effects of correlations, due to the more rapid onset of neutrino transparency in the protoneutron star. copyright 1999 The American Physical Society
DEFF Research Database (Denmark)
Loft, Niels Jakob Søe; Kristensen, Lasse Bjørn; Thomsen, Anders
2016-01-01
We consider a one-dimensional system of particles with strong zero-range interactions. This system can be mapped onto a spin chain of the Heisenberg type with exchange coefficients that depend on the external trap. In this paper, we present an algorithm that can be used to compute these exchange...... coefficients. We introduce an open source code CONAN (Coefficients of One-dimensional N-Atom Networks) which is based on this algorithm. CONAN works with arbitrary external potentials and we have tested its reliability for system sizes up to around 35 particles. As illustrative examples, we consider a harmonic...... trap and a box trap with a superimposed asymmetric tilted potential. For these examples, the computation time typically scales with the number of particles as O(N3.5±0.4). Computation times are around 10 s for N=10 particles and less than 10 min for N=20 particles....
Fluctuation instability of the Dirac Sea in quark models of strong interactions
Zinovjev, G. M.; Molodtsov, S. V.
2016-03-01
A number of exactly integrable (quark) models of quantum field theory that feature an infinite correlation length are considered. An instability of the standard vacuum quark ensemble, a Dirac sea (in spacetimes of dimension higher than three), is highlighted. It is due to a strong ground-state degeneracy, which, in turn, stems from a special character of the energy distribution. In the case where the momentumcutoff parameter tends to infinity, this distribution becomes infinitely narrow and leads to large (unlimited) fluctuations. A comparison of the results for various vacuum ensembles, including a Dirac sea, a neutral ensemble, a color superconductor, and a Bardeen-Cooper-Schrieffer (BCS) state, was performed. In the presence of color quark interaction, a BCS state is unambiguously chosen as the ground state of the quark ensemble.
Fluctuation instability of the Dirac Sea in quark models of strong interactions
International Nuclear Information System (INIS)
Zinovjev, G. M.; Molodtsov, S. V.
2016-01-01
A number of exactly integrable (quark) models of quantum field theory that feature an infinite correlation length are considered. An instability of the standard vacuum quark ensemble, a Dirac sea (in spacetimes of dimension higher than three), is highlighted. It is due to a strong ground-state degeneracy, which, in turn, stems from a special character of the energy distribution. In the case where the momentumcutoff parameter tends to infinity, this distribution becomes infinitely narrow and leads to large (unlimited) fluctuations. A comparison of the results for various vacuum ensembles, including a Dirac sea, a neutral ensemble, a color superconductor, and a Bardeen–Cooper–Schrieffer (BCS) state, was performed. In the presence of color quark interaction, a BCS state is unambiguously chosen as the ground state of the quark ensemble.
Fluctuation instability of the Dirac Sea in quark models of strong interactions
Energy Technology Data Exchange (ETDEWEB)
Zinovjev, G. M., E-mail: Gennady.Zinovjev@cern.ch [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine); Molodtsov, S. V. [Joint Institute for Nuclear Research (Russian Federation)
2016-03-15
A number of exactly integrable (quark) models of quantum field theory that feature an infinite correlation length are considered. An instability of the standard vacuum quark ensemble, a Dirac sea (in spacetimes of dimension higher than three), is highlighted. It is due to a strong ground-state degeneracy, which, in turn, stems from a special character of the energy distribution. In the case where the momentumcutoff parameter tends to infinity, this distribution becomes infinitely narrow and leads to large (unlimited) fluctuations. A comparison of the results for various vacuum ensembles, including a Dirac sea, a neutral ensemble, a color superconductor, and a Bardeen–Cooper–Schrieffer (BCS) state, was performed. In the presence of color quark interaction, a BCS state is unambiguously chosen as the ground state of the quark ensemble.
Electron-muon correlation as a new probe of strongly interacting quark-gluon plasma
International Nuclear Information System (INIS)
Akamatsu, Yukinao; Hatsuda, Tetsuo; Hirano, Tetsufumi
2009-01-01
As a new and clean probe to the strongly interacting quark-gluon plasma (sQGP), we propose an azimuthal correlation of an electron and a muon that originate from the semileptonic decay of charm and bottom quarks. By solving the Langevin equation for the heavy quarks under the hydrodynamic evolution of the hot plasma, we show that substantial quenching of the away-side peak in the electron-muon correlation can be seen if the sQGP drag force acting on heavy quarks is large enough as suggested from the gauge/gravity correspondence. The effect could be detected in high-energy heavy ion collisions at the Relativistic Heavy Ion Collider and the Large Hadron Collider.
Thermal dark matter co-annihilating with a strongly interacting scalar
Biondini, S.; Laine, M.
2018-04-01
Recently many investigations have considered Majorana dark matter co-annihilating with bound states formed by a strongly interacting scalar field. However only the gluon radiation contribution to bound state formation and dissociation, which at high temperatures is subleading to soft 2 → 2 scatterings, has been included. Making use of a non-relativistic effective theory framework and solving a plasma-modified Schrödinger equation, we address the effect of soft 2 → 2 scatterings as well as the thermal dissociation of bound states. We argue that the mass splitting between the Majorana and scalar field has in general both a lower and an upper bound, and that the dark matter mass scale can be pushed at least up to 5…6TeV.
Phase transitions, nonequilibrium dynamics, and critical behavior of strongly interacting systems
International Nuclear Information System (INIS)
Mottola, E.; Bhattacharya, T.; Cooper, F.
1998-01-01
This is the final report of a three-year, Laboratory Directed Research and Development project at Los Alamos National Laboratory. In this effort, large-scale simulations of strongly interacting systems were performed and a variety of approaches to the nonequilibrium dynamics of phase transitions and critical behavior were investigated. Focus areas included (1) the finite-temperature quantum chromodynamics phase transition and nonequilibrium dynamics of a new phase of matter (the quark-gluon plasma) above the critical temperature, (2) nonequilibrium dynamics of a quantum fields using mean field theory, and (3) stochastic classical field theoretic models with applications to spinodal decomposition and structural phase transitions in a variety of systems, such as spin chains and shape memory alloys
Phase transitions, nonequilibrium dynamics, and critical behavior of strongly interacting systems
Energy Technology Data Exchange (ETDEWEB)
Mottola, E.; Bhattacharya, T.; Cooper, F. [and others
1998-12-31
This is the final report of a three-year, Laboratory Directed Research and Development project at Los Alamos National Laboratory. In this effort, large-scale simulations of strongly interacting systems were performed and a variety of approaches to the nonequilibrium dynamics of phase transitions and critical behavior were investigated. Focus areas included (1) the finite-temperature quantum chromodynamics phase transition and nonequilibrium dynamics of a new phase of matter (the quark-gluon plasma) above the critical temperature, (2) nonequilibrium dynamics of a quantum fields using mean field theory, and (3) stochastic classical field theoretic models with applications to spinodal decomposition and structural phase transitions in a variety of systems, such as spin chains and shape memory alloys.
Directory of Open Access Journals (Sweden)
Szymański Maciej
2015-01-01
Full Text Available In this article, the analysis of baryon-antibaryon femtoscopic correlations is presented. In particular, it is shown that taking into account residual correlations is crucial for the description of pΛ¯$\\bar \\Lambda $ and p̄Λ correlation functions measured by the STAR experiment in Au–Au collisions at the centre-of-mass energy per nucleon pair √sNN = 200 GeV. This approach enables to obtain pΛ¯$\\bar \\Lambda $ (p̄Λ source size consistent with the sizes extracted from correlations in pΛ (p̄Λ¯$\\bar \\Lambda $ and lighter pair systems as well as with model predictions. Moreover, with this analysis it is possible to derive the unknown parameters of the strong interaction potential for baryon-antibaryon pairs under several assumptions.
Particle-Hole Character of the Higgs and Goldstone Modes in Strongly Interacting Lattice Bosons
Di Liberto, M.; Recati, A.; Trivedi, N.; Carusotto, I.; Menotti, C.
2018-02-01
We study the low-energy excitations of the Bose-Hubbard model in the strongly interacting superfluid phase using a Gutzwiller approach. We extract the single-particle and single-hole excitation amplitudes for each mode and report emergent mode-dependent particle-hole symmetry on specific arc-shaped lines in the phase diagram connecting the well-known Lorentz-invariant limits of the Bose-Hubbard model. By tracking the in-phase particle-hole symmetric oscillations of the order parameter, we provide an answer to the long-standing question about the fate of the pure amplitude Higgs mode away from the integer-density critical point. Furthermore, we point out that out-of-phase symmetric oscillations in the gapless Goldstone mode are responsible for a full suppression of the condensate density oscillations. Possible detection protocols are also discussed.
Orientation correlation and intermolecular structure of GeCl4, VCl4 and other tetrachloride liquids
International Nuclear Information System (INIS)
Nath, P.P.; Sarkar, S.; Joarder, R.N.
2007-01-01
The intermolecular structure and correlation of GeCl 4 , VCl 4 and other tetrachloride liquids can be well described by Misawa's orientation correlation model originally applied to liquid CCl 4 . The model supports on average a specific 'corner' to 'face' correlation, but evidently very different from 'Apollo' type model. The Misawa model appears to work, in some respect, even better than reference interaction site model (RISM) used for long to describe intermolecular structure of such molecular systems. The test and comparison are made through the calculation of small asymmetric part of the intermolecular structure and evaluation of partial atom-atom distribution functions
New precision era of experiments on strong interaction with strangeness at DAFNE/LNF-INFN
Directory of Open Access Journals (Sweden)
Ishiwatari T.
2014-03-01
Full Text Available The strong-interaction shifts and widths of kaonic hydrogen, deuterium, 3He, and 4He were measured in the SIDDHARTA experiment. The most precise values of the shift and width of the kaonic hydrogen 1s state were determined to be ϵ1s = −283 ± 36(stat±6(syst eV and Γ1s = 541±89(stat±22(syst eV. The upper limit of the kaonic deuterium Kα yield was found to be ≤ 0.39%. In addition, the shifts and widths of the kaonic 3He and 4He 2p states were determined to be ϵ2p(3He = −2 ± 2(stat ± 4(syst eV and Γ2p(3He = 6 ± 6(stat ± 7(syst eV; ϵ2p(4He = +5 ± 3(stat ± 4(syst eV and Γ2p(4He = 14 ± 8(stat ± 5(syst eV. These values are important for the constraints of the low-energy K¯N$\\bar KN$ interaction in theoretical approaches.
Debecker, Sara; Dinh, Khuong V; Stoks, Robby
2017-02-21
As contaminants are often more toxic at higher temperatures, predicting their impact under global warming remains a key challenge for ecological risk assessment. Ignoring delayed effects, synergistic interactions between contaminants and warming, and differences in sensitivity across species' ranges could lead to an important underestimation of the risks. We addressed all three mechanisms by studying effects of larval exposure to zinc and warming before, during, and after metamorphosis in Ischnura elegans damselflies from high- and low-latitude populations. By integrating these mechanisms into a single study, we could identify two novel patterns. First, during exposure zinc did not affect survival, whereas it induced mild to moderate postexposure mortality in the larval stage and at metamorphosis, and very strongly reduced adult lifespan. This severe delayed effect across metamorphosis was especially remarkable in high-latitude animals, as they appeared almost insensitive to zinc during the larval stage. Second, the well-known synergism between metals and warming was manifested not only during the larval stage but also after metamorphosis, yet notably only in low-latitude damselflies. These results highlight that a more complete life-cycle approach that incorporates the possibility of delayed interactions between contaminants and warming in a geographical context is crucial for a more realistic risk assessment in a warming world.
Competing Intramolecular vs. Intermolecular Hydrogen Bonds in Solution
Directory of Open Access Journals (Sweden)
Peter I. Nagy
2014-10-01
Full Text Available A hydrogen bond for a local-minimum-energy structure can be identified according to the definition of the International Union of Pure and Applied Chemistry (IUPAC recommendation 2011 or by finding a special bond critical point on the density map of the structure in the framework of the atoms-in-molecules theory. Nonetheless, a given structural conformation may be simply favored by electrostatic interactions. The present review surveys the in-solution competition of the conformations with intramolecular vs. intermolecular hydrogen bonds for different types of small organic molecules. In their most stable gas-phase structure, an intramolecular hydrogen bond is possible. In a protic solution, the intramolecular hydrogen bond may disrupt in favor of two solute-solvent intermolecular hydrogen bonds. The balance of the increased internal energy and the stabilizing effect of the solute-solvent interactions regulates the new conformer composition in the liquid phase. The review additionally considers the solvent effects on the stability of simple dimeric systems as revealed from molecular dynamics simulations or on the basis of the calculated potential of mean force curves. Finally, studies of the solvent effects on the type of the intermolecular hydrogen bond (neutral or ionic in acid-base complexes have been surveyed.
Numerical simulation of wave-current interaction under strong wind conditions
Larrañaga, Marco; Osuna, Pedro; Ocampo-Torres, Francisco Javier
2017-04-01
Although ocean surface waves are known to play an important role in the momentum and other scalar transfer between the atmosphere and the ocean, most operational numerical models do not explicitly include the terms of wave-current interaction. In this work, a numerical analysis about the relative importance of the processes associated with the wave-current interaction under strong off-shore wind conditions in Gulf of Tehuantepec (the southern Mexican Pacific) was carried out. The numerical system includes the spectral wave model WAM and the 3D hydrodynamic model POLCOMS, with the vertical turbulent mixing parametrized by the kappa-epsilon closure model. The coupling methodology is based on the vortex-force formalism. The hydrodynamic model was forced at the open boundaries using the HYCOM database and the wave model was forced at the open boundaries by remote waves from the southern Pacific. The atmospheric forcing for both models was provided by a local implementation of the WRF model, forced at the open boundaries using the CFSR database. The preliminary analysis of the model results indicates an effect of currents on the propagation of the swell throughout the study area. The Stokes-Coriolis term have an impact on the transient Ekman transport by modifying the Ekman spiral, while the Stokes drift has an effect on the momentum advection and the production of TKE, where the later induces a deepening of the mixing layer. This study is carried out in the framework of the project CONACYT CB-2015-01 255377 and RugDiSMar Project (CONACYT 155793).
International Nuclear Information System (INIS)
Belvedere, Riccardo; Pugliese, Daniela; Rueda, Jorge A.; Ruffini, Remo; Xue, She-Sheng
2012-01-01
We formulate the equations of equilibrium of neutron stars taking into account strong, weak, electromagnetic, and gravitational interactions within the framework of general relativity. The nuclear interactions are described by the exchange of the σ, ω, and ρ virtual mesons. The equilibrium conditions are given by our recently developed theoretical framework based on the Einstein–Maxwell–Thomas–Fermi equations along with the constancy of the general relativistic Fermi energies of particles, the “Klein potentials”, throughout the configuration. The equations are solved numerically in the case of zero temperatures and for selected parameterizations of the nuclear models. The solutions lead to a new structure of the star: a positively charged core at supranuclear densities surrounded by an electronic distribution of thickness ∼ℏ/(m e c)∼10 2 ℏ/(m π c) of opposite charge, as well as a neutral crust at lower densities. Inside the core there is a Coulomb potential well of depth ∼m π c 2 /e. The constancy of the Klein potentials in the transition from the core to the crust, imposes the presence of an overcritical electric field ∼(m π /m e ) 2 E c , the critical field being E c =m e 2 c 3 /(eℏ). The electron chemical potential and the density decrease, in the boundary interface, until values μ e crust e core and ρ crust core . For each central density, an entire family of core–crust interface boundaries and, correspondingly, an entire family of crusts with different mass and thickness, exist. The configuration with ρ crust =ρ drip ∼4.3×10 11 gcm −3 separates neutron stars with and without inner crust. We present here the novel neutron star mass–radius for the especial case ρ crust =ρ drip and compare and contrast it with the one obtained from the traditional Tolman–Oppenheimer–Volkoff treatment.
Introduction to gauge theories of the strong, weak, and electromagnetic interactions
International Nuclear Information System (INIS)
Quigg, C.
1980-07-01
The plan of these notes is as follows. Chapter 1 is devoted to a brief evocative review of current beliefs and prejudices that form the context for the discussion to follow. The idea of Gauge Invariance is introduced in Chapter 2, and the connection between conservation laws and symmetries of the Lagrangian is recalled. Non-Abelian gauge field theories are constructed in Chapter 3, by analogy with the familiar case of electromagnetism. The Yang-Mills theory based upon isospin symmetry is constructed explicitly, and the generalization is made to other gauge groups. Chapter 4 is concerned with spontaneous symmetry breaking and the phenomena that occur in the presence or absence of local gauge symmetries. The existence of massless scalar fields (Goldstone particles) and their metamorphosis by means of the Higgs mechanism are illustrated by simple examples. The Weinberg-Salam model is presented in Chapter 5, and a brief resume of applications to experiment is given. Quantum Chromodynamics, the gauge theory of colored quarks and gluons, is developed in Chapter 6. Asymptotic freedom is derived schematically, and a few simple applications of perturbative QCD ae exhibited. Details of the conjectured confinement mechanism are omitted. The strategy of grand unified theories of the strong, weak, and electromagnetic interactions is laid out in Chapter 7. Some properties and consequences of the minimal unifying group SU(5) are presented, and the gauge hierarchy problem is introduced in passing. The final chapter contains an essay on the current outlook: aspirations, unanswered questions, and bold scenarios
Strong interactions between learned helplessness and risky decision-making in a rat gambling model.
Nobrega, José N; Hedayatmofidi, Parisa S; Lobo, Daniela S
2016-11-18
Risky decision-making is characteristic of depression and of addictive disorders, including pathological gambling. However it is not clear whether a propensity to risky choices predisposes to depressive symptoms or whether the converse is the case. Here we tested the hypothesis that rats showing risky decision-making in a rat gambling task (rGT) would be more prone to depressive-like behaviour in the learned helplessness (LH) model. Results showed that baseline rGT choice behaviour did not predict escape deficits in the LH protocol. In contrast, exposure to the LH protocol resulted in a significant increase in risky rGT choices on retest. Unexpectedly, control rats subjected only to escapable stress in the LH protocol showed a subsequent decrease in riskier rGT choices. Further analyses indicated that the LH protocol affected primarily rats with high baseline levels of risky choices and that among these it had opposite effects in rats exposed to LH-inducing stress compared to rats exposed only to the escape trials. Together these findings suggest that while baseline risky decision making may not predict LH behaviour it interacts strongly with LH conditions in modulating subsequent decision-making behaviour. The suggested possibility that stress controllability may be a key factor should be further investigated.
Inhomogeneous chiral symmetry breaking in isospin-asymmetric strong-interaction matter
Energy Technology Data Exchange (ETDEWEB)
Nowakowski, Daniel
2017-07-01
In this thesis we investigate the effects of an isospin asymmetry on inhomogeneous chiral symmetry breaking phases, which are characterized by spatially modulated quarkantiquark condensates. In order to determine the relevance of such phases for the phase diagram of strong-interaction matter, a two-flavor Nambu-Jona-Lasinio model is used to study the properties of the ground state of the system. Confirming the presence of inhomogeneous chiral symmetry breaking in isospin-asymmetric matter for a simple Chiral Density Wave, we generalize the modulation of the quark-antiquark pairs to more complicated shapes and study the effects of different degrees of flavor-mixing on the inhomogeneous phase at non-zero isospin asymmetry. Then, we investigate the occurrence of crystalline chiral symmetry breaking phases in charge-neutral matter, from which we determine the influence of crystalline phases on a quark star by calculating mass-radius sequences. Finally, our model is extended through color-superconducting phases and we study the interplay of these phases with inhomogeneous chiral-symmetry breaking at non-vanishing isospin asymmetry, before we discuss our findings.
Electron-photon and electron-electron interactions in the presence of strong electromagnetic fields
International Nuclear Information System (INIS)
Surzhykov, A.; Fritzsche, S.; Stoehlker, Th.
2010-01-01
During the last decade, photon emission from highly-charged, heavy ions has been in the focus of intense studies at the GSI accelerator and storage ring facility in Darmstadt. These studies have revealed unique information about the electron-electron and electron-photon interactions in the presence of extremely strong nuclear fields. Apart from the radiative electron capture processes, characteristic photon emission following collisional excitation of projectile ions has also attracted much interest. In this contribution, we summarize the recent theoretical studies on the production of excited ionic states and their subsequent radiative decay. We will pay special attention to the angular and polarization properties of Kα emission from helium-like ions produced by means of dielectronic recombination. The results obtained for this (resonant) capture process will be compared with the theoretical predictions for the characteristic X-rays following Coulomb excitation and radiative recombination of few-electron, heavy ions. Work is supported by Helmholtz Association and GSl under the project VH-NG--421. (author)
Compact X-ray sources. Simulating the electron/strong laser interaction
Energy Technology Data Exchange (ETDEWEB)
Hartin, Anthony [DESY, CFEL, Hamburg (Germany)
2016-07-01
The collision of an intense laser with an electron bunch can be used to produce X-rays via the inverse Compton scattering (ICS) mechanism. The ICS can be simulated via either a classical theory in which electrons and photons are treated in terms of classical electromagnetic waves - or a quantum theory in which charged particles interact with strong electromagnetic fields. The laser intensity used in a practical ICS collision is likely to be at such a level that quantum effects may be significant and the use of quantum theory may become a necessity. A simulation study is presented here comparing the classical and quantum approaches to the ICS. A custom particle-in-cell (PIC) software code, with photon generation by monte carlo of the exact quantum transition probability is used to simulate the quantum treatment. Peak resonant energies and the angular distribution of the X-rays are obtained and compared with those predicted by the classical theory. The conditions under which significant differences between the two theories emerges is obtained.
Lattice QCD results on soft and hard probes of strongly interacting matter
Kaczmarek, Olaf
2017-11-01
We present recent results from lattice QCD relevant for the study of strongly interacting matter as it is produced in heavy ion collision experiments. The equation of state at non-vanishing density from a Taylor expansion up to 6th order will be discussed for a strangeness neutral system and using the expansion coefficients of the series limits on the critical point are estimated. Chemical freeze-out temperatures from the STAR and ALICE Collaborations will be compared to lines of constant physics calculated from the Taylor expansion of QCD bulk thermodynamic quantities. We show that qualitative features of the √{sNN} dependence of skewness and kurtosis ratios of net proton-number fluctuations measured by the STAR Collaboration can be understood from QCD results for cumulants of conserved baryon-number fluctuations. As an example for recent progress towards the determination of spectral and transport properties of the QGP from lattice QCD, we will present constraints on the thermal photon rate determined from a spectral reconstruction of continuum extrapolated lattice correlation functions in combination with input from most recent perturbative calculations.
International Nuclear Information System (INIS)
Dubovitskii, V.A.; Pavlov, G.A.; Krasnikov, Yu.G.
1996-01-01
Thermodynamic analysis of media with strong interparticle (Coulomb) interaction is presented. A method for constructing isotherms is proposed for a medium described by a closed multicomponent thermodynamic model. The method is based on choosing an appropriate nondegenerate frame of reference in the extended space of thermodynamic variables and provides efficient thermodynamic calculations in a wide range of parameters, for an investigation of phase transitions of the first kind, and for determining both the number of phases and coexistence curves. A number of approximate thermodynamic models of hydrogen plasma are discussed. The approximation corresponding to the n5/2 law, in which the effects of particle attraction and repulsion are taken into account qualitatively, is studied. This approximation allows studies of thermodynamic properties of a substance for a wide range of parameters. In this approximation, for hydrogen at a constant temperature, various properties of the degree of ionization are revealed. In addition, the parameters of the second critical point are found under conditions corresponding to the Jovian interior
International Nuclear Information System (INIS)
Carruthers, P.; Thews, R.L.
1988-01-01
This paper contains progress information on the following topics in High Energy Physics: strong, electromagnetic, and weak interactions; aspects of quark-gluon models for hadronic interactions, decays, and structure; the dynamical generation of a mass gap and the role and truthfulness of perturbation theory; statistical and dynamical aspects of hadronic multiparticle production; and realization of chiral symmetry and temperature effects in supersymmetric theories
International Nuclear Information System (INIS)
Maxton, P.M.; Schaeffer, M.W.; Ohline, S.M.; Kim, W.; Venturo, V.A.; Felker, P.M.
1994-01-01
Theoretical and experimental results pertaining to the excitation of intermolecular vibrations in the Raman and vibronic spectra of aromatic-containing, weakly bound complexes and clusters are reported. The theoretical analysis of intermolecular Raman activity is based on the assumption that the polarizability tensor of a weakly bound species is given by the sum of the polarizability tensors of its constituent monomers. The analysis shows that the van der Waals bending fundamentals in aromatic--rare gas complexes may be expected to be strongly Raman active. More generally, it predicts strong Raman activity for intermolecular vibrations that involve the libration or internal rotation of monomer moieties having appreciable permanent polarizability anisotropies. The vibronic activity of intermolecular vibrations in aromatic-rare gas complexes is analyzed under the assumption that every vibronic band gains its strength from an aromatic-localized transition. It is found that intermolecular vibrational excitations can accompany aromatic-localized vibronic excitations by the usual Franck--Condon mechanism or by a mechanism dependent on the librational amplitude of the aromatic moiety during the course of the pertinent intermolecular vibration. The latter mechanism can impart appreciable intensity to bands that are forbidden by rigid-molecule symmetry selection rules. The applicability of such rules is therefore called into question. Finally, experimental spectra of intermolecular transitions, obtained by mass-selective, ionization-detected stimulated Raman spectroscopies, are reported for benzene--X (X=Ar, --Ar 2 , N 2 , HCl, CO 2 , and --fluorene), fluorobenzene--Ar and --Kr, aniline--Ar, and fluorene--Ar and --Ar 2 . The results support the conclusions of the theoretical analyses and provide further evidence for the value of Raman methods in characterizing intermolecular vibrational level structures
Sivalingam, Kantharuban; Krupicka, Martin; Auer, Alexander A.; Neese, Frank
2016-08-01
Multireference (MR) methods occupy an important class of approaches in quantum chemistry. In many instances, for example, in studying complex magnetic properties of transition metal complexes, they are actually the only physically satisfactory choice. In traditional MR approaches, single and double excitations are performed with respect to all reference configurations (or configuration state functions, CSFs), which leads to an explosive increase of computational cost for larger reference spaces. This can be avoided by the internal contraction scheme proposed by Meyer and Siegbahn, which effectively reduces the number of wavefunction parameters to their single-reference counterpart. The "fully internally contracted" scheme (FIC) is well known from the popular CASPT2 approach. An even shorter expansion of the wavefunction is possible with the "strong contraction" (SC) scheme proposed by Angeli and Malrieu in their NEVPT2 approach. Promising multireference configuration interaction formulations (MRCI) employing internal contraction and strong contraction have been reported by several authors. In this work, we report on the implementation of the FIC-MRCI and SC-MRCI methodologies, using a computer assisted implementation strategy. The methods are benchmarked against the traditional uncontracted MRCI approach for ground and excited states of small molecules (N2, O2, CO, CO+, OH, CH, and CN). For ground states, the comparison includes the "partially internally contracted" MRCI based on the Celani-Werner ansatz (PC-MRCI). For the three contraction schemes, the average errors range from 2% to 6% of the uncontracted MRCI correlation energies. Excitation energies are reproduced with ˜0.2 eV accuracy. In most cases, the agreement is better than 0.2 eV, even in cases with very large differential correlation contributions as exemplified for the d-d and ligand-to-metal charge transfer transitions of a Cu [NH 3 ] 4 2 + model complex. The benchmark is supplemented with the
Graham, Kenneth; Cabanetos, Clement; Jahnke, Justin P.; Idso, Matthew N.; El Labban, Abdulrahman; Ngongang Ndjawa, Guy Olivier; Heumueller, Thomas; Vandewal, Koen; Salleo, Alberto; Chmelka, Bradley F.; Amassian, Aram; Beaujuge, Pierre; McGehee, Michael D.
2014-01-01
The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b]dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) 13C{1H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems
Graham, Kenneth
2014-07-09
The performance of organic photovoltaic (OPV) material systems are hypothesized to depend strongly on the intermolecular arrangements at the donor:fullerene interfaces. A review of some of the most efficient polymers utilized in polymer:fullerene PV devices, combined with an analysis of reported polymer donor materials wherein the same conjugated backbone was used with varying alkyl substituents, supports this hypothesis. Specifically, the literature shows that higher-performing donor-acceptor type polymers generally have acceptor moieties that are sterically accessible for interactions with the fullerene derivative, whereas the corresponding donor moieties tend to have branched alkyl substituents that sterically hinder interactions with the fullerene. To further explore the idea that the most beneficial polymer:fullerene arrangement involves the fullerene docking with the acceptor moiety, a family of benzo[1,2-b:4,5-b]dithiophene-thieno[3,4-c]pyrrole-4,6-dione polymers (PBDTTPD derivatives) was synthesized and tested in a variety of PV device types with vastly different aggregation states of the polymer. In agreement with our hypothesis, the PBDTTPD derivative with a more sterically accessible acceptor moiety and a more sterically hindered donor moiety shows the highest performance in bulk-heterojunction, bilayer, and low-polymer concentration PV devices where fullerene derivatives serve as the electron-accepting materials. Furthermore, external quantum efficiency measurements of the charge-transfer state and solid-state two-dimensional (2D) 13C{1H} heteronuclear correlation (HETCOR) NMR analyses support that a specific polymer:fullerene arrangement is present for the highest performing PBDTTPD derivative, in which the fullerene is in closer proximity to the acceptor moiety of the polymer. This work demonstrates that the polymer:fullerene arrangement and resulting intermolecular interactions may be key factors in determining the performance of OPV material systems
The interaction between theory and experiment in charge density analysis
International Nuclear Information System (INIS)
Coppens, Phillip
2013-01-01
The field of x-ray charge density analysis has gradually morphed into an area benefiting from the strong interactions between theoreticians and experimentalists, leading to new concepts on chemical bonding and of intermolecular interactions in condensed phases. Some highlights of the developments culminating in the 2013 Aminoff Award are described in this paper. (comment)
Measuring Intermolecular Binding Energies by Laser Spectroscopy.
Knochenmuss, Richard; Maity, Surajit; Féraud, Géraldine; Leutwyler, Samuel
2017-02-22
The ground-state dissociation energy, D0(S0), of isolated intermolecular complexes in the gas phase is a fundamental measure of the interaction strength between the molecules. We have developed a three-laser, triply resonant pump-dump-probe technique to measure dissociation energies of jet-cooled M•S complexes, where M is an aromatic chromophore and S is a closed-shell 'solvent' molecule. Stimulated emission pumping (SEP) via the S0→S1 electronic transition is used to precisely 'warm' the complex by populating high vibrational levels v" of the S0 state. If the deposited energy E(v") is less than D0(S0), the complex remains intact, and is then mass- and isomer-selectively detected by resonant two-photon ionization (R2PI) with a third (probe) laser. If the pumped level is above D0(S0), the hot complex dissociates and the probe signal disappears. Combining the fluorescence or SEP spectrum of the cold complex with the SEP breakoff of the hot complex brackets D0(S0). The UV chromophores 1-naphthol and carbazole were employed; these bind either dispersively via the aromatic rings, or form a hydrogen bond via the -OH or -NH group. Dissociation energies have been measured for dispersively bound complexes with noble gases (Ne, Kr, Ar, Xe), diatomics (N2, CO), alkanes (methane to n-butane), cycloalkanes (cyclopropane to cycloheptane), and unsaturated compounds (ethene, benzene). Hydrogen-bond dissociation energies have been measured for H2O, D2O, methanol, ethanol, ethers (oxirane, oxetane), NH3 and ND3.
Coupling of tt̄ and γγ with a strongly interacting Electroweak Symmetry Breaking Sector
Directory of Open Access Journals (Sweden)
Delgado Rafael L.
2017-01-01
Full Text Available We report the coupling of an external γγ or tt̄ state to a strongly interacting EWSBS satisfying unitarity. We exploit perturbation theory for those coupling of the external state, whereas the EWSBS is taken as strongly interacting. We use a modified version of the IAM unitarization procedure to model such a strongly interacting regime. The matrix elements VLVL → VLVL, VLVL ↔ hh, hh → hh, VLVL ↔ {γγ, tt̄}, hh ↔ {γγ, tt̄} are all computed to NLO in perturbation theory with the Nonlinear Effective Field Theory of the EWSBS, within the Equivalence Theorem. This allows us to describe resonances of the electroweak sector that may be found at the LHC and their effect on other channels such as γγ or tt̄ where they may be discovered.
Energy Technology Data Exchange (ETDEWEB)
Chan, J.; DePorcel, L.; Dixon, L. [eds.
1997-06-01
This conference explored the role of the strong interaction in the physics of hadrons and partons. The Institute attracted 239 physicists from 16 countries to hear lectures on the underlying theory of Quantum Chromodynamics, modern theoretical calculational techniques, and experimental investigation of the strong interaction as it appears in various phenomena. Different regimes in which one can calculate reliably in QCD were addressed in series of lectures on perturbation theory, lattice gauge theories, and heavy quark expansions. Studies of QCD in hadron-hadron collisions, electron-positron annihilation, and electron-proton collisions all give differing perspectives on the strong interaction--from low-x to high-Q{sup 2}. Experimental understanding of the production and decay of heavy quarks as well as the lighter meson states has continued to evolve over the past years, and these topics were also covered at the School. Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.
Pan, Xiaoyong; Wang, Weizhi; Ke, Lin; Zhang, Nan
2017-07-20
In this report, we showed the existence of RET induced intermolecular pairing force by comparing their fluorescence behaviors under room illumination vs standing in dark area for either PFluAnt solution or PFluAnt&PFOBT mixture. Their prominent emission attenuation under room illumination brought out the critical role of photo, i.e. RET induced intermolecular pairing force in induction of polymer aggregation. Constant UV-Vis absorption and fluorescence spectra in terms of both peak shapes and maximum wavelengths implied no chemical decomposition was involved. Recoverable fluorescence intensity, fluorescence lifetime as well as NMR spectra further exclude photo induced decomposition. The controllable on/off state of RET induced intermolecular pairing force was verified by the masking effect of outside PFluAnt solution which function as filter to block the excitation of inside PFluAnt and thus off the RET induced intermolecular pairing force. Theoretical calculation suggest that magnitude of RET induced intermolecular pairing force is on the same scale as that of van der Waals interaction. Although the absolute magnitude of RET induced intermolecular pairing force was not tunable, its effect can be magnified by intentionally turn it "on", which was achieved by irradiance with 5 W desk lamp in this report.
International Nuclear Information System (INIS)
Boreham, B. W.; Hora, H.
1997-01-01
We have recently developed a correspondence principle for electromagnetic interaction. When applied to laser interactions with electrons this correspondence principle identifies a critical laser intensity I*. This critical intensity is a transition intensity separating classical mechanical and quantum mechanical interaction regimes. In this paper we discuss the further application of I* to the interaction of bound electrons in atoms. By comparing I* with the ionisation threshold intensities as calculated from a cycle-averaged simple-atom model we conclude that I* can be usefully interpreted as a lower bound to the classical regime in studies of ionisation of gas atoms by intense laser beams
International Nuclear Information System (INIS)
Konijn, J.; Panman, J.K.; Koch, J.H.; Doesburg, W. van; Ewan, G.T.; Johansson, T.; Tibell, G.; Fransson, K.; Tauscher, L.
1979-01-01
Owing to a powerful Compton-suppression technique it was possible to observe for the first time the pionic 4f→3d X-ray transition in elements heavier than A=150. The strong interaction monopole shifts epsilon 0 and widths GAMMA 0 as well as the quadrupole splitting of the 3d levels have been measured in Ta, Re and Bi. Thus in addition to the strongly shifted and broadened 5g→4f transitions, a second, strongly affected line is available for these elements. For the pionic 4f levels, standard optical potentials fit the strong interaction shifts and broadenings quite well. The now observed, deeper-lying 3d states in Ta, Re and Bi have shifts and widths that differ by a factor of 2 or more from the standard optical potential predictions. From the observed relative X-ray intensities of the pionic cascade the strong interaction widths of the 5g and 4f levels are also extracted. (Auth.)
Pafong, E.; Geske, J.; Drossel, B.
2016-09-01
We study the wetting properties of water on silica surfaces using molecular dynamics (MD) simulations. To describe the intermolecular interaction between water and silica atoms, two types of interaction potential models are used: the standard BródkA and Zerda (BZ) model and the Gulmen and Thompson (GT) model. We perform an in-depth analysis of the influence of the choice of the potential on the arrangement of the water molecules in partially filled pores and on top of silica slabs. We find that at moderate pore filling ratios, the GT silica surface is completely wetted by water molecules, which agrees well with experimental findings, while the commonly used BZ surface is less hydrophilic and is only partially wetted. We interpret our simulation results using an analytical calculation of the phase diagram of water in partially filled pores. Moreover, an evaluation of the contact angle of the water droplet on top of the silica slab reveals that the interaction becomes more hydrophilic with increasing slab thickness and saturates around 2.5-3 nm, in agreement with the experimentally found value. Our analysis also shows that the hydroaffinity of the surface is mainly determined by the electrostatic interaction, but the van der Waals interaction nevertheless is strong enough that it can turn a hydrophobic surface into a hydrophilic surface.
DEFF Research Database (Denmark)
Hansen, Flemming Yssing; Alldredge, G. P.; Bruch, L. W.
1985-01-01
and gives a repulsive rather than an attractive electrostatic interaction at typical intermolecular distances. In the local multipole model, the atom-site dipoles give the largest contribution to both the molecular quadrupole moment and the intermolecular interaction. The Journal of Chemical Physics...
The Quantum-to-Classical Transition in Strongly Interacting Nanoscale Systems
Benatov, Latchezar Latchezarov
This thesis comprises two separate but related studies, dealing with two strongly interacting nanoscale systems on the border between the quantum and classical domains. In Part 1, we use a Born-Markov approximated master equation approach to study the symmetrized-in-frequency current noise spectrum and the oscillator steady state of a nanoelectromechanical system where a nanoscale resonator is coupled linearly via its momentum to a quantum point contact (QPC). Our current noise spectra exhibit clear signatures of the quantum correlations between the QPC current and the back-action force on the oscillator at a value of the relative tunneling phase where such correlations are expected to be maximized. We also show that the steady state of the oscillator obeys a classical Fokker-Planck equation, but can experience thermomechanical noise squeezing in the presence of a momentum-coupled detector bath and a position-coupled environmental bath. Besides, the full master equation clearly shows that half of the detector back-action is correlated with electron tunneling, indicating a departure from the model of the detector as an effective bath and suggesting that a future calculation valid at lower bias voltage, stronger tunneling and/or stronger coupling might reveal interesting quantum effects in the oscillator dynamics. In the second part of the thesis, we study the subsystem dynamics and thermalization of an oscillator-spin star model, where a nanomechanical resonator is coupled to a few two-level systems (TLS's). We use a fourth-order Runge-Kutta numerical algorithm to integrate the Schrodinger equation for the system and obtain our results. We find that the oscillator reaches a Boltzmann steady state when the TLS bath is initially in a thermal state at a temperature higher than the oscillator phonon energy. This occurs in both chaotic and integrable systems, and despite the small number of spins (only six) and the lack of couplings between them. At the same time, pure
International Nuclear Information System (INIS)
Zaikin, Yu.A.; Koztaeva, U.P.
2002-01-01
In earlier papers the internal friction (IF) method was applied to studies of structural relaxation in different types of polymer-based composite materials (glass-cloth, paper-based and foiled laminates impregnated by epoxy and phenolic resins) irradiated by 2 MeV electrons in the dose range of 0.1-50.0 MGy. Selectivity and high sensibility of the internal friction method allowed to distinguish glassy transitions in different structural components of the composites. The relaxation processes observed were identified and attributed to structural alterations in the polymer filler, the binder and the boundary layers. It was shown that changes in the parameters of relaxation maximums during irradiation can be considered as quantitative characteristics for the degree of radiation-induced degradation or cross-linking of polymer molecules. This paper deals with specific features of IF spectra in paper-based laminates where both the filler fibers and the binder are strongly interacting polymers. Anisotropy of viscous and elastic properties is very weak for this kind of materials, so that IF measurements give nearly the same result independently on the filler fiber orientation in the sample. The main reasons for it are the rigid chain structure of fillers (polyethylene-terephthalate and cellulose) and the good adhesion strengthened by diffusion of the epoxy or phenolic binder to defect regions of the filler.The IF temperature dependence observed in paper-based laminates is represented by superposition of two very broad relaxation maximums associated with transitions from glassy to high-elastic state in structural components, each based on one of the polymers. The inflection points characteristic for IF temperature dependence in paper-based laminates give a reason to treat them as a superposition of α-peaks associated with transitions from glassy to high-elastic state in structural components of a composite based on the binder and the filler, respectively. Another
Symmetry in the polarization expansion for intermolecular forces
International Nuclear Information System (INIS)
Chipman, D.M.; Hirschfelder, J.O.
1980-01-01
In the usual polarization expansion for intermolecular forces, exchange effects that determine the separations of energy levels within the manifold of interacting states are ignored. Previous low order calculations on simple physical systems have indicated that these exchange terms can be described reasonably well by an appropriate ad hoc symmetrization of the polarization wave function (the SYM-P method). But theoretical considerations suggest that the SYM-P method should be good for only one of the interacting states and not for the others in the manifold. Here this long standing apparent conflict between theoretical expectations and actual results is explained by consideration of a simple model system in which the relevant equations can be solved exactly. It is concluded that while the SYM-P method is potentially exact for only one of the interacting states, it may provide good approximations to the other states of the manifold in the case of large separations of the interacting subsystems
Cohesion: a scientific history of intermolecular forces
National Research Council Canada - National Science Library
Rowlinson, J. S
2002-01-01
.... The ﬁnal section gives an account of the successful use in the 20th century of quantum mechanics and statistical mechanics to resolve most of the remaining problems. Throughout the last 300 years there have been periods of tremendous growth in our understanding of intermolecular forces but such interest proved to be unsustainable, and long periods of...
International Nuclear Information System (INIS)
Zhou, Yongxi; Ernzerhof, Matthias; Bahmann, Hilke
2015-01-01
Drawing on the adiabatic connection of density functional theory, exchange-correlation functionals of Kohn-Sham density functional theory are constructed which interpolate between the extreme limits of the electron-electron interaction strength. The first limit is the non-interacting one, where there is only exchange. The second limit is the strong correlated one, characterized as the minimum of the electron-electron repulsion energy. The exchange-correlation energy in the strong-correlation limit is approximated through a model for the exchange-correlation hole that is referred to as nonlocal-radius model [L. O. Wagner and P. Gori-Giorgi, Phys. Rev. A 90, 052512 (2014)]. Using the non-interacting and strong-correlated extremes, various interpolation schemes are presented that yield new approximations to the adiabatic connection and thus to the exchange-correlation energy. Some of them rely on empiricism while others do not. Several of the proposed approximations yield the exact exchange-correlation energy for one-electron systems where local and semi-local approximations often fail badly. Other proposed approximations generalize existing global hybrids by using a fraction of the exchange-correlation energy in the strong-correlation limit to replace an equal fraction of the semi-local approximation to the exchange-correlation energy in the strong-correlation limit. The performance of the proposed approximations is evaluated for molecular atomization energies, total atomic energies, and ionization potentials
International Nuclear Information System (INIS)
Benisti, D.
2011-01-01
This manuscript provides a theoretical description, sometimes illustrated by experimental results, of several examples of field-matter interaction in various domains of physics, showing how the same basic concepts and theoretical methods may be used in very different physics situations. The issues addressed here are nonlinear field-matter interaction in plasma physics within the framework of classical mechanics (with a particular emphasis on wave-particle interaction), the linear analysis of beam-plasma instabilities in the relativistic regime, and the quantum description of laser-atom interaction, including quantum electrodynamics. Novel methods are systematically introduced in order to solve some very old problems, like the nonlinear counterpart of the Landau damping rate in plasma physics, for example. Moreover, our results directly apply to inertial confinement fusion, laser propagation in an atomic vapor, ion acceleration in a magnetized plasma and the physics of the Reversed Field Pinch for magnetic fusion. (author)
Evidence for a strong sulfur-aromatic interaction derived from crystallographic data.
Zauhar, R J; Colbert, C L; Morgan, R S; Welsh, W J
2000-03-01
We have uncovered new evidence for a significant interaction between divalent sulfur atoms and aromatic rings. Our study involves a statistical analysis of interatomic distances and other geometric descriptors derived from entries in the Cambridge Crystallographic Database (F. H. Allen and O. Kennard, Chem. Design Auto. News, 1993, Vol. 8, pp. 1 and 31-37). A set of descriptors was defined sufficient in number and type so as to elucidate completely the preferred geometry of interaction between six-membered aromatic carbon rings and divalent sulfurs for all crystal structures of nonmetal-bearing organic compounds present in the database. In order to test statistical significance, analogous probability distributions for the interaction of the moiety X-CH(2)-X with aromatic rings were computed, and taken a priori to correspond to the null hypothesis of no significant interaction. Tests of significance were carried our pairwise between probability distributions of sulfur-aromatic interaction descriptors and their CH(2)-aromatic analogues using the Smirnov-Kolmogorov nonparametric test (W. W. Daniel, Applied Nonparametric Statistics, Houghton-Mifflin: Boston, New York, 1978, pp. 276-286), and in all cases significance at the 99% confidence level or better was observed. Local maxima of the probability distributions were used to define a preferred geometry of interaction between the divalent sulfur moiety and the aromatic ring. Molecular mechanics studies were performed in an effort to better understand the physical basis of the interaction. This study confirms observations based on statistics of interaction of amino acids in protein crystal structures (R. S. Morgan, C. E. Tatsch, R. H. Gushard, J. M. McAdon, and P. K. Warme, International Journal of Peptide Protein Research, 1978, Vol. 11, pp. 209-217; R. S. Morgan and J. M. McAdon, International Journal of Peptide Protein Research, 1980, Vol. 15, pp. 177-180; K. S. C. Reid, P. F. Lindley, and J. M. Thornton, FEBS
International Nuclear Information System (INIS)
Zhang Zhaoxi
2005-01-01
The 2004 Nobel Prize in Physics was awarded to David J. Gross, Frank Wilczek and H. David Politzer for their decisive contributions to the theory of the asymptotic freedom of the strong interaction (a fundamental interaction). The fundamental elements of quantum chromodynamics (QCD) and the theory of the strong interaction are briefly reviewed in their historical context. How to achieve asymptotic freedom is introduced and its physical meaning explained. The latest experimental tests of asymptotic freedom are presented, and it is shown that the theoretical prediction agrees excellently with the experimental measurements. Perturbative QCD which is based on the asymptotic freedom is outlined. It is pointed out that the theoretical discovery and experimental proof of the asymptotic freedom are crucial for QCD to be the correct theory of strong interaction. Certain frontier research areas of QCD, such as 'color confinement', are mentioned. The discovery and confirmation of asymptotic freedom has indeed deeply affected particle physics, and has led to QCD becoming a main content of the standard model, and to further development of the so-called grand unification theories of interactions. (author)
Systematics of interaction and strong absorption radii determined from heavy-ion elastic scattering
International Nuclear Information System (INIS)
Birkelund, J.R.; Huizenga, J.R.
1977-01-01
Various methods for determining the strong absorption radius for light and intermediate mass nuclei are discussed. It is found that this determination in terms of the half-density radii of the target and projectile is more accurate over the whole range of available data than the other simple parametrizations. 62 references
Veljković, Dušan Ž
2018-03-01
Energies of CH/O interactions between water molecule and polycyclic aromatic hydrocarbons with a different number of aromatic rings were calculated using ab initio calculations at MP2/cc-PVTZ level. Results show that an additional aromatic ring in structure of polycyclic aromatic hydrocarbons significantly strengthens CH/O interactions. Calculated interaction energies in optimized structures of the most stable tetracene/water complex is -2.27 kcal/mol, anthracene/water is -2.13 kcal/mol and naphthalene/water is -1.97 kcal/mol. These interactions are stronger than CH/O contacts in benzene/water complex (-1.44 kcal/mol) while CH/O contacts in tetracene/water complex are even stronger than CH/O contacts in pyridine/water complexes (-2.21 kcal/mol). Electrostatic potential maps for different polycyclic aromatic hydrocarbons were calculated and used to explain trends in the energies of interactions. Copyright © 2017 Elsevier Inc. All rights reserved.
A model-independent description of few-body system with strong interaction
International Nuclear Information System (INIS)
Simenog, I.V.
1985-01-01
In this contribution, the authors discuss the formulation of equations that provide model-independent description of systems of three and more nucleons irrespective of the details of the interaction, substantiate the approach, estimate the correction terms with respect to the force range, and give basic qualitative results obtained by means of the model-independent procedure. They consider three nucleons in the doublet state (spin S=I/2) taking into account only S-interaction. The elastic nd-scattering amplitude may be found from the model-independent equations that follow from the Faddeev equations in the short-range-force limit. They note that the solutions of several model-independent equations and basic results obtained with the use of this approach may serve both as a standard solution and starting point in the discussion of various conceptions concerning the details of nuclear interactions
Motion of Rydberg atoms with strong permanent-electric-dipole interactions
International Nuclear Information System (INIS)
Gonçalves, Luís Felipe; Thaicharoen, Nithiwadee; Raithel, Georg
2016-01-01
Using classical trajectories simulations, we investigate the dynamics of a cold sample of Rydberg atoms with high permanent electric dipole moments. The dipolar state can be created using an adiabatic passage through an avoided crossing between an S-like state and a linear Stark state. The simulations yield the pair-correlation functions (PCF) of the atom samples, which allow us to extract the motion of Rydberg-atom pairs in the many-body system. The results reveal the strength and the anisotropic character of the underlying interaction. The simulation is employed to test the suitability of experimental methods designed to derive interaction parameters from PCF. Insight is obtained about the stability of the method against variation of experimentally relevant parameters. Transient correlations due to interaction-induced heating are observed. (paper)
Karakostas, Vassilios; Papadimitriou, Eleftheria; Jin, Xueshen; Liu, Zhihui; Paradisopoulou, Parthena; He, Zhang
2013-10-01
Northeast China, a densely populated area, is affected by intense seismic activity, which includes large events that caused extensive disaster and tremendous loss of life. For contributing to the continuous efforts for seismic hazard assessment, the earthquake potential from the active faults near the cities of Zhangjiakou and Langfang in Hebei Province is examined. We estimate the effect of the coseismic stress changes of strong (M ⩾ 5.0) earthquakes on the major regional active faults, and mapped Coulomb stress change onto these target faults. More importantly our calculations reveal that positive stress changes caused by the largest events of the 1976 Tangshan sequence make the Xiadian and part of Daxing fault, thus considered the most likely sites of the next strong earthquake in the study area. The accumulated static stress changes that reached a value of up to 0.4 bar onto these faults, were subsequently incorporated in earthquake probability estimates for the next 30 years.
RAMAN LIGHT SCATTERING IN PSEUDOSPIN-ELECTRON MODEL AT STRONG PSEUDOSPIN-ELECTRON INTERACTION
Directory of Open Access Journals (Sweden)
T.S.Mysakovych
2004-01-01
Full Text Available Anharmonic phonon contributions to Raman scattering in locally anharmonic crystal systems in the framework of the pseudospin-electron model with tunneling splitting of levels are investigated. The case of strong pseudospin-electron coupling is considered. Pseudospin and electron contributions to scattering are taken into account. Frequency dependences of Raman scattering intensity for different values of model parameters and for different polarization of scattering and incident light are investigated.
Spectral asymptotics of a strong delta ' interaction on a planar loop
Czech Academy of Sciences Publication Activity Database
Exner, Pavel; Jex, M.
2013-01-01
Roč. 46, č. 34 (2013), s. 345201 ISSN 1751-8113 R&D Projects: GA ČR GAP203/11/0701 Institutional support: RVO:61389005 Keywords : Schrodinger operators * strong coupling asymptotics Subject RIV: BE - Theoretical Physics Impact factor: 1.687, year: 2013 http://iopscience.iop.org/1751-8121/46/34/345201/pdf/1751-8121_46_34_345201.pdf
Periodicity and chaos in strongly perturbed classical orbitals for Coulomb interactions
Energy Technology Data Exchange (ETDEWEB)
Klar, H
1986-01-01
Within the framework of classical mechanics two prototypes of strongly perturbed orbitals, the diamagnetism in hydrogen and electronic double excitation, are analyzed near critical phase space points (fixed points). The motion of the hydrogen electron under the joint influence of the Coulomb field and the magnetic field is periodic for any field strengths. For a two-electron atom however the author finds a chaotic time evolution of the electron pair correlation, causing presumably irregular spectral patterns. (Auth.).
Energy Technology Data Exchange (ETDEWEB)
Fournier, Joseph A.; Wolke, Conrad T.; Johnson, Christopher J.; Johnson, Mark A., E-mail: mark.johnson@yale.edu, E-mail: mccoy@chemistry.ohio-state.edu [Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520 (United States); McCoy, Anne B., E-mail: mark.johnson@yale.edu, E-mail: mccoy@chemistry.ohio-state.edu [Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio 43210 (United States)
2015-02-14
We clarify the role of the critical imidazolium C{sub (2)}H position (the central C between N atoms in the heterocycle) in the assembly motif of the [EMIM][BF{sub 4}] ionic liquid by analyzing the vibrational spectra of the bare EMIM{sup +} ion as well as that of the cationic [EMIM]{sub 2}[BF{sub 4}]{sup +} (EMIM{sup +} = 1-ethyl-3-methylimidazolium, C{sub 6}H{sub 11}N{sub 2}{sup +}) cluster. Vibrational spectra of the cold, mass-selected ions are obtained using cryogenic ion vibrational predissociation of weakly bound D{sub 2} molecules formed in a 10 K ion trap. The C{sub (2)}H behavior is isolated by following the evolution of key vibrational features when the C{sub (2)} hydrogen, the proposed binding location of the anion to the imidazolium ring, is replaced by either deuterium or a methyl group (i.e., in the EMMIM{sup +} analogue). Strong features in the ring CH stretching region of the bare ion are traced to Fermi resonances with overtones of lower frequency modes. Upon incorporation into the EMIM{sup +} ⋅ ⋅ ⋅ BF{sub 4}{sup −} ⋅ ⋅ ⋅ EMIM{sup +} ternary complex, the C{sub (2)}H oscillator strength is dramatically increased, accounting for the much more complicated patterns derived from the EMIM{sup +} ring CH stretches in the light isotopomer, which are strongly suppressed in the deuterated analogue. Further changes in the spectra that occur when the C{sub (2)}H is replaced by a methyl group are consistent with BF{sub 4}{sup −} attachment directly to the imidazolium ring in an arrangement that maximizes the electrostatic interaction between the molecular ions.
Numerical investigation into strong axis bending shear interaction in rolled I-shaped steel sections
Dekker, R.W.A.; Snijder, B.H.; Maljaars, J.
2016-01-01
Clause 6.2.8 of EN 1993-1-1 covers the design rules on bending-shear resistance, taking presence of shear into account by a reduced yield stress for the shear area. Numerical research on bending-shear interaction by means of the Abaqus Finite Element modelling soft-ware is presented. The numerical
Numerical investigation into strong axis bending-shear interaction in rolled I-shaped steel sections
Dekker, R.W.A.; Snijder, H.H.; Maljaars, J.; Dubina, Dan; Ungureanu, Viorel
2016-01-01
Clause 6.2.8 of EN 1993-1-1 covers the design rules on bending-shear resistance, taking presence of shear into account by a reduced yield stress for the shear area. Numerical research on bending-shear interaction by means of the Abaqus Finite Element modelling software is presented. The numerical
Interaction of N-hydroxyurea with strong proton donors: HCl and HF
International Nuclear Information System (INIS)
Sałdyka, Magdalena
2014-01-01
Highlights: • 1:1 and 1:2 N-hydroxyurea complexes with HCl and HF are trapped in argon matrices. • The complexes are stabilized by strong X–H⋯O bond. • Hydrogen bonds in the cyclic 1:2 complexes show strong cooperativity. • The C=O group is the strongest proton acceptor centre in the N-hydroxyurea molecule. - Abstract: An infrared spectroscopic and MP2/6-311++G(2d,2p) study of strong hydrogen bonded complexes of N-hydroxyurea (NH 2 CONHOH) with hydrogen halides (HCl and HF) trapped in solid argon matrices is reported. 1:1 and 1:2 complexes between N-hydroxyurea and hydrogen chloride, hydrogen fluoride have been identified in the NH 2 CONHOH/HCl/Ar, NH 2 CONHOH/HF/Ar matrices, respectively; their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes, identified for both hydrogen halide molecules, the cyclic structure stabilized by the X–H⋯O and N–H⋯X bonds is present; for the NH 2 CONHOH⋯HF system another isomeric 1:1 complex is also observed. Two 1:2 complexes were identified for the N-hydroxyurea–hydrogen chloride system characterised by the Cl–H⋯O and N–H⋯Cl bonds. The results of the study evidence that N-hydroxyurea is an oxygen base in the gas-phase with the carbonyl group as the strongest proton acceptor centre in the molecule
Interaction of N-hydroxyurea with strong proton donors: HCl and HF
Energy Technology Data Exchange (ETDEWEB)
Sałdyka, Magdalena, E-mail: magdalena.saldyka@chem.uni.wroc.pl
2014-11-24
Highlights: • 1:1 and 1:2 N-hydroxyurea complexes with HCl and HF are trapped in argon matrices. • The complexes are stabilized by strong X–H⋯O bond. • Hydrogen bonds in the cyclic 1:2 complexes show strong cooperativity. • The C=O group is the strongest proton acceptor centre in the N-hydroxyurea molecule. - Abstract: An infrared spectroscopic and MP2/6-311++G(2d,2p) study of strong hydrogen bonded complexes of N-hydroxyurea (NH{sub 2}CONHOH) with hydrogen halides (HCl and HF) trapped in solid argon matrices is reported. 1:1 and 1:2 complexes between N-hydroxyurea and hydrogen chloride, hydrogen fluoride have been identified in the NH{sub 2}CONHOH/HCl/Ar, NH{sub 2}CONHOH/HF/Ar matrices, respectively; their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes, identified for both hydrogen halide molecules, the cyclic structure stabilized by the X–H⋯O and N–H⋯X bonds is present; for the NH{sub 2}CONHOH⋯HF system another isomeric 1:1 complex is also observed. Two 1:2 complexes were identified for the N-hydroxyurea–hydrogen chloride system characterised by the Cl–H⋯O and N–H⋯Cl bonds. The results of the study evidence that N-hydroxyurea is an oxygen base in the gas-phase with the carbonyl group as the strongest proton acceptor centre in the molecule.
Strong electron-phonon interaction in the high-Tc superconductors: Evidence from the infrared
International Nuclear Information System (INIS)
Timusk, T.; Porter, C.D.; Tanner, D.B.
1991-01-01
We show that low-frequency structure in the infrared reflectance of the high-temperature superconductor YBa 2 Cu 3 O 7 results from the electron-phonon interaction. Characteristic antiresonant line shapes are seen in the phonon region of the spectrum and the frequency-dependent scattering rate of the mid-infrared electronic continuum has peaks at 150 cm -1 (19 meV) and at 360 cm -1 (45 meV) in good agreement with phonon density-of-states peaks in neutron time-of-flight spectra that develop in superconducting samples. The interaction between the phonons and the charge carriers can be understood in terms of a charged-phonon model
DEFF Research Database (Denmark)
Dreiser, Jan; Wäckerlin, Christian; Ali, Md. Ehesan
2014-01-01
We present a comprehensive study of Er(trensal) single-ion magnets deposited in ultrahigh vacuum onto metallic surfaces. X-ray photoelectron spectroscopy reveals that the molecular structure is preserved after sublimation, and that the molecules are physisorbed on Au(111) while they are chemisorbed...... on a Ni thin film on Cu(100) single-crystalline surfaces. X-ray magnetic circular dichroism (XMCD) measurements performed on Au(111) samples covered with molecular monolayers held at temperatures down to 4 K suggest that the easy axes of the strongly anisotropic molecules are randomly oriented...... pathways toward optical addressing of surface-deposited single-ion magnets....
CLEO-c and CESR-c: A new frontier in strong and weak interactions
Energy Technology Data Exchange (ETDEWEB)
Richichi, Stephen J
2003-06-01
We report on the physics potential of a charm and QCD factory, based on a proposal for the conversion of the existing CESR machine and CLEO detector: ''CESR-c and OLEO-c''. Such a facility will make major contributions to the field of quark flavor physics in this decade. It may also provide the best chance for understanding non-perturbative QCD, which is essential to understanding the strongly-coupled sectors of the new physics that lies beyond the Standard Model.
CLEO-c and CESR-c: A new frontier in strong and weak interactions
Richichi, Stephen J.
2003-06-01
We report on the physics potential of a charm and QCD factory, based on a proposal for the conversion of the existing CESR machine and CLEO detector: "CESR-c and OLEO-c". Such a facility will make major contributions to the field of quark flavor physics in this decade. It may also provide the best chance for understanding non-perturbative QCD, which is essential to understanding the strongly-coupled sectors of the new physics that lies beyond the Standard Model.
CLEO-c and CESR-c: A new frontier in strong and weak interactions
International Nuclear Information System (INIS)
Richichi, Stephen J.
2003-01-01
We report on the physics potential of a charm and QCD factory, based on a proposal for the conversion of the existing CESR machine and CLEO detector: ''CESR-c and OLEO-c''. Such a facility will make major contributions to the field of quark flavor physics in this decade. It may also provide the best chance for understanding non-perturbative QCD, which is essential to understanding the strongly-coupled sectors of the new physics that lies beyond the Standard Model
Two-Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence
Che, H.
2014-01-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum tra...
Second sound in a two-dimensional Bose gas: From the weakly to the strongly interacting regime
Ota, Miki; Stringari, Sandro
2018-03-01
Using Landau's theory of two-fluid hydrodynamics, we investigate first and second sounds propagating in a two-dimensional (2D) Bose gas. We study the temperature and interaction dependence of both sound modes and show that their behavior exhibits a deep qualitative change as the gas evolves from the weakly interacting to the strongly interacting regime. Special emphasis is placed on the jump of both sounds at the Berezinskii-Kosterlitz-Thouless transition, caused by the discontinuity of the superfluid density. We find that the excitation of second sound through a density perturbation becomes weaker and weaker as the interaction strength increases as a consequence of the decrease in the thermal expansion coefficient. Our results could be relevant for future experiments on the propagation of sound on the Bose-Einstein condensate (BEC) side of the BCS-BEC crossover of a 2D superfluid Fermi gas.
Energy Technology Data Exchange (ETDEWEB)
Quinn, John
2009-11-30
Work related to this project introduced the idea of an effective monopole strength Q* that acted as the effective angular momentum of the lowest shell of composite Fermions (CF). This allowed us to predict the angular momentum of the lowest band of energy states for any value of the applied magnetic field simply by determining N{sub QP} the number of quasielectrons (QE) or quasiholes (QH) in a partially filled CF shell and adding angular momenta of the N{sub QP} Fermions excitations. The approach reported treated the filled CF level as a vacuum state which could support QE and QH excitations. Numerical diagonalization of small systems allowed us to determine the angular momenta, the energy, and the pair interaction energies of these elementary excitations. The spectra of low energy states could then be evaluated in a Fermi liquid-like picture, treating the much smaller number of quasiparticles and their interactions instead of the larger system of N electrons with Coulomb interactions.
Aspects of the flipped unification of strong, weak and electromagnetic interactions
Energy Technology Data Exchange (ETDEWEB)
Ellis, J.; Hagelin, J.S.; Kelley, S.; Nanopoulos, D.V.
1988-12-19
We explore phenomenological aspects of a recently proposed flipped SU(5) x U(1) supersymmetric GUT which incorporates an economical and natural mechanism for splitting Higgs doublets and triplets, and can be derived from string theory. Using experimental values of sin/sup 2/theta/sub W/ and the strong QCD coupling, we estimate the grand unification scale M/sub G/, where the strong and weak coupling strengths are equal, and the superunification scale M/sub SU/, where all couplings are equal. We find typical values of M/sub G/ approx. = 10/sup 15/ to 10/sup 17/ GeV, with M/sub SU/ somewhat higher and close to the value suggested by string models. We discuss different mechanisms for baryon decay, finding that the dominant one is gauge-boson exchange giving rise to p -> e/sup +/ /sup 0/, anti /sup +/ and n -> e/sup +/ /sup -/, anti /sup 0/ with partial lifetimes approx. = 10/sup 35+-2/ y. We show that a large GUT symmetry-breaking scale M/sub G/ is naturally generated by radiative corrections to the effective potential if a small amount approx. = m/sub W/ of soft supersymmetry breaking is generated dynamically at a large scale. We analyze the low-energy effective theory obtained using the renormalization group equations, demonstrating that electroweak symmetry breaking is obtained if m/sub t/ approx. = 60 to 90 GeV. We analyze the spectrum of sparticles, with particular attention to neutralinos.
Bozeman, Trevor C; Nanjunda, Rupesh; Tang, Chenhong; Liu, Yang; Segerman, Zachary J; Zaleski, Paul A; Wilson, W David; Hecht, Sidney M
2012-10-31
Recent studies involving DNAs bound strongly by bleomycins have documented that such DNAs are degraded by the antitumor antibiotic with characteristics different from those observed when studying the cleavage of randomly chosen DNAs in the presence of excess Fe·BLM. In the present study, surface plasmon resonance has been used to characterize the dynamics of BLM B(2) binding to a strongly bound hairpin DNA, to define the effects of Fe(3+), salt, and temperature on BLM-DNA interaction. One strong primary DNA binding site, and at least one much weaker site, were documented. In contrast, more than one strong cleavage site was found, an observation also made for two other hairpin DNAs. Evidence is presented for BLM equilibration between the stronger and weaker binding sites in a way that renders BLM unavailable to other, less strongly bound DNAs. Thus, enhanced binding to a given site does not necessarily result in increased DNA degradation at that site; i.e., for strongly bound DNAs, the facility of DNA cleavage must involve other parameters in addition to the intrinsic rate of C-4' H atom abstraction from DNA sugars.
Digital communication through intermolecular fluorescence modulation.
Raymo, F M; Giordani, S
2001-06-14
[see reaction]. Ultraminiaturized processors incorporating molecular components can be developed only after devising efficient strategies to communicate signals at the molecular level. We have demonstrated that a three-state molecular switch responds to ultraviolet light, visible light, and H+, attenuating the emission intensity of a fluorescent probe. Intermolecular communication is responsible for the transduction of three input signals into a single optical output. The behavior of the communicating ensemble of molecules corresponds to that of a logic circuit incorporating seven gates.
Metastability and avalanche dynamics in strongly correlated gases with long-range interactions
Hruby, Lorenz; Dogra, Nishant; Landini, Manuele; Donner, Tobias; Esslinger, Tilman
2018-03-01
We experimentally study the stability of a bosonic Mott insulator against the formation of a density wave induced by long-range interactions and characterize the intrinsic dynamics between these two states. The Mott insulator is created in a quantum degenerate gas of 87-Rubidium atoms, trapped in a 3D optical lattice. The gas is located inside and globally coupled to an optical cavity. This causes interactions of global range, mediated by photons dispersively scattered between a transverse lattice and the cavity. The scattering comes with an atomic density modulation, which is measured by the photon flux leaking from the cavity. We initialize the system in a Mott-insulating state and then rapidly increase the global coupling strength. We observe that the system falls into either of two distinct final states. One is characterized by a low photon flux, signaling a Mott insulator, and the other is characterized by a high photon flux, which we associate with a density wave. Ramping the global coupling slowly, we observe a hysteresis loop between the two states—a further signature of metastability. A comparison with a theoretical model confirms that the metastability originates in the competition between short- and global-range interactions. From the increasing photon flux monitored during the switching process, we find that several thousand atoms tunnel to a neighboring site on the timescale of the single-particle dynamics. We argue that a density modulation, initially forming in the compressible surface of the trapped gas, triggers an avalanche tunneling process in the Mott-insulating region.
Gravity as a dynamical consequence of the strong, weak, and electromagnetic interactions
International Nuclear Information System (INIS)
Zee, A.
1981-12-01
A coherent and reasonable account of gravitational physics is shown to be possible. The three non-gravitational interactions are described by a scale and conformal invariant and asymptotically free Yang-Mills theory with massless fermions. Conformal invariance is required so that the gravitational sector of the theory is given by the Weyl action. The theory is renormalizable and has a unitary S-matrix. Possible breakdown of causality is observable only at the Planck length. In this theory, Einstein's theory of gravity is induced as an effective long-distance theory. An R 2 term is also induced with a finite and physically desired sign
Probing non nucleonic degrees of freedom with strong and electromagnetic interactions
International Nuclear Information System (INIS)
Frois, B.
1985-10-01
In this talk, I would like to examine our present view on non-nucleonic degrees of freedom with a few typical experimental results obtained recently both with hadronic and electromagnetic probes at intermediate energies. It is the first generation of experimental data which has probed mesonic degrees of freedom with a spatial resolution of the order of 0.5 fm. This has made possible for example the measurement of the size of the pion-nucleon interaction region. This is very stimulating progress and we begin to have a coherent overview on the various reaction mechanisms which are induced by hadronic and electromagnetic probes
International Nuclear Information System (INIS)
Yu Zengqiang; Zhai Hui; Zhang Shizhong
2011-01-01
We study the properties of dilute bosons immersed in a single-component Fermi sea across a broad boson-fermion Feshbach resonance. The stability of the mixture requires that the bare interaction between bosons exceeds a critical value, which is a universal function of the boson-fermion scattering length, and exhibits a maximum in the unitary region. We calculate the quantum depletion, momentum distribution, and the boson contact parameter across the resonance. The transition from condensate to molecular Fermi gas is also discussed.
Energy Technology Data Exchange (ETDEWEB)
Schriber, Jeffrey B.; Evangelista, Francesco A. [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States)
2016-04-28
We introduce a new procedure for iterative selection of determinant spaces capable of describing highly correlated systems. This adaptive configuration interaction (ACI) determines an optimal basis by an iterative procedure in which the determinant space is expanded and coarse grained until self-consistency. Two importance criteria control the selection process and tune the ACI to a user-defined level of accuracy. The ACI is shown to yield potential energy curves of N{sub 2} with nearly constant errors, and it predicts singlet-triplet splittings of acenes up to decacene that are in good agreement with the density matrix renormalization group.
Energy Technology Data Exchange (ETDEWEB)
Daily, Michael D.; Baer, Marcel D.; Mundy, Christopher J.
2016-03-10
The description of peptides and the use of molecular dynamics simulations to refine structures and investigate the dynamics on an atomistic scale are well developed. Through a consensus in this community over multiple decades, parameters were developed for molecular interactions that only require the sequence of amino-acids and an initial guess for the three-dimensional structure. The recent discovery of peptoids will require a retooling of the currently available interaction potentials in order to have the same level of confidence in the predicted structures and pathways as there is presently in the peptide counterparts. Here we present modeling of peptoids using a combination of ab initio molecular dynamics (AIMD) and atomistic resolution classical forcefield (FF) to span the relevant time and length scales. To properly account for the dominant forces that stabilize ordered structures of peptoids, namely steric-, electrostatic, and hydrophobic interactions mediated through sidechain-sidechain interactions in the FF model, those have to be first mapped out using high fidelity atomistic representations. A key feature here is not only to use gas phase quantum chemistry tools, but also account for solvation effects in the condensed phase through AIMD. One major challenge is to elucidate ion binding to charged or polar regions of the peptoid and its concomitant role in the creation of local order. Here, similar to proteins, a specific ion effect is observed suggesting that both the net charge and the precise chemical nature of the ion will need to be described. MDD was supported by MS3 (Materials Synthesis and Simulation Across Scales) Initiative at Pacific Northwest National Laboratory. Research was funded by the Laboratory Directed Research and Development program at Pacific Northwest National Laboratory. MDB acknowledges support from US Department of Energy, Office of Science, Office of Basic Energy Sciences, Division of Material & Engineering. CJM acknowledges
Wan, Sijie; Peng, Jingsong; Li, Yuchen; Hu, Han; Jiang, Lei; Cheng, Qunfeng
2015-10-27
Graphene is the strongest and stiffest material, leading to the development of promising applications in many fields. However, the assembly of graphene nanosheets into macrosized nanocomposites for practical applications remains a challenge. Nacre in its natural form sets the "gold standard" for toughness and strength, which serves as a guide to the assembly of graphene nanosheets into high-performance nanocomposites. Here we show the strong, tough, conductive artificial nacre based on graphene oxide through synergistic interactions of hydrogen and covalent bonding. Tensile strength and toughness was 4 and 10 times higher, respectively, than that of natural nacre. The exceptional integrated strong and tough artificial nacre has promising applications in aerospace, artificial muscle, and tissue engineering, especially for flexible supercapacitor electrodes due to its high electrical conductivity. The use of synergistic interactions is a strategy for the development of high-performance nanocomposites.
Rewetting phenomena and their relation to intermolecular forces between a hot wall and the fluid
International Nuclear Information System (INIS)
Gerweck, V.
1989-12-01
The rewetting phenomena and the different physical concepts which are used in their modelisation are reviewed. The present work studies the effect of the intermolecular forces between the hot wall and the fluid on this phase transition. Using suitable approximations, a local equation of state is obtained by the treatment of the fluid-fluid and fluid-wall intermolecular interactions. This local equation of state depends on the distance from the wall, and the critical pressure and temperature become a function of the distance from the wall, whereas the critical density is left constant throughout the fluid. At the wall, the critical pressure and temperature are half their bulk values and increase towards the bulk value as the distance from the wall increases. The penetration of a temperature profile in this fluid is studied by assuming that the liquid density is not strongly affected by this temperature profile as long as there is no phase transition. It is shown that the phase transition will occur extremely rapidly when the interfacial temperature upon contact is higher than the minimum of the local spinodal temperature, which varies with the distance from the wall. The result ist cast in the form of an interfacial rewetting temperature fT c above which rewetting of the surface by liquid-wall contacts is not expected because these contacts will be terminated in extremely short times. Comparing the theory with available data shows that in the usual rewetting situations the theory reduces to the use of the bulk spinodal temperature. For surfaces coated with poorly wetted materials the correction factor due to surface effects applies, reducing the rewetting temperature, in agreement with the experimental data. For liquid metals it appears that the theory is applied in a region where the basic theoretical approximations are very coarse; but even in that case the experimental trend is qualitatively predicted by the theory. (author) 43 figs., 11 tabs., 105 refs
Equilibration of a strongly interacting plasma: holographic analysis of local and nonlocal probes
Directory of Open Access Journals (Sweden)
Bellantuono Loredana
2016-01-01
Full Text Available The relaxation of a strongly coupled plasma towards the hydrodynamic regime is studied by analyzing the evolution of local and nonlocal observables in the holographic approach. The system is driven in an initial anisotropic and far-from equilibrium state through an impulsive time-dependent deformation (quench of the boundary spacetime geometry. Effective temperature and entropy density are related to the position and area of a black hole horizon, which has formed as a consequence of the distortion. The behavior of stress-energy tensor, equal-time correlation functions and Wilson loops of different shapes is examined, and a hierarchy among their thermalization times emerges: probes involving shorter length scales thermalize faster.
Nonlinear interaction of charged particles with strong laser pulses in a gaseous media
Directory of Open Access Journals (Sweden)
H. K. Avetissian
2007-07-01
Full Text Available The charged particles nonlinear dynamics in the field of a strong electromagnetic wave pulse of finite duration and certain form of the envelope, in the refractive medium with a constant and variable refraction indexes, is investigated by means of numerical integration of the classical relativistic equations of motion. The particle energy dependence on the pulse intensity manifests the nonlinear threshold phenomenon of a particle reflection and capture by actual laser pulses in dielectric-gaseous media that takes place for a plane electromagnetic wave in the induced Cherenkov process. Laser acceleration of the particles in the result of the reflection from the pulse envelope and in the capture regime with the variable refraction index along the pulse propagation direction is investigated.
International Nuclear Information System (INIS)
Bulanov, S.V.; Esirkepov, T.Zh.; Kamenets, F.F.; Naumova, N.M.
1995-01-01
The paper presents the results of a numeric modelling of the propagation of ultra short relativistically strong laser pulses in a rarefied plasma by the 'particle in cell'. Primary attention is paid to the process of the formation of electromagnetic solitons which can not be described in the approximation of envelopes. It is found that under certain conditions a significant portion of pulse energy can transform is solitons. The soliton excitation mechanism is related to a decrease of local frequency of electromagnetic radiation due to the generation of wave plasma waves. From one soliton to a stub of solitons can be generated in the wake of a relatively long pulse depending on the parameters of laser pulse in plasma. Particles are effectively accelerated forwards radiation propagation in the electric field of wake plasma waves. 22 refs., 7 figs
Li, An Yong
2007-04-21
Upon formation of a H bond Y...H-XZ, intramolecular hyperconjugation n(Z)-->sigma*(X-H) of the proton donor plays a key role in red- and blueshift characters of H bonds and must be introduced in the concepts of hyperconjugation and rehybridization. Intermolecular hyperconjugation transfers electron density from Y to sigma*(X-H) and causes elongation and stretch frequency redshift of the X-H bond; intramolecular hyperconjugation couples with intermolecular hyperconjugation and can adjust electron density in sigma*(X-H); rehybridization causes contraction and stretch frequency blueshift of the X-H bond on complexation. The three factors--intra- and intermolecular hyperconjugations and rehybridization--determine commonly red- or blueshift of the formed H bond. A proton donor that has strong intramolecular hyperconjugation often forms blueshifted H bonds.
Strongly coupled interaction between a ridge of fluid and an inviscid airflow
Paterson, C.
2015-07-01
© 2015 AIP Publishing LLC. The behaviour of a steady thin sessile or pendent ridge of fluid on an inclined planar substrate which is strongly coupled to the external pressure gradient arising from an inviscid airflow parallel to the substrate far from the ridge is described. When the substrate is nearly horizontal, a very wide ridge can be supported against gravity by capillary and/or external pressure forces; otherwise, only a narrower (but still wide) ridge can be supported. Classical thin-aerofoil theory is adapted to obtain the governing singular integro-differential equation for the profile of the ridge in each case. Attention is focused mainly on the case of a very wide sessile ridge. The effect of strengthening the airflow is to push a pinned ridge down near to its edges and to pull it up near to its middle. At a critical airflow strength, the upslope contact angle reaches the receding contact angle at which the upslope contact line de-pins, and continuing to increase the airflow strength beyond this critical value results in the de-pinned ridge becoming narrower, thicker, and closer to being symmetric in the limit of a strong airflow. The effect of tilting the substrate is to skew a pinned ridge in the downslope direction. Depending on the values of the advancing and receding contact angles, the ridge may first de-pin at either the upslope or the downslope contact line but, in general, eventually both contact lines de-pin. The special cases in which only one of the contact lines de-pins are also considered. It is also shown that the behaviour of a very wide pendent ridge is qualitatively similar to that of a very wide sessile ridge, while the important qualitative difference between the behaviour of a very wide ridge and a narrower ridge is that, in general, for the latter one or both of the contact lines may never de-pin.
DEFF Research Database (Denmark)
Loft, N. J. S.; Marchukov, O. V.; Petrosyan, D.
2016-01-01
We have developed an efficient computational method to treat long, one-dimensional systems of strongly-interacting atoms forming self-assembled spin chains. Such systems can be used to realize many spin chain model Hamiltonians tunable by the external confining potential. As a concrete...... demonstration, we consider quantum state transfer in a Heisenberg spin chain and we show how to determine the confining potential in order to obtain nearly-perfect state transfer....
International Nuclear Information System (INIS)
Bobrov, V.B.; Triger, S.A.
1994-01-01
The effective collision frequency method developed earlier by the authors for Coulomb systems characterized by strong interion interaction is developed further. An explicit expression is obtained for the effective electron collision frequency on the basis of the exact diagram representation obtained in Part I and the use of the model of a one-component plasma as initial approximation. The description of plasma structure in the corresponding approximation is considered. 25 refs
Cao, G.; Terzic, J.; Zhao, H. D.; Zheng, H.; De Long, L. E.; Riseborough, Peter S.
2018-01-01
Electrical control of structural and physical properties is a long-sought, but elusive goal of contemporary science and technology. We demonstrate that a combination of strong spin-orbit interactions (SOI) and a canted antiferromagnetic Mott state is sufficient to attain that goal. The antiferromagnetic insulator Sr2IrO4 provides a model system in which strong SOI lock canted Ir magnetic moments to IrO6 octahedra, causing them to rigidly rotate together. A novel coupling between an applied electrical current and the canting angle reduces the Néel temperature and drives a large, nonlinear lattice expansion that closely tracks the magnetization, increases the electron mobility, and precipitates a unique resistive switching effect. Our observations open new avenues for understanding fundamental physics driven by strong SOI in condensed matter, and provide a new paradigm for functional materials and devices.
International Nuclear Information System (INIS)
Laat, C.T.A.M. de; Taal, A.; Duinker, W.; Konijn, J.; Petitjean, C.; Reist, H.W.; Mueller, W.; Commission of the European Communities, Geel
1987-01-01
The X-ray spectrum of muonic and pionic 237 Np has been investigated with muons and pions stopped in a NpO 2 target. The nuclear spectroscopic quadrupole moment was determined to be Q=3.886±0.006 b from the splittings of the muonic 5g→4f hyperfine complexes. The B(E2)↓-values for the first and second excited states were evaluated as 3.17±0.08 and 2.77±0.10 e 2 b 2 , respectively. A comparison between the muonic and pionic 5g→4f hyperfine complexes yields the strong interaction parameter for the pionic 4f state. For the first time a change of sign as function of Z for the strong interaction quadrupole shift ε 2 (4f) has been observed. The standard optical model predictions agree reasonably well with the measured strong interaction monopole shift, ε 0 (4f), and width, Γ 0 (4f), while they disagree with the experimental value for ε 2 . A stronger s-wave repulsion in the optical potential could explain this effect. (orig.)
International Nuclear Information System (INIS)
Armour, E A G; Liu, Y; Vigier, A
2005-01-01
The aim of experimentalists currently working on the preparation of antihydrogen is to trap it at very low temperatures so that its properties can be studied. Any process that can lead to loss of antihydrogen is thus of great concern to them. In view of this, we have carried out a calculation of the antiproton annihilation cross section in very low-energy hydrogen-antihydrogen scattering using a complex potential to represent the strong interaction that brings about the annihilation. The potential takes into account the isotopic spin state of the proton and the antiproton and the possibility that they may be in either a singlet or a triplet spin state. The results for the annihilation cross section and the percentage change in the elastic cross section due to the inclusion of the strong interaction are similar to those obtained in a recent calculation (Jonsell et al 2004 J. Phys. B: At. Mol. Opt. Phys. 37 1195), using an effective range expansion. They are smaller by a factor of 2 and 3, respectively, than those obtained in an earlier calculation (Voronin and Carbonell 2001 Nucl. Phys. A 689 529c), using a coupled channel method and a complex strong interaction potential. (letter to the editor)
International Nuclear Information System (INIS)
Caldirola, P.; Recami, E.
1978-01-01
By assuming covariance of physical laws under (discrete) dilatations, strong and gravitational interactions have been described in a unified way. In terms of the (additional, discrete) ''dilatational'' degree of freedom, our cosmos as well as hadrons can be considered as different states of the same system, or rather as similar systems. Moreover, a discrete hierarchy can be defined of ''universes'' which are governed by force fields with strengths inversely proportional to the ''universe'' radii. Inside each ''universe'' an equivalence principle holds, so that its characteristic field can be geometrized there. It is thus easy to derive a whole ''numerology'', i.e. relations among numbers analogous to the so-called Weyl-Eddington-Dirac ''large numbers''. For instance, the ''Planck mass'' happens to be nothing but the (average) magnitude of the strong charge of the hadron quarks. However, our ''numerology'' connects the (gravitational) macrocosmos with the (strong) microcosmos, rather than with the electromagnetic ones (as, e.g., in Dirac's version). Einstein-type scaled equations (with ''cosmological'' term) are suggested for the hadron interior, which - incidentally - yield a (classical) quark confinement in a very natural way and are compatible with the ''asymptotic freedom''. At last, within a ''bi-scale'' theory, further equations are proposed that provide a priori a classical field theory of strong interactions (between different hadrons). The relevant sections are 5.2, 7 and 8. (author)
On a low energy, strong interaction model, unifying mesons and baryons
International Nuclear Information System (INIS)
Kalafatis, D.
1993-03-01
This thesis is concerned with the study of a unified theory of mesons and baryons. An effective Lagrangian with the low mass mesons, generalizing the Skyrme model, is constructed. The vector meson fields are introduced as gauge fields in the linear sigma model instead of the non linear sigma model. Topological soliton solutions of the model are examined and the nucleon-nucleon interaction in the product approximation is investigated. The leading correction to the classical skyrmion mass, the Casimir energy, is evaluated. The problem of the stability of topological solitons when vector fields enter the chiral Lagrangian is also studied. It is shown that the soliton is stable in very much the same way as with the ωmeson and that peculiar classical doublet solutions do not exist
RADIO AND X-RAY OBSERVATIONS OF SN 2006jd: ANOTHER STRONGLY INTERACTING TYPE IIn SUPERNOVA
Energy Technology Data Exchange (ETDEWEB)
Chandra, Poonam [Department of Physics, Royal Military College of Canada, Kingston, ON K7K 7B4 (Canada); Chevalier, Roger A.; Irwin, Christopher M. [Department of Astronomy, University of Virginia, P.O. Box 400325, Charlottesville, VA 22904-4325 (United States); Chugai, Nikolai [Institute of Astronomy of Russian Academy of Sciences, Pyatnitskaya Street 48, 109017 Moscow (Russian Federation); Fransson, Claes [Department of Astronomy, Stockholm University, AlbaNova, SE-106 91 Stockholm (Sweden); Soderberg, Alicia M. [Smithsonian Astrophysical Observatory, 60 Garden Street, MS-20, Cambridge, MA 02138 (United States); Chakraborti, Sayan [Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, 1 Homi Bhabha Road, Colaba, Mumbai 400005 (India); Immler, Stefan, E-mail: Poonam.Chandra@rmc.ca [Astrophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
2012-08-20
We report four years of radio and X-ray monitoring of the Type IIn supernova SN 2006jd at radio wavelengths with the Very Large Array, Giant Metrewave Radio Telescope, and Expanded Very Large Array; at X-ray wavelengths with Chandra, XMM-Newton, and Swift-XRT. We assume that the radio and X-ray emitting particles are produced by shock interaction with a dense circumstellar medium. The radio emission shows an initial rise that can be attributed to free-free absorption by cool gas mixed into the nonthermal emitting region; external free-free absorption is disfavored because of the shape of the rising light curves and the low gas column density inferred along the line of sight to the emission region. The X-ray luminosity implies a preshock circumstellar density {approx}10{sup 6} cm{sup -3} at a radius r {approx} 2 Multiplication-Sign 10{sup 16} cm, but the column density inferred from the photoabsorption of X-rays along the line of sight suggests a significantly lower density. The implication may be an asymmetry in the interaction. The X-ray spectrum shows Fe line emission at 6.9 keV that is stronger than is expected for the conditions in the X-ray emitting gas. We suggest that cool gas mixed into the hot gas plays a role in the line emission. Our radio and X-ray data both suggest the density profile is flatter than r{sup -2} because of the slow evolution of the unabsorbed emission.
Interaction of N-hydroxyurea with strong proton donors: HCl and HF
Sałdyka, Magdalena
2014-11-01
An infrared spectroscopic and MP2/6-311++G(2d,2p) study of strong hydrogen bonded complexes of N-hydroxyurea (NH2CONHOH) with hydrogen halides (HCl and HF) trapped in solid argon matrices is reported. 1:1 and 1:2 complexes between N-hydroxyurea and hydrogen chloride, hydrogen fluoride have been identified in the NH2CONHOH/HCl/Ar, NH2CONHOH/HF/Ar matrices, respectively; their structures were determined by comparison of the spectra with the results of calculations. In the 1:1 complexes, identified for both hydrogen halide molecules, the cyclic structure stabilized by the X-H⋯O and N-H⋯X bonds is present; for the NH2CONHOH⋯HF system another isomeric 1:1 complex is also observed. Two 1:2 complexes were identified for the N-hydroxyurea-hydrogen chloride system characterised by the Cl-H⋯O and N-H⋯Cl bonds. The results of the study evidence that N-hydroxyurea is an oxygen base in the gas-phase with the carbonyl group as the strongest proton acceptor centre in the molecule.
Inelastic strong interactions at high energies. Annual progress report, June 1, 1979-May 1, 1980
International Nuclear Information System (INIS)
Suranyi, P.
1980-02-01
Investigations in the area of Grand Unified Field Theories were begun. Various ways of breaking the SU(5) symmetric theory of Georgi and Glashow were studied. As usual, an approx. 24 of Higgs breaks the symmetry from SU(5) to SU(3)/sub c/xSU(2)xU(1). It was found that an approx. 45 of Higgs is acceptable for breaking the symmetry from SU(3)/sub c/xSU(2)xU(1) to SU(3)/sub c/xU(1)/sub em/. In addition phenomenologically correct quark-lepton mass ratios are obtained by use of renormalization-group techniques if there are 6 generations of particles in the theory. Efforts directed at the development of approximate methods for extracting information from quantum field theories were continued. The quantum mechanics of polynomial potentials as a model for quantum field theories was investigated. A perturbation expansion for the energy levels and wave functions was constructed and has been proven to be convergent for arbitrary values of the coupling constants, in contrast to ordinary perturbation expansions that have a zero radius of convergence. The physical significance of the new perturbation expansions was explored both in the weak and strong coupling limits
Direct measurements of intermolecular forces by chemical force microscopy
Vezenov, Dmitri Vitalievich
1999-12-01
Detailed description of intermolecular forces is key to understanding a wide range of phenomena from molecular recognition to materials failure. The unique features of atomic force microscopy (AFM) to make point contact force measurements with ultra high sensitivity and to generate spatial maps of surface topography and forces have been extended to include measurements between well-defined organic molecular groups. Chemical modification of AFM probes with self-assembled monolayers (SAMs) was used to make them sensitive to specific molecular interactions. This novel chemical force microscopy (CFM) technique was used to probe forces between different molecular groups in a range of environments (vacuum, organic liquids and aqueous solutions); measure surface energetics on a nanometer scale; determine pK values of the surface acid and base groups; measure forces to stretch and unbind a short synthetic DNA duplex and map the spatial distribution of specific functional groups and their ionization state. Studies of adhesion forces demonstrated the important contribution of hydrogen bonding to interactions between simple organic functionalities. The chemical identity of the tip and substrate surfaces as well as the medium had a dramatic effect on adhesion between model monolayers. A direct correlation between surface free energy and adhesion forces was established. The adhesion between epoxy polymer and model mixed SAMs varied with the amount of hydrogen bonding component in the monolayers. A consistent interpretation of CFM measurements in polar solvents was provided by contact mechanics models and intermolecular force components theory. Forces between tips and surfaces functionalized with SAMs terminating in acid or base groups depended on their ionization state. A novel method of force titration was introduced for highly local characterization of the pK's of surface functional groups. The pH-dependent changes in friction forces were exploited to map spatially the
International Nuclear Information System (INIS)
Yang, Yi; Steup, M.
1990-01-01
From leaves of Spinacia oleracea L. or from Pisum sativum L. and from cotyledons of germinating pea seeds a high molecular weight polysaccharide fraction was isolated. The apparent size of the fraction, as determined by gel filtration, was similar to that of dextran blue. Following acid hydrolysis the monomer content of the polysaccharide preparation was studied using high pressure liquid and thin layer chromatography. Glucose, galactose, arabinose, and ribose were the main monosaccharide compounds. The native polysaccharide preparation interacted strongly with the cytosolic isozyme of phosphorylase (EC 2.4.1.1). Interaction with the plastidic phosphorylase isozyme(s) was by far weaker. Interaction with the cytosolic isozyme was demonstrated by affinity electrophoresis, kinetic measurements, and by 14 C-labeling experiments in which the glucosyl transfer from [ 14 C]glucose 1-phosphate to the polysaccharide preparation was monitored
International Nuclear Information System (INIS)
Sherman, A.; Schreiber, M.
1995-01-01
We use the Eliashberg formalism for calculating T c in a model of cuprate perovskites with pairing mediated by both magnons and apex-oxygen vibrations. The influence of strong correlations on the energy spectrum is taken into account in the spin-wave approximation. It is shown that the hole-magnon interaction alone cannot yield high T c . But together with a moderate hole-phonon interaction it does lead to d-wave superconductivity at temperatures and hole concentrations observed in cuprates. High T c are connected with a large density of states due to extended Van Hove singularities, a conformity of the two interactions for the d symmetry, and high phonon frequencies
Powers, Lydia
The National Museum of Play at The Strong's Dancing Wings Butterfly Garden is a tropical rainforest that allows visitors to step into the world of butterflies, but lacks a more comprehensive educational element to teach visitors additional information about butterflies. Flutter-by Interactive Butterfly is a thesis project designed to enhance younger visitors' experience of the Dancing Wings Butterfly Garden with an interactive educational application that aligns with The Strong's mission of encouraging learning, creativity, and discovery. This was accomplished through a series of fun and educational games and animations, designed for use as a kiosk outside the garden and as a part of The Strong's website. Content, planning, and organization of this project has been completed through research and observation of the garden in the following areas: its visitors, butterflies, best usability practices for children, and game elements that educate and engage children. Flutter-by Interactive Butterfly teaches users about the butterfly's life cycle, anatomy, and characteristics as well as their life in the Dancing Wings Butterfly Garden. Through the use of the design programs Adobe Illustrator, Flash, and After Effects; the programming language ActionScript3.0; a child-friendly user interface and design; audio elements and user takeaways, Flutter-by Interactive Butterfly appeals to children of all ages, interests, and learning styles. The project can be viewed at lydiapowers.com/Thesis/FlutterByButterfly.html
The iodine molecule insights into intra- and intermolecular perturbation in diatomic molecules
Lukashov, Sergey; Pravilov, Anatoly
2018-01-01
This book presents experimental and theoretical spectroscopic studies performed over the last 25 years on the iodine molecule’s excited states and their perturbations. It is going to be of interest to researchers who study intra- and intermolecular perturbations in diatomic molecules and more complex systems. The book offers a detailed treatment of the nonadiabatic perturbations of valence, ion pair and Rydberg states induced by intramolecular as well as intermolecular interactions in collisions or in weakly-bound complexes. It also provides an overview of current instrumentation and techniques as well as theoretical approaches describing intra- and intermolecular perturbations. The authors are experts in the use of spectroscopy for the study of intrinsic and collision-induced perturbations in diatomic iodine. They introduced new methods of two- and three-step optical population of the iodine ion-pair states. The iodine molecule has 23 valence states correlating with three dissociation limits, 20 so-called ...
Exploring effects of strong interactions in enhancing masses of dynamical origin
International Nuclear Information System (INIS)
Cabo Montes de Oca, Alejandro
2011-01-01
A previous study of the dynamical generation of masses in massless QCD is considered from another viewpoint. The quark mass is assumed to have a dynamical origin and is substituted for by a scalar field without self-interaction. The potential for the new field background is evaluated up to two loops. Expressing the running coupling in terms of the scale parameter μ, the potential minimum is chosen to fix m top =175 GeV when μ 0 =498 MeV. The second derivative of the potential predicts a scalar field mass of 126.76 GeV. This number is close to the value 114 GeV, which preliminary data taken at CERN suggested to be associated with the Higgs particle. However, the simplifying assumptions limit the validity of the calculations done, as indicated by the large value of α=(g 2 )/(4π)=1.077 obtained. However, supporting statements about the possibility of improving the scheme come from the necessary inclusion of weak and scalar field couplings and mass counterterms in the renormalization procedure, in common with the seemingly needed consideration of the massive W and Z fields, if the real conditions of the SM model are intended to be approached. (orig.)
Some issues linked to the description of systems in strong interaction
International Nuclear Information System (INIS)
Theussl, L.
2001-06-01
In the first part of this work we have dealt with some issues that are relevant in the area of nucleonic resonances within different constituent quark models. In this context we have concentrated on the theoretical description of Pi and Nu decays for N and Delta resonances. The results obtained point to the necessity of a more microscopic description of the dynamics which is at the same time responsible for the binding of quarks inside baryons and the decay of the latter ones. In the second part we have contributed to the study of crossed two-boson exchanges in the Bethe-Salpeter equation as well as to the investigation of different three-dimensional approaches that follow from the Bethe-Salpeter equation in a certain non-relativistic reduction scheme. These one include in particular an equation whose interaction depends on the total energy of the system. It was shown that such an equation is able to account for a certain number of properties of Bethe-Salpeter equation, in particular, that there also arise abnormal solutions in such an approach. (author)
Electron Fluid Description of Wave-Particle Interactions in Strong Buneman Turbulence
Che, Haihong
2013-10-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation associated with electron heating in Buneman instability. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions can be described by a set of electron fluid equations. These equations show that the energy dissipation and momentum transports in Buneman instability are locally quasi-static but globally non-static and irreversible. Turbulence drag dissipates both the bulk energy of electron streams and the associated magnetic energy. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons. The net loss of streaming energy is converted into electron heat and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation which relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drives local momentum transports, while phase mixing converts convective momentum into thermal momentum.These two local momentum transports sustain the Buneman waves and act as the micro-macro link in the anomalous heating process. This research is supported by the NASA Postdoctoral Program at NASA/GSFC administered by Oak Ridge Associated Universities through a contract with NASA.
Two-fluid description of wave-particle interactions in strong Buneman turbulence
Energy Technology Data Exchange (ETDEWEB)
Che, H. [NASA/Goddard Space Flight Center, Greenbelt, Maryland 20771 (United States)
2014-06-15
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability.
Two-fluid description of wave-particle interactions in strong Buneman turbulence
Che, H.
2014-06-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability.
Two-fluid description of wave-particle interactions in strong Buneman turbulence
International Nuclear Information System (INIS)
Che, H.
2014-01-01
To understand the nature of anomalous resistivity in magnetic reconnection, we investigate turbulence-induced momentum transport and energy dissipation while a plasma is unstable to the Buneman instability in force-free current sheets. Using 3D particle-in-cell simulations, we find that the macroscopic effects generated by wave-particle interactions in Buneman instability can be approximately described by a set of electron fluid equations. We show that both energy dissipation and momentum transport along electric current in the current layer are locally quasi-static, but globally dynamic and irreversible. Turbulent drag dissipates both the streaming energy of the current sheet and the associated magnetic energy. The net loss of streaming energy is converted into the electron component heat conduction parallel to the magnetic field and increases the electron Boltzmann entropy. The growth of self-sustained Buneman waves satisfies a Bernoulli-like equation that relates the turbulence-induced convective momentum transport and thermal momentum transport. Electron trapping and de-trapping drive local momentum transports, while phase mixing converts convective momentum into thermal momentum. The drag acts like a micro-macro link in the anomalous heating processes. The decrease of magnetic field maintains an inductive electric field that re-accelerates electrons, but most of the magnetic energy is dissipated and converted into the component heat of electrons perpendicular to the magnetic field. This heating process is decoupled from the heating of Buneman instability in the current sheets. Ion heating is weak but ions play an important role in assisting energy exchanges between waves and electrons. Cold ion fluid equations together with our electron fluid equations form a complete set of equations that describes the occurrence, growth, saturation and decay of the Buneman instability
International Nuclear Information System (INIS)
Voskresenskaya, O.O.
2002-01-01
It is shown that the relations between probabilities of A 2π -atoms creation in ns-states, derived with neglecting of the strong interaction between pions, hold practically unchanged if the strong interaction is taken into account in the first order of the perturbation theory. The formulation of Deser equation for the energy levels shift of the hadronic atoms (HA) is given in terms of the effective range of the strong interaction and relative correction to the Coulomb wave function of HA at origin, caused by the strong interaction. (author)
Cirhin up-regulates a canonical NF-{kappa}B element through strong interaction with Cirip/HIVEP1
Energy Technology Data Exchange (ETDEWEB)
Yu, Bin; Mitchell, Grant A. [Genetique Medicale, Centre de Recherche CHU Sainte-Justine, Departement de Pediatrie, Universite de Montreal, Montreal, QC (Canada); Richter, Andrea, E-mail: andrea.richter@umontreal.ca [Genetique Medicale, Centre de Recherche CHU Sainte-Justine, Departement de Pediatrie, Universite de Montreal, Montreal, QC (Canada)
2009-11-01
North American Indian childhood cirrhosis (NAIC/CIRH1A) is a severe autosomal recessive intrahepatic cholestasis. All NAIC patients have a homozygous mutation in CIRH1A that changes conserved Arg565 to Trp (R565W) in Cirhin, a nucleolar protein of unknown function. Subcellular localization is unaffected by the mutation. Yeast two-hybrid screening identified Cirip (Cirhin interaction protein) and found that interaction between Cirip and R565W-Cirhin was weakened. Co-immunoprecipitation of the two proteins from nuclear extracts of HeLa cells strongly supports the yeast two hybrid results. Cirip has essentially the same sequence as the C-terminal of HIVEP1, a regulator of a canonical NF-{kappa}B sequence. Since Cirip has the zinc fingers required for this interaction, we developed an in vitro assay based on this element in mammalian cells to demonstrate functional Cirhin-Cirip interaction. The strong positive effect of Cirip on the NF-{kappa}B sequence was further increased by both Cirhin and R565W-Cirhin. Importantly, the effect of R565W-Cirhin was weaker than that of the wild type protein. We observed increased levels of Cirhin-Cirip complex in nuclear extracts in the presence of this NF-{kappa}B sequence. Our hypothesis is that Cirhin is a transcriptional regulatory factor of this NF-{kappa}B sequence and could be a participant in the regulation of other genes with NF-{kappa}B responsive elements. Since the activities of genes regulated through NF-{kappa}B responsive elements are especially important during development, this interaction may be a key to explain the perinatal appearance of NAIC.
Cirhin up-regulates a canonical NF-κB element through strong interaction with Cirip/HIVEP1
International Nuclear Information System (INIS)
Yu, Bin; Mitchell, Grant A.; Richter, Andrea
2009-01-01
North American Indian childhood cirrhosis (NAIC/CIRH1A) is a severe autosomal recessive intrahepatic cholestasis. All NAIC patients have a homozygous mutation in CIRH1A that changes conserved Arg565 to Trp (R565W) in Cirhin, a nucleolar protein of unknown function. Subcellular localization is unaffected by the mutation. Yeast two-hybrid screening identified Cirip (Cirhin interaction protein) and found that interaction between Cirip and R565W-Cirhin was weakened. Co-immunoprecipitation of the two proteins from nuclear extracts of HeLa cells strongly supports the yeast two hybrid results. Cirip has essentially the same sequence as the C-terminal of HIVEP1, a regulator of a canonical NF-κB sequence. Since Cirip has the zinc fingers required for this interaction, we developed an in vitro assay based on this element in mammalian cells to demonstrate functional Cirhin-Cirip interaction. The strong positive effect of Cirip on the NF-κB sequence was further increased by both Cirhin and R565W-Cirhin. Importantly, the effect of R565W-Cirhin was weaker than that of the wild type protein. We observed increased levels of Cirhin-Cirip complex in nuclear extracts in the presence of this NF-κB sequence. Our hypothesis is that Cirhin is a transcriptional regulatory factor of this NF-κB sequence and could be a participant in the regulation of other genes with NF-κB responsive elements. Since the activities of genes regulated through NF-κB responsive elements are especially important during development, this interaction may be a key to explain the perinatal appearance of NAIC.
International Nuclear Information System (INIS)
Lundberg, Pernilla; Koskinen, Cecilia; Baldock, Paul A.; Loethgren, Hanna; Stenberg, Asa; Lerner, Ulf H.; Oldenborg, Per-Arne
2007-01-01
Physical interaction between the cell surface receptors CD47 and signal regulatory protein alpha (SIRPα) was reported to regulate cell migration, phagocytosis, cytokine production, and macrophage fusion. However, it is unclear if the CD47/SIRPα-interaction can also regulate macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor (NF)-κB ligand (RANKL)-stimulated formation of osteoclasts. Here, we show that functional blocking antibodies to either CD47 or SIRPα strongly reduced formation of multinucleated tartrate-resistant acid phosphatase (TRAP) + osteoclasts in cultures of murine hematopoietic cells, stimulated in vitro by M-CSF and RANKL. In addition, the numbers of osteoclasts formed in M-CSF/RANKL-stimulated bone marrow macrophage cultures from CD47 -/- mice were strongly reduced, and bones of CD47 -/- mice exhibited significantly reduced osteoclast numbers, as compared with wild-type controls. We conclude that the CD47/SIRPα interaction is important for M-CSF/RANKL-stimulated osteoclast formation both in vivo and in vitro, and that absence of CD47 results in decreased numbers of osteoclasts in CD47 -/- mice
Hargart, F.; Roy-Choudhury, K.; John, T.; Portalupi, S. L.; Schneider, C.; Höfling, S.; Kamp, M.; Hughes, S.; Michler, P.
2016-12-01
In this work we present an extensive experimental and theoretical investigation of different regimes of strong field light-matter interaction for cavity-driven quantum dot (QD) cavity systems. The electric field enhancement inside a high-Q micropillar cavity facilitates exceptionally strong interaction with few cavity photons, enabling the simultaneous investigation for a wide range of QD-laser detuning. In case of a resonant drive, the formation of dressed states and a Mollow triplet sideband splitting of up to 45 μeV is measured for a mean cavity photon number ≤slant 1. In the asymptotic limit of the linear AC Stark effect we systematically investigate the power and detuning dependence of more than 400 QDs. Some QD-cavity systems exhibit an unexpected anomalous Stark shift, which can be explained by an extended dressed 4-level QD model. We provide a detailed analysis of the QD-cavity systems properties enabling this novel effect. The experimental results are successfully reproduced using a polaron master equation approach for the QD-cavity system, which includes the driving laser field, exciton-cavity and exciton-phonon interactions.