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Sample records for vibrationally energized molecules

  1. Spectroscopy and reactions of vibrationally excited transient molecules

    Energy Technology Data Exchange (ETDEWEB)

    Dai, H.L. [Univ. of Pennsylvania, Philadelphia (United States)

    1993-12-01

    Spectroscopy, energy transfer and reactions of vibrationally excited transient molecules are studied through a combination of laser-based excitation techniques and efficient detection of emission from the energized molecules with frequency and time resolution. Specifically, a Time-resolved Fourier Transform Emission Spectroscopy technique has been developed for detecting dispersed laser-induced fluorescence in the IR, visible and UV regions. The structure and spectroscopy of the excited vibrational levels in the electronic ground state, as well as energy relaxation and reactions induced by specific vibronic excitations of a transient molecule can be characterized from time-resolved dispersed fluorescence in the visible and UV region. IR emissions from highly vibrational excited levels, on the other hand, reveal the pathways and rates of collision induced vibrational energy transfer.

  2. Isotope separation using vibrationally excited molecules

    International Nuclear Information System (INIS)

    Woodroffe, J.A.; Keck, J.C.

    1979-01-01

    Vibrational excitation of molecules having components of a selected isotope type is used to produce a conversion from vibrational to translational excitation of the molecules by collision with the molecules of a heavy carrier gas. The resulting difference in translaton between the molecules of the selected isotope type and all other molecules of the same compound permits their separate collection. When applied to uranium enrichment, a subsonic cryogenic flow of molecules of uranium hexafluoride in combination with an argon carrier gas is directed through a cooled chamber that is illuminated by laser radiaton tuned to vibrationally excite the uranium hexafluoride molecules of a specific uranium isotope. The excited molecules collide with carrier gas molecules, causing a conversion of the excitation energy into a translation of the excited molecule, which results in a higher thermal energy or diffusivity than that of the other uranium hexafluoride molecules. The flowing molecules including the excited molecules directly enter a set of cryogenically cooled channels. The higher thermal velocity of the excited molecules increases the probability of their striking a collector surface. The molecules which strike this surface immediately condense. After a predetermined thickness of molecules is collected on the surface, the flow of uranium hexafluoride is interrupted and the chamber heated to the point of vaporization of the collected hexafluoride, permitting its removal. (LL)

  3. Isotope separation using vibrationally excited molecules

    International Nuclear Information System (INIS)

    Woodroffe, J.A.; Keck, J.C.

    1977-01-01

    A system for isotope separation or enrichment wherein molecules of a selected isotope type in a flow of molecules of plural isotope types are vibrationally excited and collided with a background gas to provide enhanced diffusivity for the molecules of the selected isotope type permitting their separate collection. The system typically is for the enrichment of uranium using a uranium hexafluoride gas in combination with a noble gas such as argon. The uranium hexafluoride molecules having a specific isotope of uranium are vibrationally excited by laser radiation. The vibrational energy is converted to a translation energy upon collision with a particle of the background gas and the added translation energy enhances the diffusivity of the selected hexafluoride molecules facilitating its condensation on collection surfaces provided for that purpose. This process is periodically interrupted and the cryogenic flow halted to permit evaporation of the collected molecules to provide a distinct, enriched flow

  4. Analytic vibrational matrix elements for diatomic molecules

    International Nuclear Information System (INIS)

    Bouanich, J.P.; Ogilvie, J.F.; Tipping, R.H.

    1986-01-01

    The vibrational matrix elements and expectation values for a diatomic molecule, including the rotational dependence, are calculated for powers of the reduced displacement in terms of the parameters of the Dunham potential-energy function. (orig.)

  5. Classical dynamics of triatomic system: energized harmonic molecules

    International Nuclear Information System (INIS)

    Parr, C.A.; Kuppermann, A.; Porter, R.N.

    1976-01-01

    The dynamical assumptions underlying the Slater and RRK classical-mechanical theories of unimolecular reaction rates are investigated. The predictions of these theories for several nonlinear, triatomic, harmonically-bonded molecular models are compared with the results obtained from the integration of the classical equations of motion. The accuracy of the small-vibration and weak-coupling assumptions are found to break down at energies above about one quarter of a bond dissociation energy. Nonetheless, the small-vibration approximation predicts reaction frequencies in good agreement with the exact results for the models. The effects of rotation on intramolecular energy exchange are examined and found to be significant

  6. Studies of interstellar vibrationally-excited molecules

    International Nuclear Information System (INIS)

    Ziurys, L.M.; Snell, R.L.; Erickson, N.R.

    1986-01-01

    Several molecules thus far have been detected in the ISM in vibrationally-excited states, including H 2 , SiO, HC 3 N, and CH 3 CN. In order for vibrational-excitation to occur, these species must be present in unusually hot and dense gas and/or where strong infrared radiation is present. In order to do a more thorough investigation of vibrational excitation in the interstellar medium (ISM), studies were done of several mm-wave transitions originating in excited vibrational modes of HCN, an abundant interstellar molecule. Vibrationally-excited HCN was recently detected toward Orion-KL and IRC+10216, using a 12 meter antenna. The J=3-2 rotational transitions were detected in the molecule's lowest vibrational state, the bending mode, which is split into two separate levels, due to l-type doubling. This bending mode lies 1025K above ground state, with an Einstein A coefficient of 3.6/s. The J=3-2 line mode of HCN, which lies 2050K above ground state, was also observed toward IRC+10216, and subsequently in Orion-KL. Further measurements of vibrationally-excited HCN were done using a 14 meter telescope, which include the observations of the (0,1,0) and (0,2,0) modes towards Orion-KL, via their J=3-2 transitions at 265-267 GHz. The spectrum of the J=3-2 line in Orion taken with the 14 meter telescope, is shown, along with a map, which indicates that emission from vibrationally-excited HCN arises from a region probably smaller than the 14 meter telescope's 20 arcsec beam

  7. Quantum Monte Carlo for vibrating molecules

    International Nuclear Information System (INIS)

    Brown, W.R.; Lawrence Berkeley National Lab., CA

    1996-08-01

    Quantum Monte Carlo (QMC) has successfully computed the total electronic energies of atoms and molecules. The main goal of this work is to use correlation function quantum Monte Carlo (CFQMC) to compute the vibrational state energies of molecules given a potential energy surface (PES). In CFQMC, an ensemble of random walkers simulate the diffusion and branching processes of the imaginary-time time dependent Schroedinger equation in order to evaluate the matrix elements. The program QMCVIB was written to perform multi-state VMC and CFQMC calculations and employed for several calculations of the H 2 O and C 3 vibrational states, using 7 PES's, 3 trial wavefunction forms, two methods of non-linear basis function parameter optimization, and on both serial and parallel computers. In order to construct accurate trial wavefunctions different wavefunctions forms were required for H 2 O and C 3 . In order to construct accurate trial wavefunctions for C 3 , the non-linear parameters were optimized with respect to the sum of the energies of several low-lying vibrational states. In order to stabilize the statistical error estimates for C 3 the Monte Carlo data was collected into blocks. Accurate vibrational state energies were computed using both serial and parallel QMCVIB programs. Comparison of vibrational state energies computed from the three C 3 PES's suggested that a non-linear equilibrium geometry PES is the most accurate and that discrete potential representations may be used to conveniently determine vibrational state energies

  8. Spectroscopic and dynamical studies of highly energized small polyatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Field, R.W.; Silbey, R.J. [Massachusetts Institute of Technology, Cambridge (United States)

    1993-12-01

    The authors have initiated a program to perform spectroscopic and dynamic studies of small molecules. Large amplitude motions in excited acetylene were discussed along with plans to record the dispersed fluorescence (DF) and the stimulated emission pumping (SEP) spectra. SEP spectra were reported for the formyl radical. A Fourier transform spectrometer was discussed with respect to its ability to probe the structure of radicals. This instrument is capable of performing studies using various techniques such as magnetic rotation spectroscopy and sub-Doppler sideband-OODR Zeman (SOODRZ) spectroscopy.

  9. The photodissociation and reaction dynamics of vibrationally excited molecules

    Energy Technology Data Exchange (ETDEWEB)

    Crim, F.F. [Univ. of Wisconsin, Madison (United States)

    1993-12-01

    This research determines the nature of highly vibrationally excited molecules, their unimolecular reactions, and their photodissociation dynamics. The goal is to characterize vibrationally excited molecules and to exploit that understanding to discover and control their chemical pathways. Most recently the author has used a combination of vibrational overtone excitation and laser induced fluorescence both to characterize vibrationally excited molecules and to study their photodissociation dynamics. The author has also begun laser induced grating spectroscopy experiments designed to obtain the electronic absorption spectra of highly vibrationally excited molecules.

  10. selective excitation of vibrational modes of polyatomic molecule

    Indian Academy of Sciences (India)

    Abstract. Mode-selective dynamics of triatomic molecule in the electronic ground state under continuous wave laser pulse is investigated for the discrete vibrational bound states. A non-perturbative approach has been used to analyse the vibrational couplings and dynamics of the molecule. Keywords. Polyatomic molecule ...

  11. Isotope separation using vibrationally excited molecules

    International Nuclear Information System (INIS)

    1979-01-01

    This invention relates to isotope separation employing isotopically selective vibrational excitation and vibration-translation reactions of the excited particles. Uranium enrichment, using uranium hexafluoride, is a particular embodiment. (U.K.)

  12. Test-Anchored Vibration Response Predictions for an Acoustically Energized Curved Orthogrid Panel with Mounted Components

    Science.gov (United States)

    Frady, Gregory P.; Duvall, Lowery D.; Fulcher, Clay W. G.; Laverde, Bruce T.; Hunt, Ronald A.

    2011-01-01

    rich body of vibroacoustic test data was recently generated at Marshall Space Flight Center for component-loaded curved orthogrid panels typical of launch vehicle skin structures. The test data were used to anchor computational predictions of a variety of spatially distributed responses including acceleration, strain and component interface force. Transfer functions relating the responses to the input pressure field were generated from finite element based modal solutions and test-derived damping estimates. A diffuse acoustic field model was applied to correlate the measured input sound pressures across the energized panel. This application quantifies the ability to quickly and accurately predict a variety of responses to acoustically energized skin panels with mounted components. Favorable comparisons between the measured and predicted responses were established. The validated models were used to examine vibration response sensitivities to relevant modeling parameters such as pressure patch density, mesh density, weight of the mounted component and model form. Convergence metrics include spectral densities and cumulative root-mean squared (RMS) functions for acceleration, velocity, displacement, strain and interface force. Minimum frequencies for response convergence were established as well as recommendations for modeling techniques, particularly in the early stages of a component design when accurate structural vibration requirements are needed relatively quickly. The results were compared with long-established guidelines for modeling accuracy of component-loaded panels. A theoretical basis for the Response/Pressure Transfer Function (RPTF) approach provides insight into trends observed in the response predictions and confirmed in the test data. The software developed for the RPTF method allows easy replacement of the diffuse acoustic field with other pressure fields such as a turbulent boundary layer (TBL) model suitable for vehicle ascent. Structural responses

  13. Diatomic molecule vibrational potentials: Accuracy of representations

    International Nuclear Information System (INIS)

    Engelke, R.

    1978-01-01

    A method is presented for increasing the radius of convergence of certain representations of diatomic molecule vibrational potentials. The method relies on using knowledge of the analytic structure of such potentials to the maximum when attempting to approximate them. The known singular point (due to the centrifugal and/or Coulomb potentials) at zero internuclear separation should be included in its exact form in an approximate representation. The efficacy of this idea is tested [using Peek's ''exact'' numerical Born-Oppenheimer potential for the (1ssigma/sub g/) 2 Σ + /sub g/ state of H + 2 as a test problem] when the representational form is the series of (1) Dunham, (2) Simons, Parr, and Finlan, (3) Thakkar, and (4) Ogilvie-Tipping, and also (5) when the form is a [2, 2] or a [3, 3] Pade approximant. Significant improvements in accuracy are obtained in some of these cases, particularly on the inner wall of the potential. A comparison of the effectiveness of the five methods is made both with and without the origin behavior being included exactly. This is useful in itself as no comprehensive accuracy comparison of the standard representations seems to have appeared in the literature. The Ogilvie-Tipping series, corrected at the origin for singular behavior, is the best representation presently available for states analogous to the (1ssigma/sub g/) 2 Σ + /sub g/ state of H + 2

  14. Analytic vibration-rotational matrix elements for diatomic molecules

    International Nuclear Information System (INIS)

    Bouanich, J.P.

    1987-01-01

    The vibration-rotational matrix elements for infrared or Raman transitions vJ → v'J' of diatomic molecules are calculated for powers of the reduced displacement X from parameters of the Dunham potential-energy function. (orig.)

  15. Vibrations of a molecule in an external force field.

    Science.gov (United States)

    Okabayashi, Norio; Peronio, Angelo; Paulsson, Magnus; Arai, Toyoko; Giessibl, Franz J

    2018-05-01

    The oscillation frequencies of a molecule on a surface are determined by the mass distribution in the molecule and the restoring forces that occur when the molecule bends. The restoring force originates from the atomic-scale interaction within the molecule and with the surface, which plays an essential role in the dynamics and reactivity of the molecule. In 1998, a combination of scanning tunneling microscopy with inelastic tunneling spectroscopy revealed the vibrational frequencies of single molecules adsorbed on a surface. However, the probe tip itself exerts forces on the molecule, changing its oscillation frequencies. Here, we combine atomic force microscopy with inelastic tunneling spectroscopy and measure the influence of the forces exerted by the tip on the lateral vibrational modes of a carbon monoxide molecule on a copper surface. Comparing the experimental data to a mechanical model of the vibrating molecule shows that the bonds within the molecule and with the surface are weakened by the proximity of the tip. This combination of techniques can be applied to analyze complex molecular vibrations and the mechanics of forming and loosening chemical bonds, as well as to study the mechanics of bond breaking in chemical reactions and atomic manipulation.

  16. Spectroscopic probes of vibrationally excited molecules at chemically significant energies

    Energy Technology Data Exchange (ETDEWEB)

    Rizzo, T.R. [Univ. of Rochester, NY (United States)

    1993-12-01

    This project involves the application of multiple-resonance spectroscopic techniques for investigating energy transfer and dissociation dynamics of highly vibrationally excited molecules. Two major goals of this work are: (1) to provide information on potential energy surfaces of combustion related molecules at chemically significant energies, and (2) to test theoretical modes of unimolecular dissociation rates critically via quantum-state resolved measurements.

  17. Vibrational-rotational excitation: chemical reactions of vibrationally excited molecules

    International Nuclear Information System (INIS)

    Moore, C.B.; Smith, I.W.M.

    1979-03-01

    This review considers a limited number of systems, particularly gas-phase processes. Excited states and their preparation, direct bimolecular reactions, reactions of highly excited molecules, and reactions in condensed phases are discussed. Laser-induced isotope separation applications are mentioned briefly. 109 references

  18. Vibrationally coupled electron transport through single-molecule junctions

    Energy Technology Data Exchange (ETDEWEB)

    Haertle, Rainer

    2012-04-26

    Single-molecule junctions are among the smallest electric circuits. They consist of a molecule that is bound to a left and a right electrode. With such a molecular nanocontact, the flow of electrical currents through a single molecule can be studied and controlled. Experiments on single-molecule junctions show that a single molecule carries electrical currents that can even be in the microampere regime. Thereby, a number of transport phenomena have been observed, such as, for example, diode- or transistor-like behavior, negative differential resistance and conductance switching. An objective of this field, which is commonly referred to as molecular electronics, is to relate these transport phenomena to the properties of the molecule in the contact. To this end, theoretical model calculations are employed, which facilitate an understanding of the underlying transport processes and mechanisms. Thereby, one has to take into account that molecules are flexible structures, which respond to a change of their charge state by a profound reorganization of their geometrical structure or may even dissociate. It is thus important to understand the interrelation between the vibrational degrees of freedom of a singlemolecule junction and the electrical current flowing through the contact. In this thesis, we investigate vibrational effects in electron transport through singlemolecule junctions. For these studies, we calculate and analyze transport characteristics of both generic and first-principles based model systems of a molecular contact. To this end, we employ a master equation and a nonequilibrium Green's function approach. Both methods are suitable to describe this nonequilibrium transport problem and treat the interactions of the tunneling electrons on the molecular bridge non-perturbatively. This is particularly important with respect to the vibrational degrees of freedom, which may strongly interact with the tunneling electrons. We show in detail that the resulting

  19. A study of vibrational relaxation of electronically-excited molecules

    International Nuclear Information System (INIS)

    Datsyuk, V.V.; Izmailov, I.A.; Kochelap, V.A.

    1992-09-01

    The time kinetics of the vibrational relaxation of excimers is studied in the diffusional approximation. Simple formulae for functions of nonstationary vibrational distribution are found for the electronically excited molecules. Some spectral-kinetic dependencies of the excimer luminescence are explained in a new way. The possibilities of the determination of excimer parameters are discussed. The dependence of energetical characteristics of excimer lasers on these parameters is particularly emphasized. (author). 22 refs, 5 figs

  20. The origin of small and large molecule behavior in the vibrational relaxation of highly excited molecules

    International Nuclear Information System (INIS)

    Gordon, R.J.

    1990-01-01

    An explanation is proposed for the qualitatively different types of behavior that have been reported for the vibrational relaxation of highly excited diatomic and polyatomic molecules. It is argued that all of the diatomic molecules that have been studied in bulk relax adiabatically at room temperature. In contrast, large polyatomic molecules have low frequency modes which act at ''doorway'' modes for the rest of the molecules, producing an impulsive relaxation mechanism. The theoretical work of Nesbitt and Hynes showed that impulsive collisions result in an exponential decay of the average vibrational energy of a Morse oscillator, whereas adiabatic collisions produce nonexponential power law behavior. We propose that this result explains a large body of data for the vibrational relaxation of small and large molecules

  1. Vibrational relaxation induced population inversions in laser pumped polyatomic molecules

    International Nuclear Information System (INIS)

    Shamah, I.; Flynn, G.; Columbia Univ., New York

    1981-01-01

    Conditions for population inversion in laser pumped polyatomic molecules are described. For systems which exhibit metastable vibrational population distributions, large, long lived inversions are possible even when the vibrational modes are strongly coupled by rapid collisional vibration-vibration (V-V) energy transfer. Overtone states of a hot mode are found to invert with respect to fundamental levels of a cold mode even at V-V steady state. Inversion persists for a V-T/R relaxation time. A gain of 4 m -1 for the 2ν 3 → ν 2 transition in CH 3 F (lambda approx. 15.9 μ) was found assuming a spontaneous emission lifetime of 10 s for this transition. General equations are derived which can be used to determine the magnitude of population inversion in any laser pumped, vibrationally metastable, polyatomic molecule. A discussion of factors controlling the population maxima of different vibrational states in optically pumped, V-V equilibrated metastable polyatomics is also given. (orig./WL)

  2. Experimental determination of vibrational cross sections for diatomic molecules

    International Nuclear Information System (INIS)

    Noqueira, J.C.; Iga, I.; Lee Mu Tao; Lopes, M.C.A.; Almeida, D.P. de

    1988-01-01

    To obtain inelastic differential cross sections from electronic and vibrational molecular excitations by electron impact, it was constructed a new spectrometer to operate in the energy range from 100 to 500 eV. The deceleration lenses as well as the analyser were tested for nitrogen molecule and 350 eV electrons. (A.C.A.S.) [pt

  3. Neutral molecules in tokamak edge plasma - role of vibrationally excited hydrogen molecules

    International Nuclear Information System (INIS)

    Cadez, I.; Cercek, M.; Pelicon, P.; Razpet, A.

    2003-01-01

    The role of neutral molecules in edge plasma is discussed with special emphasis on the vibrationally excited hydrogen. Neutral molecules are formed mostly by surface processes on the walls and then released to the edge plasma where they take part in volumetric reactions with other particles. Typically these molecules are formed in excited states and data are needed for their reactions on the wall and in the volume. Processes in edge plasma determine particle and energy flux what is especially critical issue in tokamak divertor region. Various cross sections and reaction rates are needed for modelling edge plasma and its interaction with walls. (author)

  4. Vibrational properties of water molecules adsorbed in different zeolitic frameworks

    International Nuclear Information System (INIS)

    Crupi, V; Longo, F; Majolino, D; Venuti, V

    2006-01-01

    The perturbation of water 'sorbed' in samples of zeolites of different structural type, genesis, and cation composition (K-, Na-, Mg- and Ca-rich zeolites), namely the CHA framework of a synthetic K-chabazite, the LTA framework of synthetic Na-A and Mg50-A zeolites, and the NAT framework of a natural scolecite, has been studied by FTIR-ATR spectroscopy, in the -10 to +80 o C temperature range. The aim was to show how differences in the chemical composition and/or in the topology of the zeolite framework and, in particular, the possibility for the guest water molecules to develop guest-guest and/or host-guest interactions, lead to substantial differences in their vibrational dynamical properties. The spectra, collected in the O-H stretching and H 2 O bending mode regions, are complex, with multiple bands being observed. As far as water in the CHA and LTA frameworks is concerned, whose behaviour is governed by the balance of water-water, water-framework and water-extra-framework cations interactions, the assignment of the resolved components of the O-H stretching band has been discussed by fitting the band shapes into individual components attributed to H 2 O molecules engaged in different degrees of hydrogen bonding. A detailed quantitative picture of the connectivity pattern of water, as a function of temperature and according to the chemical and topological properties of the environment, is furnished. The H 2 O bending vibrational bands give additional information that perfectly agrees with the results obtained from the analysis of the O-H stretching spectral region. In the case of scolecite, a small-pored zeolite where water-water interactions are eliminated, the increased complexity observed in the infrared spectra in the O-H stretching and H 2 O bending regions was explained as due to the hydrogen bonding between the water molecules and the network, and also with the extra-framework cation. Furthermore, these observations have been correlated with the different

  5. Process and system for isotope separation using the selective vibrational excitation of molecules

    International Nuclear Information System (INIS)

    Woodroffe, J.A.; Keck, J.C.

    1976-01-01

    This invention concerns the separation of isotopes by using the isotopically selective vibrational excitation and the vibration-translation reactions of the excited particles. UF 6 molecular mixed with a carrier gas, such as argon, are directed through a refrigerated chamber lighted by a laser radiation tuned to excite vibrationally the uranium hexafluoride molecules of a particular uranium isotope. The density of the carrier gas is preferably maintained above the density of the uranium hexafluoride to allow a greater collision probability of the vibrationally excited molecules with a carried molecule. In such a case, the vibrationally excited uranium hexafluoride will collide with a carrier gas molecule provoking the conversion of the excitation energy into a translation of the excited molecule, resulting in thermal energy or greater diffusibility than that of the other uranium hexafluoride molecules [fr

  6. Correlating the vibrational spectra of structurally related molecules: A spectroscopic measure of similarity.

    Science.gov (United States)

    Tao, Yunwen; Zou, Wenli; Cremer, Dieter; Kraka, Elfi

    2018-03-05

    Using catastrophe theory and the concept of a mutation path, an algorithm is developed that leads to the direct correlation of the normal vibrational modes of two structurally related molecules. The mutation path is defined by weighted incremental changes in mass and geometry of the molecules in question, which are successively applied to mutate a molecule into a structurally related molecule and thus continuously converting their normal vibrational spectra from one into the other. Correlation diagrams are generated that accurately relate the normal vibrational modes to each other by utilizing mode-mode overlap criteria and resolving allowed and avoided crossings of vibrational eigenstates. The limitations of normal mode correlation, however, foster the correlation of local vibrational modes, which offer a novel vibrational measure of similarity. It will be shown how this will open new avenues for chemical studies. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  7. Effect of deuteration on the vibrational spectra of organic molecules

    International Nuclear Information System (INIS)

    Billes, Ferenc; Endredi, Henrietta; Varady, Balazs

    2001-01-01

    The stable isotope substitution of organic compounds deforms their vibrational spectra. The modifications of the spectra appear as band shifts and changes in intensities and shapes of the bands. The magnitude of the effect depends on the ratio of the masses of the new and old isotopes and on the atom active position. According to these mentioned reasons large effects can be observed only if hydrogen atoms are substituted. With the effect of the substitution we dealt already in a former lecture. In this lecture we concentrate on the effect of the change of hydrogen to deuterium. We investigate the changes both experimentally and theoretically. There are two possibilities: - the hydrogen atom is in an active position, its interaction with the environment is strong, either it can dissociate or move on the skeleton of the molecule (tautomerism, resonance) and it can build hydrogen bond, (e.g. it is connected to nitrogen and oxygen atoms); - the hydrogen atom is in an indifferent position in the molecule, its interaction with the environment is weak (e.g. it joins carbon atom). When building the hydrogen bond besides the hydrogen donors also acceptors exist, namely, oxygen and nitrogen atoms having non-bonded electron pairs. When comparing the experimental and theoretical (calculated) effects of this type of isotope changes one must take into account that the calculations refer to the isolated molecule while the experimental spectra characterize the compound. The hydrogen bond is a very strong intermolecular interaction and produces tremendous changes in the infrared spectrum of the molecule in comparison to the imagined theoretical spectrum of the molecule. Some bands disappear, appear, or shift and deform drastically. The H/D change diminishes these effects. Of course, these changes entail the shift of several bands. The Raman spectrum is less sensitive to the large dipole moment changes therefore the deuteration effect is there less dramatic. Deuteration of hydrogen

  8. Diatomic-molecule vibrational potentials. II. New representationsa)

    International Nuclear Information System (INIS)

    Engelke, R.

    1979-01-01

    Two new representations of diatomic-molecule vibrational potentials are presented. One of these includes most of the previously employed series approximations as special cases. The new representations are tested against older ones by using Peek's ''exact'' numerical Born--Oppenheimer potentials for the 1ssigma/sub g/, 2pπ/sub u/, and 3dsigma/sub g/ states of H 2 + as test problems. Accuracy comparisons are made with Dunham, Thakkar, Ogilvie--Tipping, Coulomb-subtracted Ogilvie--Tipping, and Pade representations. A central idea of the new treatment is that it is not necessary to use a global representation of the potential over the region 0 or =1 and then match them smoothly to each other and to the Dunham expansion at R/R/sub e/=1. Attention is focused on finding improved approximations for R/R/sub e/>1, since this region exerts strong control on the vibrational eigenvalue spectrum and it is here, perhaps, where the older techniques are at their weakest. Known properties of the exact potential such as the R→infinity behavior and the dissociation energy can be built into the new forms a priori. If the dissociation energy is not known, the new methods allow it to be estimated with better accuracy then could be done previously. If one knows only Dunham coefficients, the Coulomb-subtracted Ogilvie--Tipping series is the superior representation. If one knows, in addition, the dissociation energy, the new representations are superior and give more accurate results on the interval R/R/sub e/> or =1

  9. Vibration-rotation band intensities in the IR spectra of polyatomic molecules

    International Nuclear Information System (INIS)

    El'kin, M.D.; Kosterina, E.K.; Berezin

    1995-01-01

    Using the curvilinear vibrational coordinates for a nuclear subsystem, expressions for the effective dipole-moment operators are derived in order to analyze the vibrational-rotational transitions in the IR spectra of polyatomic rigid molecules. The explicit expressions obtained for the intensities of hot bands allow one to estimate the influence of the vibration-rotation interaction within the framework of the adopted molecular-vibration model. The suggested method is shown to be suitable for Raman spectra analysis. 12 refs

  10. Nonlinear quantum dynamics in diatomic molecules: Vibration, rotation and spin

    International Nuclear Information System (INIS)

    Yang, Ciann-Dong; Weng, Hung-Jen

    2012-01-01

    Highlights: ► This paper reveals the internal nonlinear dynamics embedded in a molecular quantum state. ► Analyze quantum molecular dynamics in a deterministic way, while preserving the consistency with probability interpretation. ► Molecular vibration–rotation interaction and spin–orbital coupling are considered simultaneously. ► Spin is just the remnant angular motion when orbital angular momentum is zero. ► Spin is the “zero dynamics” of nonlinear quantum dynamics. - Abstract: For a given molecular wavefunction Ψ, the probability density function Ψ ∗ Ψ is not the only information that can be extracted from Ψ. We point out in this paper that nonlinear quantum dynamics of a diatomic molecule, completely consistent with the probability prediction of quantum mechanics, does exist and can be derived from the quantum Hamilton equations of motion determined by Ψ. It can be said that the probability density function Ψ ∗ Ψ is an external representation of the quantum state Ψ, while the related Hamilton dynamics is an internal representation of Ψ, which reveals the internal mechanism underlying the externally observed random events. The proposed internal representation of Ψ establishes a bridge between nonlinear dynamics and quantum mechanics, which allows the methods and tools already developed by the former to be applied to the latter. Based on the quantum Hamilton equations of motion derived from Ψ, vibration, rotation and spin motions of a diatomic molecule and the interactions between them can be analyzed simultaneously. The resulting dynamic analysis of molecular motion is compared with the conventional probability analysis and the consistency between them is demonstrated.

  11. Asymptotically-correct description of vibration-rotation spectrum of diatomic molecule with hydrogen iodide molecule as example

    International Nuclear Information System (INIS)

    Burenin, A.V.; Ryabikin, M.Yu.

    1990-01-01

    Asymptotically correct series of perturbation theory was constructed analytically to describe the vibration-rotational spectrum of diatomic molecule in Born-Oppenheimer approximation. The series was used for processing of precision experimental data on frequencies of absorption of hydrogen iodide molecule. Advantage of this approach over Dunham approach is shown. Isotope ratios for spectroscopic constants of asymptotically correct series are considered

  12. Interaction of spin and vibrations in transport through single-molecule magnets

    Directory of Open Access Journals (Sweden)

    Falk May

    2011-10-01

    Full Text Available We study electron transport through a single-molecule magnet (SMM and the interplay of its anisotropic spin with quantized vibrational distortions of the molecule. Based on numerical renormalization group calculations we show that, despite the longitudinal anisotropy barrier and small transverse anisotropy, vibrational fluctuations can induce quantum spin-tunneling (QST and a QST-Kondo effect. The interplay of spin scattering, QST and molecular vibrations can strongly enhance the Kondo effect and induce an anomalous magnetic field dependence of vibrational Kondo side-bands.

  13. Interaction of spin and vibrations in transport through single-molecule magnets.

    Science.gov (United States)

    May, Falk; Wegewijs, Maarten R; Hofstetter, Walter

    2011-01-01

    We study electron transport through a single-molecule magnet (SMM) and the interplay of its anisotropic spin with quantized vibrational distortions of the molecule. Based on numerical renormalization group calculations we show that, despite the longitudinal anisotropy barrier and small transverse anisotropy, vibrational fluctuations can induce quantum spin-tunneling (QST) and a QST-Kondo effect. The interplay of spin scattering, QST and molecular vibrations can strongly enhance the Kondo effect and induce an anomalous magnetic field dependence of vibrational Kondo side-bands.

  14. Approximative Krieger-Nelkin orientation averaging and anisotropy of water molecules vibrations

    International Nuclear Information System (INIS)

    Markovic, M.I.

    1974-01-01

    Quantum-mechanics approach of water molecules dynamics should be taken into account for precise theoretical calculation of differential scattering cross sections of neutrons. Krieger and Nelkin have proposed an approximate method for averaging orientation of molecules regarding directions of incoming and scattered neutron. This paper shows that this approach can be successfully applied for general shape of water molecule vibration anisotropy

  15. Vibrational frame transformation for electron-molecule scattering

    International Nuclear Information System (INIS)

    Greene, C.H.; Jungen, C.

    1985-01-01

    The frame-transformation theory of electron interaction with a vibrating diatomic core is extended to allow for energy dependence of its parameters. The Born-Oppenheimer separation of electron and nuclear motion is preserved when the electron penetrates the molecular core. The extended theory reproduces the boomerang-model treatment of vibrational excitation in resonant e-N 2 collisions

  16. Single-molecule electronics: Cooling individual vibrational modes by the tunneling current.

    Science.gov (United States)

    Lykkebo, Jacob; Romano, Giuseppe; Gagliardi, Alessio; Pecchia, Alessandro; Solomon, Gemma C

    2016-03-21

    Electronic devices composed of single molecules constitute the ultimate limit in the continued downscaling of electronic components. A key challenge for single-molecule electronics is to control the temperature of these junctions. Controlling heating and cooling effects in individual vibrational modes can, in principle, be utilized to increase stability of single-molecule junctions under bias, to pump energy into particular vibrational modes to perform current-induced reactions, or to increase the resolution in inelastic electron tunneling spectroscopy by controlling the life-times of phonons in a molecule by suppressing absorption and external dissipation processes. Under bias the current and the molecule exchange energy, which typically results in heating of the molecule. However, the opposite process is also possible, where energy is extracted from the molecule by the tunneling current. Designing a molecular "heat sink" where a particular vibrational mode funnels heat out of the molecule and into the leads would be very desirable. It is even possible to imagine how the vibrational energy of the other vibrational modes could be funneled into the "cooling mode," given the right molecular design. Previous efforts to understand heating and cooling mechanisms in single molecule junctions have primarily been concerned with small models, where it is unclear which molecular systems they correspond to. In this paper, our focus is on suppressing heating and obtaining current-induced cooling in certain vibrational modes. Strategies for cooling vibrational modes in single-molecule junctions are presented, together with atomistic calculations based on those strategies. Cooling and reduced heating are observed for two different cooling schemes in calculations of atomistic single-molecule junctions.

  17. Observation of the adsorption and desorption of vibrationally excited molecules on a metal surface

    Science.gov (United States)

    Shirhatti, Pranav R.; Rahinov, Igor; Golibrzuch, Kai; Werdecker, Jörn; Geweke, Jan; Altschäffel, Jan; Kumar, Sumit; Auerbach, Daniel J.; Bartels, Christof; Wodtke, Alec M.

    2018-06-01

    The most common mechanism of catalytic surface chemistry is that of Langmuir and Hinshelwood (LH). In the LH mechanism, reactants adsorb, become thermalized with the surface, and subsequently react. The measured vibrational (relaxation) lifetimes of molecules adsorbed at metal surfaces are in the range of a few picoseconds. As a consequence, vibrational promotion of LH chemistry is rarely observed, with the exception of LH reactions occurring via a molecular physisorbed intermediate. Here, we directly detect adsorption and subsequent desorption of vibrationally excited CO molecules from a Au(111) surface. Our results show that CO (v = 1) survives on a Au(111) surface for 1 × 10-10 s. Such long vibrational lifetimes for adsorbates on metal surfaces are unexpected and pose an interesting challenge to the current understanding of vibrational energy dissipation on metal surfaces. They also suggest that vibrational promotion of surface chemistry might be more common than is generally believed.

  18. Analysis of rotation-vibration relative equilibria on the example of a tetrahedral four atom molecule

    NARCIS (Netherlands)

    Efstathiou, K; Sadovskii, DA; Zhilinskii, BI

    2004-01-01

    We study relative equilibria ( RE) of a nonrigid molecule, which vibrates about a well-defined equilibrium configuration and rotates as a whole. Our analysis unifies the theory of rotational and vibrational RE. We rely on the detailed study of the symmetry group action on the initial and reduced

  19. A Pictorial Visualization of Normal Mode Vibrations of the Fullerene (C[subscript 60]) Molecule in Terms of Vibrations of a Hollow Sphere

    Science.gov (United States)

    Dunn, Janette L.

    2010-01-01

    Understanding the normal mode vibrations of a molecule is important in the analysis of vibrational spectra. However, the complicated 3D motion of large molecules can be difficult to interpret. We show how images of normal modes of the fullerene molecule C[subscript 60] can be made easier to understand by superimposing them on images of the normal…

  20. Spectroscopy of vibrationally hot molecules: Hydrogen cyanide and acetylene

    International Nuclear Information System (INIS)

    Jonas, D.M.

    1992-01-01

    An efficient formula for calculating nuclear spin statistical weights is presented. New experimental methods to distinguish electric and magnetic multipole transitions are proposed and used to prove that the formaldehyde A - X 0-0 transition is a magnetic dipole transition. HIgh resolution vacuum ultraviolet studies of the A → X fluorescence excitation spectrum of hydrogen cyanide (HCN) have: (i) determined that only the (0,1,0) vibrational level of the HCN A-state has a sufficiently long fluorescence lifetime to be suitable for Stimulated Emission Pumping (SEP) studies; and (ii) measured the electric dipole moment of the A-state. Several transitions in the hydrogen cyanide A → X SEP spectrum are shown to be due to the axis-switching mechanism. From a Franck-Condon plot of the intensities and a comparison between sums of predicted rotational constants and sums of observed rotational constants, all of the remaining transitions in the SEP spectrum can be securly assigned. Two weak resonances; a 2:3 CH:CN stretch Fermi resonance and a 6:2 bend:CN stretch resonance appear in the SEP spectrum. Excitation of the CH stretching vibration is predicted and shown to be entirely absent, apart from resonances, in the HCN SEP spectrum. A → X SEP spectra of acetylene (HCCH) near E VIB = 7,000 cm -1 display a wealth of strong and fully assignable anharmonic resonances and forbidden rotational transitions. It is proved that Darling-Dennison resonance between the cis and trans bending vibrations is the crucial first step in a series of anharmonic resonances which can transfer nearly all the vibrational energy out of the initial CC stretch/trans-bend excitation at high vibrational energy. Secondary steps in the vibrational energy flow are vibrational-l-resonance and the '2345' Fermi resonance. For short times, the vibrational energy redistribution obeys very restrictive rules

  1. Chemical reactions of water molecules on Ru(0001) induced by selective excitation of vibrational modes

    Energy Technology Data Exchange (ETDEWEB)

    Mugarza, Aitor; Shimizu, Tomoko K.; Ogletree, D. Frank; Salmeron, Miquel

    2009-05-07

    Tunneling electrons in a scanning tunneling microscope were used to excite specific vibrational quantum states of adsorbed water and hydroxyl molecules on a Ru(0 0 0 1) surface. The excited molecules relaxed by transfer of energy to lower energy modes, resulting in diffusion, dissociation, desorption, and surface-tip transfer processes. Diffusion of H{sub 2}O molecules could be induced by excitation of the O-H stretch vibration mode at 445 meV. Isolated molecules required excitation of one single quantum while molecules bonded to a C atom required at least two quanta. Dissociation of single H{sub 2}O molecules into H and OH required electron energies of 1 eV or higher while dissociation of OH required at least 2 eV electrons. In contrast, water molecules forming part of a cluster could be dissociated with electron energies of 0.5 eV.

  2. Theoretical study of molecular vibration and Application to linear triatomic molecules: case of OCS

    International Nuclear Information System (INIS)

    Andrianavalomahefa, A.

    2014-01-01

    Our aim is to give a theoretical approach to the calculation of vibrational energy levels of polyatomic molecules. By using matrix calculation, we have to solve an eigenvalue equation that gives normal vibration frequencies of the system. A basis change introduces normal coordinates of vibration, which diagonalize the Hamiltonian. The harmonic approximation gives a rough evaluation of parameters which describe the system. Then, we introduce nonlinear terms to take into account the anharmonicity of interatomic bounds. Morse oscillator gives good approximation for diatomic molecules. We consider cubic and quartic potential terms for polyatomic molecules. We treat the problem both in classical and quantum approach. The results thus obtained are applied to study longitudinal vibration of carbonyl sulfide. [fr

  3. Vibrational-rotational relaxation of the simplest hydrogen-containing molecules (review)

    International Nuclear Information System (INIS)

    Molevich, N.E.; Oraevskii, A.N.

    1987-01-01

    In connection with the development of chemical lasers much attention is now devoted to the study of kinetic processes is gaseous mixtures containing the hydrogen halides. Vibrational relaxation of molecules if primarily studied without specifying its relation to the rational levels. Rotational relaxation is regarded a priori as faster than vibrational relaxation, so that the population of the rotational levels is assumed to be in equilibrium. This approach to the relaxation of hydrogen halide molecules (and other diatomic hydrogen-containing molecules), however, is unable to explain satisfactorily the results of the papers discussed below. An analysis of the data obtained in these papers leads to the conclusion that the general picture of relaxation in diatomic hydrogen-containing molecules must be viewed as a unified process of vibrational and rotational relaxation. It is shown that those effects observed during vibrational relaxation of such molecules which are unusual from the standpoint of the theory of vibrational-translational relaxation are well explained in terms of intermolecular vibrational-rotational relaxation together with pure rotational relaxation

  4. Rotation-vibrational spectra of diatomic molecules and nuclei with Davidson interactions

    CERN Document Server

    Rowe, D J

    1998-01-01

    Complete rotation-vibrational spectra and electromagnetic transition rates are obtained for Hamiltonians of diatomic molecules and nuclei with Davidson interactions. Analytical results are derived by dynamical symmetry methods for diatomic molecules and a liquid-drop model of the nucleus. Numerical solutions are obtained for a many-particle nucleus with quadrupole Davidson interactions within the framework of the microscopic symplectic model. (author)

  5. Vibrational emission analysis of the CN molecules in laser-induced breakdown spectroscopy of organic compounds

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-Bravo, Ángel; Delgado, Tomás; Lucena, Patricia; Laserna, J. Javier, E-mail: laserna@uma.es

    2013-11-01

    Laser-induced breakdown spectroscopy (LIBS) of organic materials is based on the analysis of atomic and ionic emission lines and on a few molecular bands, the most important being the CN violet system and the C{sub 2} Swan system. This paper is focused in molecular emission of LIBS plasmas based on the CN (B{sup 2}Σ–X{sup 2}Σ) band, one of the strongest emissions appearing in all carbon materials when analyzed in air atmosphere. An analysis of this band with sufficient spectral resolution provides a great deal of information on the molecule, which has revealed that valuable information can be obtained from the plume chemistry and dynamics affecting the excitation mechanisms of the molecules. The vibrational emission of this molecular band has been investigated to establish the dependence of this emission on the molecular structure of the materials. The paper shows that excitation/emission phenomena of molecular species observed in the plume depend strongly on the time interval selected and on the irradiance deposited on the sample surface. Precise time resolved LIBS measurements are needed for the observation of distinctive CN emission. For the organic compounds studied, larger differences in the behavior of the vibrational emission occur at early stages after plasma ignition. Since molecular emission is generally more complex than that involving atomic emission, local plasma conditions as well as plume chemistry may induce changes in vibrational emission of molecules. As a consequence, alterations in the distribution of the emissions occur in terms of relative intensities, being sensitive to the molecular structure of every single material. - Highlights: • Vibrational emission of CN species in laser-induced plasmas has been investigated. • Distribution of vibrational emission of CN has been found to be time dependent. • Laser irradiance affects the vibrational distribution of the CN molecules. • Plume chemistry controls the excitation mechanisms of CN

  6. Analysis of micro vibration in gas film of aerostatic guide way based on molecule collision theory

    Directory of Open Access Journals (Sweden)

    Yang Shao Hua

    2016-01-01

    Full Text Available Micro vibration of the aerostatic guide way has a significant impact on its dynamic characteristics and stability, which limits the development of pneumatic component. High pressure gas molecules have been collided with the supporting surface and the internal surface of the throttle during the flow process. Variable impulse of the surfaces aside for the gas film are affected by the changes of impulse which formed irregular impact force in horizontal and vertical direction. Micro-vibration takes place based on the natural frequency of the system and its frequency doubling. In this paper, the vibration model was established to describe the dynamic characteristics of the gas film, and the formation mechanism of micro vibration in the film is defined. Through the simulation analysis and experimental comparison, formation mechanism of the micro vibration in the gas film is confirmed. It was proposed that the micro vibration of gas film can be produced no matter whether there is a gas chamber or not in the throttle. Under the same conditions, the micro vibration of the guide way with air chamber is greater than that without any chamber. The frequency points of the vibration peaks are almost the same, as well as the vibration pattern in the frequency domain.

  7. Quasi continuum vibrational of molecules and isotopic selectivity properties induced by collisions

    International Nuclear Information System (INIS)

    Angelie, Christian

    1990-01-01

    This research thesis proposes an overview of knowledge on vibrationally highly excited states of molecules. The author shows that the statistic quasi-continuum formed by these states is preceded by a quasi continuum of weak transitions with a lower energy, and that these transitions remain structured and very narrow up to the dissociation energy and beyond. Collisions between molecules excited in their quasi continuum are then studied. The author particularly analyses a new phenomenon of isotopic selectivity which is important for the dissociation of a molecule colliding another molecule. It appears that this selectivity regarding selectivity is due to a selectivity of transferred energy which paradoxically increases with the molecule vibrational content because of a resonance phenomenon of energies transferred by dipole-dipole interaction [fr

  8. Femtosecond time-resolved studies of coherent vibrational Raman scattering in large gas-phase molecules

    International Nuclear Information System (INIS)

    Hayden, C.C.; Chandler, D.W.

    1995-01-01

    Results are presented from femtosecond time-resolved coherent Raman experiments in which we excite and monitor vibrational coherence in gas-phase samples of benzene and 1,3,5-hexatriene. Different physical mechanisms for coherence decay are seen in these two molecules. In benzene, where the Raman polarizability is largely isotropic, the Q branch of the vibrational Raman spectrum is the primary feature excited. Molecules in different rotational states have different Q-branch transition frequencies due to vibration--rotation interaction. Thus, the macroscopic polarization that is observed in these experiments decays because it has many frequency components from molecules in different rotational states, and these frequency components go out of phase with each other. In 1,3,5-hexatriene, the Raman excitation produces molecules in a coherent superposition of rotational states, through (O, P, R, and S branch) transitions that are strong due to the large anisotropy of the Raman polarizability. The coherent superposition of rotational states corresponds to initially spatially oriented, vibrationally excited, molecules that are freely rotating. The rotation of molecules away from the initial orientation is primarily responsible for the coherence decay in this case. These experiments produce large (∼10% efficiency) Raman shifted signals with modest excitation pulse energies (10 μJ) demonstrating the feasibility of this approach for a variety of gas phase studies. copyright 1995 American Institute of Physics

  9. Kinetics of highly vibrationally excited O2(X) molecules in inductively-coupled oxygen plasmas

    Science.gov (United States)

    Annušová, Adriana; Marinov, Daniil; Booth, Jean-Paul; Sirse, Nishant; Lino da Silva, Mário; Lopez, Bruno; Guerra, Vasco

    2018-04-01

    The high degree of vibrational excitation of O2 ground state molecules recently observed in inductively coupled plasma discharges is investigated experimentally in more detail and interpreted using a detailed self-consistent 0D global kinetic model for oxygen plasmas. Additional experimental results are presented and used to validate the model. The vibrational kinetics considers vibrational levels up to v = 41 and accounts for electron impact excitation and de-excitation (e-V), vibration-to-translation relaxation (V-T) in collisions with O2 molecules and O atoms, vibration-to-vibration energy exchanges (V-V), excitation of electronically excited states, dissociative electron attachment, and electron impact dissociation. Measurements were performed at pressures of 10–80 mTorr (1.33 and 10.67 Pa) and radio frequency (13.56 MHz) powers up to 500 W. The simulation results are compared with the absolute densities in each O2 vibrational level obtained by high sensitivity absorption spectroscopy measurements of the Schumann–Runge bands for O2(X, v = 4–18), O(3 P) atom density measurements by two-photon absorption laser induced fluorescence (TALIF) calibrated against Xe, and laser photodetachment measurements of the O‑ negative ions. The highly excited O2(X, v) distribution exhibits a shape similar to a Treanor-Gordiets distribution, but its origin lies in electron impact e-V collisions and not in V-V up-pumping, in contrast to what happens in all other molecular gases known to date. The relaxation of vibrational quanta is mainly due to V-T energy-transfer collisions with O atoms and to electron impact dissociation of vibrationally excited molecules, e+O2(X, v)→O(3P)+O(3P).

  10. Numerical solutions of anharmonic vibration of BaO and SrO molecules

    Energy Technology Data Exchange (ETDEWEB)

    Pramudito, Sidikrubadi; Sanjaya, Nugraha Wanda [Theoretical Physics Division, Department of Physics, Bogor Agricultural University, Jalan Meranti Kampus IPB Dramaga Bogor 16680 (Indonesia); Sumaryada, Tony, E-mail: tsumaryada@ipb.ac.id [Theoretical Physics Division, Department of Physics, Bogor Agricultural University, Jalan Meranti Kampus IPB Dramaga Bogor 16680 (Indonesia); Computational Biophysics and Molecular Modeling Research Group (CBMoRG), Department of Physics, Bogor Agricultural University, Jalan Meranti Kampus IPB Dramaga Bogor 16680 (Indonesia)

    2016-03-11

    The Morse potential is a potential model that is used to describe the anharmonic behavior of molecular vibration between atoms. The BaO and SrO molecules, which are two almost similar diatomic molecules, were investigated in this research. Some of their properties like the value of the dissociation energy, the energy eigenvalues of each energy level, and the profile of the wavefunctions in their correspondence vibrational states were presented in this paper. Calculation of the energy eigenvalues and plotting the wave function’s profiles were performed using Numerov method combined with the shooting method. In general we concluded that the Morse potential solved with numerical methods could accurately produce the vibrational properties and the wavefunction behavior of BaO and SrO molecules from the ground state to the higher states close to the dissociation level.

  11. Vibrational energy transfer in selectively excited diatomic molecules

    International Nuclear Information System (INIS)

    Dasch, C.J.

    1978-09-01

    Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295 0 K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295 0 K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ΔJ transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references

  12. Translational vibrations between chains of hydrogen-bonded molecules in solid-state aspirin form I

    Science.gov (United States)

    Takahashi, Masae; Ishikawa, Yoichi

    2013-06-01

    We perform dispersion-corrected first-principles calculations, and far-infrared (terahertz) spectroscopic experiments at 4 K, to examine translational vibrations between chains of hydrogen-bonded molecules in solid-state aspirin form I. The calculated frequencies and relative intensities reproduce the observed spectrum to accuracy of 11 cm-1 or less. The stronger one of the two peaks assigned to the translational mode includes the stretching vibration of the weak hydrogen bond between the acetyl groups of a neighboring one-dimensional chain. The calculation of aspirin form II performed for comparison gives the stretching vibration of the weak hydrogen bond in one-dimensional chain.

  13. Multiple scattering approach to the vibrational excitation of molecules by slow electrons

    International Nuclear Information System (INIS)

    Drukarev, G.

    1976-01-01

    Another approach to the problem of vibrational excitation of homonuclear two-atomic molecules by slow electrons possibly accompanied by rotational transitions is presented based on the picture of multiple scattering of an electron inside the molecule. The scattering of two fixed centers in the zero range potential model is considered. The results indicate that the multiple scattering determines the order of magnitude of the vibrational excitation cross sections in the energy region under consideration even if the zero range potential model is used. Also the connection between the multiple scattering approach and quasi-stationary molecular ion picture is established. 9 refs

  14. Antibonding intermediate state in the theory of vibrational excitation of diatomic molecules by slow electrons

    International Nuclear Information System (INIS)

    Kazanskii, A.K.

    1982-01-01

    An exactly solvable model is constructed for the description of the processes that take place when a slow electron collides with a diatomic molecule (vibrational excitation, associative detachment, and dissociative attachment). As a particular model of the variant, the case of an antibonding (virtual) state of an intermediate state is considered, and a term of this state is parametrized in a very simple manner. The vibrational excitation and dissociative attachment are calculated for a system corresponding to the HCl molecule. The results are in good qualitative agreement with experiment

  15. Experimental studies of processes with vibrationally excited hydrogen molecules that are important for tokamak edge plasma

    International Nuclear Information System (INIS)

    Cadez, I.; Markelj, S.; Rupnik, Z.; Pelicon, P.

    2006-01-01

    We are currently conducting a series of different laboratory experimental studies of processes involving vibrationally excited hydrogen molecules that are relevant to fusion edge plasma. A general overview of our activities is presented together with results of studies of hydrogen recombination on surfaces. This includes vibrational spectroscopy of molecules formed by recombination on metal surfaces exposed to the partially dissociated hydrogen gas and recombination after hydrogen permeation through metal membrane. The goal of these studies is to provide numerical parameters needed for edge plasma modelling and better understanding of plasma wall interaction processes. (author)

  16. Experimental Evidence for Quantum Interference and Vibrationally Induced Decoherence in Single-Molecule Junctions

    Science.gov (United States)

    Ballmann, Stefan; Härtle, Rainer; Coto, Pedro B.; Elbing, Mark; Mayor, Marcel; Bryce, Martin R.; Thoss, Michael; Weber, Heiko B.

    2012-08-01

    We analyze quantum interference and decoherence effects in single-molecule junctions both experimentally and theoretically by means of the mechanically controlled break junction technique and density-functional theory. We consider the case where interference is provided by overlapping quasidegenerate states. Decoherence mechanisms arising from electronic-vibrational coupling strongly affect the electrical current flowing through a single-molecule contact and can be controlled by temperature variation. Our findings underline the universal relevance of vibrations for understanding charge transport through molecular junctions.

  17. Catalytic synthesis of ammonia using vibrationally excited nitrogen molecules

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Henriksen, Niels Engholm; Billing, Gert D.

    1992-01-01

    The dissociation of nitrogen is the rate-limiting step in the catalytic synthesis of ammonia. Theoretical calculations have shown that the dissociative sticking probability of molecular nitrogen on catalytic active metal surfaces is enhanced by orders of magnitude when the molecules...

  18. Analytic description of highly excited vibrational-rotational states of diatomic molecules: II. Application to the hydrogen chloride molecule

    International Nuclear Information System (INIS)

    Burenin, A.V.; Ryabikin, M.Y.

    1995-01-01

    Processing of the precise experimental data on transition frequencies and energy levels in the ground electronic state of the H 35 Cl molecule was carried out on the basis of the asymptotically correct perturbation series analytically constructed to describe the discrete vibrational-rotational spectrum of a diatomic molecule. The perturbation series was shown to converge rapidly up to the dissociation energy E D , whereas the conventional Dunham series has a distinct limit of applicability equal to 0.39E D . 12 refs., 2 figs

  19. Rotational and vibrational synthetic spectra of linear parent molecules in comets

    International Nuclear Information System (INIS)

    Crovisier, J.

    1987-01-01

    We evaluate and model the excitation conditions of linear parent molecules in cometary atmospheres. The model is valid for most linear molecules without electronic angular momentum. It takes into account collisions and infrared excitation. The molecule rotational population distribution is computed as a function of distance to nucleus. The line intensities of the strongest parallel and perpendicular fundamental vibrational bands, as well as the pure rotational lines, can then be evaluated. This model is applied to several candidate parent molecules, for observing conditions corresponding to available or planned instruments, either ground-based or aboard aircrafts, satellites or space probes

  20. Structural characterization of chiral molecules using vibrational circular dichroism spectroscopy

    DEFF Research Database (Denmark)

    Lassen, Peter Rygaard

    2006-01-01

    comparison of experimental and calculated spectra. Theoretical structures of the sample molecules were constructed and optimized using molecular mechanical force fields followed by the quantum mechanical method density functional theory (DFT). Calculations of IR absorption and VCD spectra were then carried...... out using the same DFT methods. Here, VCD has the advantage over CD that time-independent DFT calculations are sufficient. During the course of this project, the above methodology has been applied to a range of molecules. Some of them (nyasol, curcuphenol dimers and ginkgolide) are purely organic...... or as flexible as the curcuphenol dimer with 11 variable dihedral angles. This illustrates the capabilities of the method, which are primarily limited by the duration of DFT calculations. In the case of metal complexes, they have only recently become within reach of DFT, which opens new possibilities...

  1. Interference between vibration-to-translation and vibration-to-vibration energy transfer modes in diatomic molecules at high collision energies

    International Nuclear Information System (INIS)

    Shin, H.K.

    1983-01-01

    An explicit time dependent approach for simultaneous VT and VV energy transfer in diatom--diatom collisions is explored using the exponential form of ladder operators in the solution of the Schroedinger equation of motion. The collision of two hydrogen molecules is chosen to illustrate the extent of interference between VT and VV modes among various vibrational states. While vibrational energy transfer processes of nominally VT type can be treated with pure VT mode at low collision energies, the intermode coupling is found to be very important at collision energies of several hω. The occurrence of the coupling appears to be nearly universal in vibrational transitions at such energies. Exceptions to the coupling have been discussed

  2. Molecular structure and vibrational spectra of 6-methylquinoline and 8-methylquinoline molecules by quantum mechanical methods

    International Nuclear Information System (INIS)

    Kurt, M.

    2005-01-01

    The molecular geometry and vibrational frequencies of 6-methylquinoline(6MQ) and 8-methylquinolines(8MQ) in the ground state have been calculated by using the Hartree-Fock and density functional methods (B3LYP and BLYP) with 6-31G (d) as the basis set. The optimized geometric bond lengths obtained by using B3LYP and bond angles obtained by BLYP were given corresponding experimental values of similar molecule. Comparison of the observed fundamental vibrational frequencies of these molecules and calculated results by density functional B3LYP, BLYP and Hartree-Fock methods indicates that B3LYP is superior to the scaled Hartree- Fock and BLYP approach for molecular vibrational problems

  3. Influence of vibrations of gas molecules on neutron reaction cross sections

    Science.gov (United States)

    Bowman, C. D.; Schrack, R. A.

    1980-01-01

    The change in molecular vibrational energy upon absorption of a neutron by a nucleus bound in a free molecule can influence resonance shape and other aspects of neutron reaction cross sections. A formalism is developed for centrosymmetric molecules such as UF6 and applied to the shape of the 6.67 eV resonance in 238U. The ratio of the resonance shape for 238UF6 gas and for solid 238U3O8 has been measured and compared with the calculation. Reasonable agreement is obtained indicating the validity of the calculation and the necessity to include vibration effects to avoid large errors in measurements and calculations on gascontaining systems. NUCLEAR REACTIONS 238U(n,γ) measured at 6.67 eV resonance; Effect of molecular vibrations studied experimentally and theoretically.

  4. Vibrational-state-selected ion--molecule reaction cross sections at thermal energies

    NARCIS (Netherlands)

    Pijkeren, D. van; Boltjes, E.; Eck, J. van; Niehaus, A.

    1984-01-01

    A method designed to measure relative ion—molecule reaction rates at thermal collision energies for selected reactant ion vibrational states is described. Relative reaction rates are determined for the three endothermic reactions: H2+ (υ)(He,H)HeH+, H2+ (υ)(Ne,H)NeH+, D2+(υ)(Ne, D)NeD+, and for the

  5. Bibliography on electron collisions with molecules: rotational and vibrational excitations, 1980-2000

    International Nuclear Information System (INIS)

    Itikawa, Yukikazu

    2001-04-01

    A list of papers reporting cross sections for electron-impact excitations of rotational and vibrational states of molecules is presented. The list includes both the theoretical and the experimental papers published in 1980-2000. An index by molecular species is provided at the end of the bibliography. (author)

  6. Bonding and vibrational dynamics of a large π-conjugated molecule on a metal surface

    International Nuclear Information System (INIS)

    Temirov, R; Soubatch, S; Lassise, A; Tautz, F S

    2008-01-01

    The interplay between the substrate bonding of a large π-conjugated semiconductor molecule and the dynamical properties of the metal-organic interface is studied, employing the prototypical PTCDA/Ag(111) monolayer as an example. Both the coupling of molecular vibrations to the electron-hole-pair continuum of the metal surface and the inelastic scattering of tunnelling electrons by the molecular vibrations on their passage through the molecule are considered. The results of both types of experiment are consistent with the findings of measurements which probe the geometric and electronic structure of the adsorbate-substrate complex directly; generally speaking, they can be understood in the framework of standard theories for the electron-vibron coupling. While the experiments reported here in fact provide additional qualitative insights into the substrate bonding of our π-conjugated model molecule, their detailed quantitative understanding would require a full calculation of the dynamical interface properties, which is currently not available

  7. Energized Learning

    Science.gov (United States)

    college-level courses. The site includes lessons and activities that develop specific skills and knowledge that planning for an energy efficient future involves knowledge of science, mathematics, economics and skepticism about their predictive power. At the core of the Energized Leaning site is a interactive web-based

  8. INTERPRETATION OF INFRARED VIBRATION-ROTATION SPECTRA OF INTERSTELLAR AND CIRCUMSTELLAR MOLECULES

    International Nuclear Information System (INIS)

    Lacy, John H.

    2013-01-01

    Infrared vibration-rotation lines can be valuable probes of interstellar and circumstellar molecules, especially symmetric molecules, which have no pure rotational transitions. But most such observations have been interpreted with an isothermal absorbing slab model, which leaves out important radiative transfer and molecular excitation effects. A more realistic non-LTE and non-isothermal radiative transfer model has been constructed. The results of this model are in much better agreement with the observations, including cases where lines in one branch of a vibration-rotation band are in absorption and another in emission. In general, conclusions based on the isothermal absorbing slab model can be very misleading, but the assumption of LTE may not lead to such large errors, particularly if the radiation field temperature is close to the gas temperature.

  9. Vibrational excitation of hydrogen molecules by two-photon absorption and third-harmonic generation

    Science.gov (United States)

    Miyamoto, Yuki; Hara, Hideaki; Hiraki, Takahiro; Masuda, Takahiko; Sasao, Noboru; Uetake, Satoshi; Yoshimi, Akihiro; Yoshimura, Koji; Yoshimura, Motohiko

    2018-01-01

    We report the coherent excitation of the vibrational state of hydrogen molecules by two-photon absorption and the resultant third-harmonic generation (THG). Parahydrogen molecules cooled by liquid nitrogen are irradiated by mid-infrared nanosecond pulses at 4.8 μm with a nearly Fourier-transform-limited linewidth. The first excited vibrational state of parahydrogen is populated by two-photon absorption of the mid-infrared photons. Because of the narrow linewidth of the mid-infrared pulses, coherence between the ground and excited states is sufficient to induce higher-order processes. Near-infrared photons from the THG are observed at 1.6 μm. The dependence of the intensity of the near-infrared radiation on mid-infrared pulse energy, target pressure, and cell length is determined. We used a simple formula for THG with consideration of realistic experimental conditions to explain the observed results.

  10. Energy distribution in selected fragment vibrations in dissociation processes in polyatomic molecules

    International Nuclear Information System (INIS)

    Band, Y.B.; Freed, K.F.

    1977-01-01

    The full quantum theory of dissociation processes in polyatomic molecules is converted to a form enabling the isolation of a selected fragment vibration. This form enables the easy evaluation of the probability distribution for energy partitioning between this vibration and all other degrees of freedom that results from the sudden Franck--Condon rearrangement process. The resultant Franck--Condon factors involve the square of the one-dimensional overlap integral between effective oscillator wavefunctions and the wavefunctions for the selected fragment vibration, a form that resembles the simple golden rule model for polyatomic dissociation and reaction processes. The full quantum theory can, therefore, be viewed as providing both a rigorous justification for certain generic aspects of the simple golden rule model as well as providing a number of important generalizations thereof. Some of these involve dealing with initial bound state vibrational excitation, explicit molecule, fragment and energy dependence of the effective oscillator, and the incorporation of all isotopic dependence. In certain limiting situations the full quantum theory yields simple, readily usable analytic expressions for the frequency and equilibrium position of the effective oscillator. Specific applications are presented for the direct photodissociation of HCN, DCN, and CO 2 where comparisons between the full theory and the simple golden rule are presented. We also discuss the generalizations of the previous theory to enable the incorporation of effects of distortion in the normal modes as a function of the reaction coordinate on the repulsive potential energy surface

  11. Polyad quantum numbers and multiple resonances in anharmonic vibrational studies of polyatomic molecules.

    Science.gov (United States)

    Krasnoshchekov, Sergey V; Stepanov, Nikolay F

    2013-11-14

    In the theory of anharmonic vibrations of a polyatomic molecule, mixing the zero-order vibrational states due to cubic, quartic and higher-order terms in the potential energy expansion leads to the appearance of more-or-less isolated blocks of states (also called polyads), connected through multiple resonances. Such polyads of states can be characterized by a common secondary integer quantum number. This polyad quantum number is defined as a linear combination of the zero-order vibrational quantum numbers, attributed to normal modes, multiplied by non-negative integer polyad coefficients, which are subject to definition for any particular molecule. According to Kellman's method [J. Chem. Phys. 93, 6630 (1990)], the corresponding formalism can be conveniently described using vector algebra. In the present work, a systematic consideration of polyad quantum numbers is given in the framework of the canonical Van Vleck perturbation theory (CVPT) and its numerical-analytic operator implementation for reducing the Hamiltonian to the quasi-diagonal form, earlier developed by the authors. It is shown that CVPT provides a convenient method for the systematic identification of essential resonances and the definition of a polyad quantum number. The method presented is generally suitable for molecules of significant size and complexity, as illustrated by several examples of molecules up to six atoms. The polyad quantum number technique is very useful for assembling comprehensive basis sets for the matrix representation of the Hamiltonian after removal of all non-resonance terms by CVPT. In addition, the classification of anharmonic energy levels according to their polyad quantum numbers provides an additional means for the interpretation of observed vibrational spectra.

  12. Commutator perturbation method in the study of vibrational-rotational spectra of diatomic molecules

    International Nuclear Information System (INIS)

    Matamala-Vasquez, A.; Karwowski, J.

    2000-01-01

    The commutator perturbation method, an algebraic version of the Van Vleck-Primas perturbation method, expressed in terms of ladder operators, has been applied to solving the eigenvalue problem of the Hamiltonian describing the vibrational-rotational motion of a diatomic molecule. The physical model used in this work is based on Dunham's approach. The method facilitates obtaining both energies and eigenvectors in an algebraic way

  13. Behavior of ro-vibrationally excited H2 molecules and H atoms in a plasma expansion

    International Nuclear Information System (INIS)

    Vankan, P.; Schram, D.C.; Engeln, R.

    2005-01-01

    The behavior in a supersonic plasma expansion of H atom and H2 molecules, both ground-state and ro-vibrationally excited, is studied using various laser spectroscopic techniques. The ground-state H2 molecules expand like a normal gas. The behavior of H atoms and H 2 rv molecules, on the other hand, is considerably influenced, and to some extend even determined, by their reactivity. The H atoms diffuse out of the expansion due to surface association at the walls of the vacuum vessel. Moreover, by reducing the surface area of the nozzle by a factor of two, the amount of H atoms leaving the source is increased by one order of magnitude, due to a decreased surface association of H atoms in the nozzle. The evolution of the ro-vibrational distributions along the expansion axis shows the relaxation of the molecular hydrogen from the high temperature in the up-stream region to the low ambient temperature in the down-stream region. Whereas the vibrational distribution resembles a Boltzmann distribution, the rotational distribution is a non-equilibrium one, in which the high rotational levels (J > 7) are much more populated than what is expected from the low rotational levels (J <5). We observed overpopulations of up to seven orders of magnitude. The production of the high rotational levels is very probably connected to the surface association in the nozzle

  14. Symmetry Adaptation of the Rotation-Vibration Theory for Linear Molecules

    Directory of Open Access Journals (Sweden)

    Katy L. Chubb

    2018-04-01

    Full Text Available A numerical application of linear-molecule symmetry properties, described by the D ∞ h point group, is formulated in terms of lower-order symmetry groups D n h with finite n. Character tables and irreducible representation transformation matrices are presented for D n h groups with arbitrary n-values. These groups can subsequently be used in the construction of symmetry-adapted ro-vibrational basis functions for solving the Schrödinger equations of linear molecules. Their implementation into the symmetrisation procedure based on a set of “reduced” vibrational eigenvalue problems with simplified Hamiltonians is used as a practical example. It is shown how the solutions of these eigenvalue problems can also be extended to include the classification of basis-set functions using ℓ, the eigenvalue (in units of ℏ of the vibrational angular momentum operator L ^ z . This facilitates the symmetry adaptation of the basis set functions in terms of the irreducible representations of D n h . 12 C 2 H 2 is used as an example of a linear molecule of D ∞ h point group symmetry to illustrate the symmetrisation procedure of the variational nuclear motion program Theoretical ROVibrational Energies (TROVE.

  15. Selective excitation of a vibrational level within the electronic ground state of a polyatomic molecule with ultra pulses

    CSIR Research Space (South Africa)

    de Clercq, L

    2010-09-01

    Full Text Available Coherent control of the upper vibrational level populations in the electronic ground state of a polyatomic molecule was simulated. Results indicate that selective excitation of a specific upper state level is possible...

  16. Comparison of force fields and calculation methods for vibration intervals of isotopic H+3 molecules

    International Nuclear Information System (INIS)

    Carney, G.D.; Adler-Golden, S.M.; Lesseski, D.C.

    1986-01-01

    This paper reports (a) improved values for low-lying vibration intervals of H + 3 , H 2 D + , D 2 H + , and D + 3 calculated using the variational method and Simons--Parr--Finlan representations of the Carney--Porter and Dykstra--Swope ab initio H + 3 potential energy surfaces, (b) quartic normal coordinate force fields for isotopic H + 3 molecules, (c) comparisons of variational and second-order perturbation theory, and (d) convergence properties of the Lai--Hagstrom internal coordinate vibrational Hamiltonian. Standard deviations between experimental and ab initio fundamental vibration intervals of H + 3 , H 2 D + , D 2 H + , and D + 3 for these potential surfaces are 6.9 (Carney--Porter) and 1.2 cm -1 (Dykstra--Swope). The standard deviations between perturbation theory and exact variational fundamentals are 5 and 10 cm -1 for the respective surfaces. The internal coordinate Hamiltonian is found to be less efficient than the previously employed ''t'' coordinate Hamiltonian for these molecules, except in the case of H 2 D +

  17. Collision dynamics of methyl radicals and highly vibrationally excited molecules using crossed molecular beams

    International Nuclear Information System (INIS)

    Chu, P.M.Y.

    1991-10-01

    The vibrational to translational (V→T) energy transfer in collisions between large highly vibrationally excited polyatomics and rare gases was investigated by time-of-flight techniques. Two different methods, UV excitation followed by intemal conversion and infrared multiphoton excitation (IRMPE), were used to form vibrationally excited molecular beams of hexafluorobenzene and sulfur hexafluoride, respectively. The product translational energy was found to be independent of the vibrational excitation. These results indicate that the probability distribution function for V→T energy transfer is peaked at zero. The collisional relaxation of large polyatomic molecules with rare gases most likely occurs through a rotationally mediated process. Photodissociation of nitrobenzene in a molecular beam was studied at 266 nm. Two primary dissociation channels were identified including simple bond rupture to produce nitrogen dioxide and phenyl radical and isomerization to form nitric oxide and phenoxy radical. The time-of-flight spectra indicate that simple bond rupture and isomerization occurs via two different mechanisms. Secondary dissociation of the phenoxy radicals to carbon monoxide and cyclopentadienyl radicals was observed as well as secondary photodissociation of phenyl radical to give H atom and benzyne. A supersonic methyl radical beam source is developed. The beam source configuration and conditions were optimized for CH 3 production from the thermal decomposition of azomethane. Elastic scattering of methyl radical and neon was used to differentiate between the methyl radicals and the residual azomethane in the molecular beam

  18. Time delay for resonant vibrational excitation in electron--molecule collisions

    International Nuclear Information System (INIS)

    Gauyacq, J.P.

    1990-01-01

    An analysis of the time delay associated with vibrational excitation in electron--molecule collision is presented. It consists of a direct study of the time dependence of the process for three model systems. An electron wave packet, that is narrow in time, is sent on the target and the amplitudes in the different inelastic channels are studied as functions of time. The time delay is found to correspond to very different time effects: broadenings, shifts in time of the wave packet, but also complex distortions that cannot be represented by a time delay. The direct analysis of the scattered wave also provides new insights into the vibrational excitation process. It should be a useful tool to analyze complex collision processes

  19. DFT study of conformational and vibrational characteristics of 2-(2-hydroxyphenyl)benzothiazole molecule.

    Science.gov (United States)

    Pandey, Urmila; Srivastava, Mayuri; Singh, R P; Yadav, R A

    2014-08-14

    The conformational and IR and Raman spectral studies of 2-(2-hydroxyphenyl)benzothiazole have been carried out by using the DFT method at the B3LYP/6-311++G(**) level. The detailed vibrational assignments have been done on the basis of calculated potential energy distributions. Comparative studies of molecular geometries, atomic charges and vibrational fundamentals of all the conformers have been made. There are four possible conformers for this molecule. The optimized geometrical parameters obtained by B3LYP/6-311++G(**) method showed good agreement with the experimental X-ray data. The atomic polar tensor (APT) charges, Mulliken atomic charges, natural bond orbital (NBO) analysis and HOMO-LUMO energy gap of HBT and its conformers were also computed. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Rovibrational Interaction and Vibrational Constants of the Symmetric Top Molecule 14NF3

    Directory of Open Access Journals (Sweden)

    Hamid Najib

    2013-01-01

    Full Text Available Several accurate experimental values of the and rotation-vibration interaction parameters and , , and vibrational constants have been extracted from the most recent high-resolution Fourier transform infrared, millimeter wave, and centimeter wave investigations in the spectra of the oblate symmetric top molecule 14NF3. The band-centres used are those of the four fundamental, the overtones, the combination, and hot bands identified in the region between 400 cm−1 and 2000 cm−1. Comparison of our constants with the ones measured previously, by infrared spectroscopy at low resolution, reveals orders of magnitude higher accuracy of the new values. The agreement between our values and those determined by ab initio calculations employing the TZ2Pf basis is excellent.

  1. Can Internal Conversion BE Controlled by Mode-Specific Vibrational Excitation in Polyatomic Molecules

    Science.gov (United States)

    Portnov, Alexander; Epshtein, Michael; Bar, Ilana

    2017-06-01

    Nonadiabatic processes, dominated by dynamic passage of reactive fluxes through conical intersections (CIs) are considered to be appealing means for manipulating reaction paths. One approach that is considered to be effective in controlling the course of dissociation processes is the selective excitation of vibrational modes containing a considerable component of motion. Here, we have chosen to study the predissociation of the model test molecule, methylamine and its deuterated isotopologues, excited to well-characterized quantum states on the first excited electronic state, S_{1}, by following the N-H(D) bond fission dynamics through sensitive H(D) photofragment probing. The branching ratios between slow and fast H(D) photofragments, the internal energies of their counter radical photofragments and the anisotropy parameters for fast H photofragments, confirm correlated anomalies for predissociation initiated from specific rovibronic states, reflecting the existence of a dynamic resonance in each molecule. This resonance strongly depends on the energy of the initially excited rovibronic states, the evolving vibrational mode on the repulsive S_{1} part during N-H(D) bond elongation, and the manipulated passage through the CI that leads to radicals excited with C-N-H(D) bending and preferential perpendicular bond breaking, relative to the photolyzing laser polarization, in molecules containing the NH_{2} group. The indicated resonance plays an important role in the bifurcation dynamics at the CI and can be foreseen to exist in other photoinitiated processes and to control their outcome.

  2. Quantum dynamics study on the binding of a positron to vibrationally excited states of hydrogen cyanide molecule

    Science.gov (United States)

    Takayanagi, Toshiyuki; Suzuki, Kento; Yoshida, Takahiko; Kita, Yukiumi; Tachikawa, Masanori

    2017-05-01

    We present computational results of vibrationally enhanced positron annihilation in the e+ + HCN/DCN collisions within a local complex potential model. Vibrationally elastic and inelastic cross sections and effective annihilation rates were calculated by solving a time-dependent complex-potential Schrödinger equation under the ab initio potential energy surface for the positron attached HCN molecule, [HCN; e+], with multi-component configuration interaction level (Kita and Tachikawa, 2014). We discuss the effect of vibrational excitation on the positron affinities from the obtained vibrational resonance features.

  3. Understanding the reaction between muonium atoms and hydrogen molecules: zero point energy, tunnelling, and vibrational adiabaticity

    Science.gov (United States)

    Aldegunde, J.; Jambrina, P. G.; García, E.; Herrero, V. J.; Sáez-Rábanos, V.; Aoiz, F. J.

    2013-11-01

    The advent of very precise measurements of rate coefficients in reactions of muonium (Mu), the lightest hydrogen isotope, with H2 in its ground and first vibrational state and of kinetic isotope effects with respect to heavier isotopes has triggered a renewed interests in the field of muonic chemistry. The aim of the present article is to review the most recent results about the dynamics and mechanism of the reaction Mu+H2 to shed light on the importance of quantum effects such as tunnelling, the preservation of the zero point energy, and the vibrational adiabaticity. In addition to accurate quantum mechanical (QM) calculations, quasiclassical trajectories (QCT) have been run in order to check the reliability of this method for this isotopic variant. It has been found that the reaction with H2(v=0) is dominated by the high zero point energy (ZPE) of the products and that tunnelling is largely irrelevant. Accordingly, both QCT calculations that preserve the products' ZPE as well as those based on the Ring Polymer Molecular Dynamics methodology can reproduce the QM rate coefficients. However, when the hydrogen molecule is vibrationally excited, QCT calculations fail completely in the prediction of the huge vibrational enhancement of the reactivity. This failure is attributed to tunnelling, which plays a decisive role breaking the vibrational adiabaticity when v=1. By means of the analysis of the results, it can be concluded that the tunnelling takes place through the ν1=1 collinear barrier. Somehow, the tunnelling that is missing in the Mu+H2(v=0) reaction is found in Mu+H2(v=1).

  4. ESR measurement of the concentration of vibrationally excited hydrogen and deuterium molecules

    International Nuclear Information System (INIS)

    Gershenzon, Yu.M.; Ivanov, A.V.; Il'in, S.D.; Kucheryavyi, S.I.; Rozenshtein, V.B.

    1988-01-01

    A method is described for measuring the concentration of vibrationally excited H 2 and D 2 molecules using an ESR microwave spectrometer. The essence of the method is the titration of H 2 (v = 1) and D 2 (v = 1) with D and H atoms and measurement of the concentrations of the titration products H and D, respectively. Stoichiometric titration coefficients were determined in the form of proportionality coefficients between the titration signals Δ[H], Δ[D] and the concentrations of H 2 (v = 1), D 2 (v = 1)

  5. Communication: atomic force detection of single-molecule nonlinear optical vibrational spectroscopy.

    Science.gov (United States)

    Saurabh, Prasoon; Mukamel, Shaul

    2014-04-28

    Atomic Force Microscopy (AFM) allows for a highly sensitive detection of spectroscopic signals. This has been first demonstrated for NMR of a single molecule and recently extended to stimulated Raman in the optical regime. We theoretically investigate the use of optical forces to detect time and frequency domain nonlinear optical signals. We show that, with proper phase matching, the AFM-detected signals closely resemble coherent heterodyne-detected signals. Applications are made to AFM-detected and heterodyne-detected vibrational resonances in Coherent Anti-Stokes Raman Spectroscopy (χ((3))) and sum or difference frequency generation (χ((2))).

  6. Effect of vibrational excitation on the dynamics of ion-molecule reactions

    International Nuclear Information System (INIS)

    Anderson, S.L.

    1981-11-01

    A new experimental technique for the study of vibrational effects on ion-molecule reaction cross sections is described. Vibrational and collision energy dependent cross sections are presented for proton and H atom transfer, charge transfer and collision induced dissociation reactions in various isotopic H 2 + + H 2 systems. Charge and proton transfer cross sections are presented for the reactions of H 2 + and D 2 + with Ar, N 2 , CO, and O 2 . All the reactions are shown to be highly influenced by avoided crossings between the ground and first excited potential energy surfaces. Because of the nature of the crossings, vibrational motion of the systems can cause both adiabatic and non-adiabatic behavior of the system. This makes the vibrational dependences of the various cross sections a very sensitive probe of the dynamics of the collisions particularly, their behavior in the region of the crossings. Evidence is seen for charge transfer between reagents as they approach each other, transition to and in some cases reactions on excited potential energy surfaces, competition between different channels, and strong coupling of proton and charge transfer channels which occurs only for two of the systems studied (H 2 + + Ar, N 2 ). Oscillatory structure is observed in the collision energy dependence of the endoergic H 2 + (v = 0) + Ar charge transfer reaction for the first time, and a simple model which is commonly used for atom-atom charge transfer is used to fit the peaks. Finally a simple model is used to assess the importance of energy resonance and Franck-Condon effects on molecular charge transfer

  7. Influence of vibrations and rotations of diatomic molecules on their physical properties: II. Refractive index, reactivity and diffusion coefficients

    International Nuclear Information System (INIS)

    Sharipov, Alexander S; Loukhovitski, Boris I; Starik, Alexander M

    2016-01-01

    The influence of the excitation of vibrational and rotational states of diatomic molecules (H 2 , N 2 , O 2 , NO, OH, CO, CH, HF and HCl) on refractive index, reactivity and transport coefficients was analyzed by using ab initio calculated data on the effective state-specific dipole moment and static polarizability obtained in the preceding paper of the present series. It has been revealed that, for non-polar molecules, the excitation both of vibrational and rotational degrees of freedom increases the averaged polarizability and, as a consequence, the refractive index. Meanwhile, for polar molecules, the effect of molecule excitation is more complex: it can either increase or decrease the refractive index. It was also shown that the excitation of molecules slightly influences the rate constants of barrierless chemical reactions between neutral particles; whereas, for ion–molecule reactions, this effect can be more pronounced. Analysis of the variation of diffusion coefficients, taking into account the effect of molecule excitation both on the collision diameter and on the well depth of intermolecular potential, exhibited that, for non-polar molecules, the effect associated with the change of collision diameter prevails. However, for polar molecules, the effect of the excitation of vibrational states on the well depth of intermolecular potential can compensate or even exceed the decrease of diffusion coefficient due to the averaged collision diameter rise. (paper)

  8. Explicit Consideration of Water Molecules to Study Vibrational Circular DICHROÎSM of Monosaccharide's

    Science.gov (United States)

    Moussi, Sofiane; Ouamerali, Ourida

    2014-06-01

    Carbohydrates have multiples roles in biological systems. It has been found that the glycoside bond is fundamentally important in many aspects of chemistry and biology and forms the basis of carbohydrate chemistry. That means the stereochemical information, namely, glycosidic linkages α or β, gives an significant features of the carbohydrate glycosidation position of the glycosylic acceptor. For these reasons, much effort was made for the synthesis and analysis of the glycoside bond. Vibrational circular dichroism VCD has some advantages over conventional electronic circular dichroism (ECD) due to the applicability to all organic molecules and the reliability of ab initio quantum calculation. However, for a molecule with many chiral centers such as carbohydrates, determination of the absolute configuration tends to be difficult because the information from each stereochemical center is mixed and averaged over the spectrum. In the CH stretching region, only two VCD studies on carbohydrates have been reported and spectra--structure correlation, as determined for the glycoside band, remains to be investigated. T. Taniguchi and collaborators report that methyl glycosides exhibit a characteristic VCD peak, the sign of which solely reflects the C-1 absolute configuration. This work is a theoretical contribution to study the behaviour of VCD spectrum's of the monosaccharides when the water molecules are taken explicitly. This study is focused on six different monosaccharides in theirs absolute configuration R and S. We used the method of density functional theory DFT by means of the B3LYP hybrid functional and 6-31G * basis set.

  9. Effects of temperature and other experimental variables on single molecule vibrational spectroscopy with the scanning tunneling microscope

    International Nuclear Information System (INIS)

    Lauhon, L. J.; Ho, W.

    2001-01-01

    Inelastic electron tunneling spectroscopy (IETS) was performed on single molecules with a variable temperature scanning tunneling microscope. The peak intensity, width, position, and line shape of single molecule vibrational spectra were studied as a function of temperature, modulation bias, bias polarity, and tip position for the (C--H,C--D) stretching vibration of acetylene (C 2 H 2 ,C 2 D 2 ) on Cu(001). The temperature broadening of vibrational peaks was found to be a consequence of Fermi smearing as in macroscopic IETS. The modulation broadening of vibrational peaks assumed the expected form for IETS. Extrapolation of the peak width to zero temperature and modulation suggested an intrinsic width of ∼4 meV due primarily to instrumental broadening. The inelastic tunneling cross section at negative bias was reduced by a factor of 1.7 for the C--H stretch mode. Low energy modes of other molecules did not show such a reduction. There was no evidence of a tip-induced Stark shift in the peak positions. The spatial variation of the inelastic signal was measured to determine the junction stability necessary for the acquisition of single molecule vibrational spectra

  10. Microencapsulation of a hydrophilic model molecule through vibration nozzle and emulsion phase inversion technologies.

    Science.gov (United States)

    Dorati, Rossella; Genta, Ida; Modena, Tiziana; Conti, Bice

    2013-01-01

    The goal of the present work was to evaluate and discuss vibration nozzle microencapsulation (VNM) technology combined to lyophilization, for the microencapsulation of a hydrophilic model molecule into a hydrophilic polymer. Fluorescein-loaded alginate microparticles prepared by VNM and emulsion phase inversion microencapsulation (EPIM) were lyophilized. Morphology, particle size distribution, lyophilized microspheres stability upon rehydration, drug loading and in vitro release were evaluated. Well-formed microspheres were obtained by the VNM technique, with higher yields of production (93.3-100%) and smaller particle size (d50138.10-158.00) than the EPIM microspheres. Rehydration upon lyophilization occurred in 30 min maintaining microsphere physical integrity. Fluorescein release was always faster from the microspheres obtained by VNM (364 h) than from those obtained by EPIM (504 h). The results suggest that VNM is a simple, easy to be scaled-up process suitable for the microencapsulation hydrophilic drugs.

  11. Ozone kinetics in low-pressure discharges: vibrationally excited ozone and molecule formation on surfaces

    Science.gov (United States)

    Marinov, Daniil; Guerra, Vasco; Guaitella, Olivier; Booth, Jean-Paul; Rousseau, Antoine

    2013-10-01

    A combined experimental and modeling investigation of the ozone kinetics in the afterglow of pulsed direct current discharges in oxygen is carried out. The discharge is generated in a cylindrical silica tube of radius 1 cm, with short pulse durations between 0.5 and 2 ms, pressures in the range 1-5 Torr and discharge currents ˜40-120 mA. Time-resolved absolute concentrations of ground-state atoms and ozone molecules were measured simultaneously in situ, by two-photon absorption laser-induced fluorescence and ultraviolet absorption, respectively. The experiments were complemented by a self-consistent model developed to interpret the results and, in particular, to evaluate the roles of vibrationally excited ozone and of ozone formation on surfaces. It is found that vibrationally excited ozone, O_3^{*} , plays an important role in the ozone kinetics, leading to a decrease in the ozone concentration and an increase in its formation time. In turn, the kinetics of O_3^{*} is strongly coupled with those of atomic oxygen and O2(a 1Δg) metastables. Ozone formation at the wall does not contribute significantly to the total ozone production under the present conditions. Upper limits for the effective heterogeneous recombination probability of O atoms into ozone are established.

  12. Ozone kinetics in low-pressure discharges: vibrationally excited ozone and molecule formation on surfaces

    International Nuclear Information System (INIS)

    Marinov, Daniil; Guaitella, Olivier; Booth, Jean-Paul; Rousseau, Antoine; Guerra, Vasco

    2013-01-01

    A combined experimental and modeling investigation of the ozone kinetics in the afterglow of pulsed direct current discharges in oxygen is carried out. The discharge is generated in a cylindrical silica tube of radius 1 cm, with short pulse durations between 0.5 and 2 ms, pressures in the range 1–5 Torr and discharge currents ∼40–120 mA. Time-resolved absolute concentrations of ground-state atoms and ozone molecules were measured simultaneously in situ, by two-photon absorption laser-induced fluorescence and ultraviolet absorption, respectively. The experiments were complemented by a self-consistent model developed to interpret the results and, in particular, to evaluate the roles of vibrationally excited ozone and of ozone formation on surfaces. It is found that vibrationally excited ozone, O 3 * , plays an important role in the ozone kinetics, leading to a decrease in the ozone concentration and an increase in its formation time. In turn, the kinetics of O 3 * is strongly coupled with those of atomic oxygen and O 2 (a 1 Δ g ) metastables. Ozone formation at the wall does not contribute significantly to the total ozone production under the present conditions. Upper limits for the effective heterogeneous recombination probability of O atoms into ozone are established. (paper)

  13. S-matrix analysis of vibrational and alignment effects in intense-field multiphoton ionization of molecules

    Energy Technology Data Exchange (ETDEWEB)

    Requate, A

    2007-03-15

    Theoretical analysis of the vibrational excitation of small molecules during multiphoton ionization in intense laser fields of optical and infrared frequencies. Analysis of the alignment dependence of the electron impact ionization of diatomic molecules in the presence of an intense laser field as the final step in the process of Nonsequential Double Ionization. Quantum mechanical description using S-matrix theory in Strong Field Approximation (SFA), i.e. beyond perturbation theory. (orig.)

  14. S-matrix analysis of vibrational and alignment effects in intense-field multiphoton ionization of molecules

    International Nuclear Information System (INIS)

    Requate, A.

    2007-03-01

    Theoretical analysis of the vibrational excitation of small molecules during multiphoton ionization in intense laser fields of optical and infrared frequencies. Analysis of the alignment dependence of the electron impact ionization of diatomic molecules in the presence of an intense laser field as the final step in the process of Nonsequential Double Ionization. Quantum mechanical description using S-matrix theory in Strong Field Approximation (SFA), i.e. beyond perturbation theory. (orig.)

  15. Resummation of divergent perturbation series: Application to the vibrational states of H2CO molecule.

    Science.gov (United States)

    Duchko, A N; Bykov, A D

    2015-10-21

    Large-order Rayleigh-Schrödinger perturbation theory (RSPT) is applied to the calculation of anharmonic vibrational energy levels of H2CO molecule. We use the model of harmonic oscillators perturbed by anharmonic terms of potential energy. Since the perturbation series typically diverge due to strong couplings, we apply the algebraic approximation technique because of its effectiveness shown earlier by Goodson and Sergeev [J. Chem. Phys. 110, 8205 (1999); ibid. 124, 094111 (2006)] and in our previous articles [A. D. Bykov et al. Opt. Spectrosc. 114, 396 (2013); ibid. 116, 598 (2014)]. To facilitate the resummation of terms contributing to perturbed states, when resonance mixing between states is especially strong and perturbation series diverge very quick, we used repartition of the Hamiltonian by shifting the normal mode frequencies. Energy levels obtained by algebraic approximants were compared with the results of variational calculation. It was found that for low energy states (up to ∼5000 cm(-1)), algebraic approximants gave accurate values of energy levels, which were in excellent agreement with the variational method. For highly excited states, strong and multiple resonances complicate series resummation, but a suitable change of normal mode frequencies allows one to reduce the resonance mixing and to get accurate energy levels. The theoretical background of the problem of RSPT series divergence is discussed along with its numerical analysis. For these purposes, the vibrational energy is considered as a function of a complex perturbation parameter. Layout and classification of its singularities allow us to model the asymptotic behavior of the perturbation series and prove the robustness of the algorithm.

  16. Resummation of divergent perturbation series: Application to the vibrational states of H2CO molecule

    International Nuclear Information System (INIS)

    Duchko, A. N.; Bykov, A. D.

    2015-01-01

    Large-order Rayleigh–Schrödinger perturbation theory (RSPT) is applied to the calculation of anharmonic vibrational energy levels of H 2 CO molecule. We use the model of harmonic oscillators perturbed by anharmonic terms of potential energy. Since the perturbation series typically diverge due to strong couplings, we apply the algebraic approximation technique because of its effectiveness shown earlier by Goodson and Sergeev [J. Chem. Phys. 110, 8205 (1999); ibid. 124, 094111 (2006)] and in our previous articles [A. D. Bykov et al. Opt. Spectrosc. 114, 396 (2013); ibid. 116, 598 (2014)]. To facilitate the resummation of terms contributing to perturbed states, when resonance mixing between states is especially strong and perturbation series diverge very quick, we used repartition of the Hamiltonian by shifting the normal mode frequencies. Energy levels obtained by algebraic approximants were compared with the results of variational calculation. It was found that for low energy states (up to ∼5000 cm −1 ), algebraic approximants gave accurate values of energy levels, which were in excellent agreement with the variational method. For highly excited states, strong and multiple resonances complicate series resummation, but a suitable change of normal mode frequencies allows one to reduce the resonance mixing and to get accurate energy levels. The theoretical background of the problem of RSPT series divergence is discussed along with its numerical analysis. For these purposes, the vibrational energy is considered as a function of a complex perturbation parameter. Layout and classification of its singularities allow us to model the asymptotic behavior of the perturbation series and prove the robustness of the algorithm

  17. Vibrational relaxation dynamics of SD molecules in As2S3: Observation of an anomalous isotope effect

    International Nuclear Information System (INIS)

    Engholm, J.R.; Happek, U.; Rella, C.W.

    1995-01-01

    It is generally assumed that the vibrational relaxation of molecular impurities in crystals and glasses mainly depends on the order of the decay process, with lower order processes leading to more rapid relaxation (a behavior that is known under the term open-quotes gap-lawclose quotes). Here we present measurements that contradict this assumption. Using high intensity psec pulses of the Stanford FEL we measured the relaxation rate of the SD vibrational stretch mode (at a frequency of 1800 cm) by applying a pump-probe technique. We find relaxation rates on the order of 2x10 9 sec -1 , which are a factor of 2 lower than those found for the isotope molecule SH (at a frequency of about 2500 cm - 1 ) in the same host 1 . We recall that the relaxation of the SD vibrational stretch mode is controlled by a lower order process as compared to the SH molecule, which is due to the smaller number of host vibrational quanta to match the energy of the stretch mode; a fact we have confirmed experimentally by temperature dependent relaxation measurements. Thus our remits are in marked contrast to the so-called open-quotes Gap-Lawclose quotes and emphasize the importance of the molecule - host coupling in the relaxation dynamics

  18. The effect of the condensed-phase environment on the vibrational frequency shift of a hydrogen molecule inside clathrate hydrates.

    Science.gov (United States)

    Powers, Anna; Scribano, Yohann; Lauvergnat, David; Mebe, Elsy; Benoit, David M; Bačić, Zlatko

    2018-04-14

    We report a theoretical study of the frequency shift (redshift) of the stretching fundamental transition of an H 2 molecule confined inside the small dodecahedral cage of the structure II clathrate hydrate and its dependence on the condensed-phase environment. In order to determine how much the hydrate water molecules beyond the confining small cage contribute to the vibrational frequency shift, quantum five-dimensional (5D) calculations of the coupled translation-rotation eigenstates are performed for H 2 in the v=0 and v=1 vibrational states inside spherical clathrate hydrate domains of increasing radius and a growing number of water molecules, ranging from 20 for the isolated small cage to over 1900. In these calculations, both H 2 and the water domains are treated as rigid. The 5D intermolecular potential energy surface (PES) of H 2 inside a hydrate domain is assumed to be pairwise additive. The H 2 -H 2 O pair interaction, represented by the 5D (rigid monomer) PES that depends on the vibrational state of H 2 , v=0 or v=1, is derived from the high-quality ab initio full-dimensional (9D) PES of the H 2 -H 2 O complex [P. Valiron et al., J. Chem. Phys. 129, 134306 (2008)]. The H 2 vibrational frequency shift calculated for the largest clathrate domain considered, which mimics the condensed-phase environment, is about 10% larger in magnitude than that obtained by taking into account only the small cage. The calculated splittings of the translational fundamental of H 2 change very little with the domain size, unlike the H 2 j = 1 rotational splittings that decrease significantly as the domain size increases. The changes in both the vibrational frequency shift and the j = 1 rotational splitting due to the condensed-phase effects arise predominantly from the H 2 O molecules in the first three complete hydration shells around H 2 .

  19. The effect of the condensed-phase environment on the vibrational frequency shift of a hydrogen molecule inside clathrate hydrates

    Science.gov (United States)

    Powers, Anna; Scribano, Yohann; Lauvergnat, David; Mebe, Elsy; Benoit, David M.; Bačić, Zlatko

    2018-04-01

    We report a theoretical study of the frequency shift (redshift) of the stretching fundamental transition of an H2 molecule confined inside the small dodecahedral cage of the structure II clathrate hydrate and its dependence on the condensed-phase environment. In order to determine how much the hydrate water molecules beyond the confining small cage contribute to the vibrational frequency shift, quantum five-dimensional (5D) calculations of the coupled translation-rotation eigenstates are performed for H2 in the v =0 and v =1 vibrational states inside spherical clathrate hydrate domains of increasing radius and a growing number of water molecules, ranging from 20 for the isolated small cage to over 1900. In these calculations, both H2 and the water domains are treated as rigid. The 5D intermolecular potential energy surface (PES) of H2 inside a hydrate domain is assumed to be pairwise additive. The H2-H2O pair interaction, represented by the 5D (rigid monomer) PES that depends on the vibrational state of H2, v =0 or v =1 , is derived from the high-quality ab initio full-dimensional (9D) PES of the H2-H2O complex [P. Valiron et al., J. Chem. Phys. 129, 134306 (2008)]. The H2 vibrational frequency shift calculated for the largest clathrate domain considered, which mimics the condensed-phase environment, is about 10% larger in magnitude than that obtained by taking into account only the small cage. The calculated splittings of the translational fundamental of H2 change very little with the domain size, unlike the H2 j = 1 rotational splittings that decrease significantly as the domain size increases. The changes in both the vibrational frequency shift and the j = 1 rotational splitting due to the condensed-phase effects arise predominantly from the H2O molecules in the first three complete hydration shells around H2.

  20. Nonadiabatic effects on surfaces: Kohn anomaly, electronic damping of adsorbate vibrations, and local heating of single molecules

    International Nuclear Information System (INIS)

    Kroeger, J

    2008-01-01

    Three aspects of electron-phonon coupling at metal surfaces are reviewed. One aspect is the Kohn effect, which describes an anomalous dispersion relation of surface phonons due to quasi-one-dimensional nesting of Fermi surface contours. The combination of electron energy loss spectroscopy and angle-resolved photoelectron spectroscopy allows us to unambiguously characterize Kohn anomaly systems. A second aspect is the nonadiabatic damping of adsorbate vibrations. Characteristic spectroscopic line shapes of vibrational modes allow us to estimate the amount of energy transfer between the vibrational mode and electron-hole pairs. Case studies of a Kohn anomaly and nonadiabatic damping are provided by the hydrogen- and deuterium-covered Mo(110) surface. As a third aspect of interaction between electrons and phonons, local heating of a C 60 molecule adsorbed on Cu(100) and in contact with the tip of a scanning tunnelling microscope is covered

  1. Direct observation of Young’s double-slit interferences in vibrationally resolved photoionization of diatomic molecules

    Science.gov (United States)

    Canton, Sophie E.; Plésiat, Etienne; Bozek, John D.; Rude, Bruce S.; Decleva, Piero; Martín, Fernando

    2011-01-01

    Vibrationally resolved valence-shell photoionization spectra of H2, N2 and CO have been measured in the photon energy range 20–300 eV using third-generation synchrotron radiation. Young’s double-slit interferences lead to oscillations in the corresponding vibrational ratios, showing that the molecules behave as two-center electron-wave emitters and that the associated interferences leave their trace in the angle-integrated photoionization cross section. In contrast to previous work, the oscillations are directly observable in the experiment, thereby removing any possible ambiguity related to the introduction of external parameters or fitting functions. A straightforward extension of an original idea proposed by Cohen and Fano [Cohen HD, Fano U (1966) Phys Rev 150:30] confirms this interpretation and shows that it is also valid for diatomic heteronuclear molecules. Results of accurate theoretical calculations are in excellent agreement with the experimental findings.

  2. Dissociative electron attachment to vibrationally excited H2 molecules involving the 2Σg+ resonant Rydberg electronic state

    International Nuclear Information System (INIS)

    Celiberto, R.; Janev, R.K.; Wadehra, J.M.; Tennyson, J.

    2012-01-01

    Graphical abstract: Dissociative electron attachment cross sections as a function of the incident electron energy and for the initial vibration levels v i = 0–5, 10 of the H 2 molecule. Highlights: ► We calculated electron–hydrogen dissociative attachment cross sections and rates coefficients. ► Collision processes occurring through a resonant Rydberg state are considered. ► Cross sections and rates were obtained for vibrationally excited hydrogen molecules. ► The cross sections exhibit pronounced oscillatory structures. ► A comparison with the process involving the electron–hydrogen resonant ground state is discussed. - Abstract: Dissociative electron attachment cross sections (DEA) on vibrationally excited H 2 molecule taking place via the 2 Σ g + Rydberg-excited resonant state are studied using the local complex potential (LCP) model for resonant collisions. The cross sections are calculated for all initial vibrational levels (v i = 0–14) of the neutral molecule. In contrast to the previously noted dramatic increase in the DEA cross sections with increasing v i , when the process proceeds via the X 2 Σ u + shape resonance of H 2 , for the 2 Σ g + Rydberg resonance the cross sections increase only gradually up to v i = 3 and then decrease. Moreover, the cross sections for v i ⩾ 6 exhibit pronounced oscillatory structures. A discussion of the origin of the observed behavior of calculated cross sections is given. The DEA rate coefficients for all v i levels are also calculated in the 0.5–1000 eV temperature range.

  3. Approximative Krieger-Nelkin orientation averaging and anisotropy of water molecules vibrations; Aproksimativno Krieger-Nelkinovo orijentacijsko usrednjenje i anozotropija vibracija molekula lake vode

    Energy Technology Data Exchange (ETDEWEB)

    Markovic, M I [Elektrothenicki fakultet, Belgrade (Yugoslavia)

    1974-07-01

    Quantum-mechanics approach of water molecules dynamics should be taken into account for precise theoretical calculation of differential scattering cross sections of neutrons. Krieger and Nelkin have proposed an approximate method for averaging orientation of molecules regarding directions of incoming and scattered neutron. This paper shows that this approach can be successfully applied for general shape of water molecule vibration anisotropy.

  4. Systematic studies of molecular vibrational anharmonicity and vibration-rotation interaction by self-consistent-field higher derivative methods: Applications to asymmetric and symmetric top and linear polyatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Clabo, D.A. Jr.

    1987-04-01

    Inclusion of the anharmonicity normal mode vibrations (i.e., the third and fourth (and higher) derivatives of a molecular Born-Oppenheimer potential energy surface) is necessary in order to theoretically reproduce experimental fundamental vibrational frequencies of a molecule. Although ab initio determinations of harmonic vibrational frequencies may give errors of only a few percent by the inclusion of electron correlation within a large basis set for small molecules, in general, molecular fundamental vibrational frequencies are more often available from high resolution vibration-rotation spectra. Recently developed analytic third derivatives methods for self-consistent-field (SCF) wavefunctions have made it possible to examine with previously unavailable accuracy and computational efficiency the anharmonic force fields of small molecules.

  5. Systematic studies of molecular vibrational anharmonicity and vibration-rotation interaction by self-consistent-field higher derivative methods: Applications to asymmetric and symmetric top and linear polyatomic molecules

    International Nuclear Information System (INIS)

    Clabo, D.A. Jr.

    1987-04-01

    Inclusion of the anharmonicity normal mode vibrations [i.e., the third and fourth (and higher) derivatives of a molecular Born-Oppenheimer potential energy surface] is necessary in order to theoretically reproduce experimental fundamental vibrational frequencies of a molecule. Although ab initio determinations of harmonic vibrational frequencies may give errors of only a few percent by the inclusion of electron correlation within a large basis set for small molecules, in general, molecular fundamental vibrational frequencies are more often available from high resolution vibration-rotation spectra. Recently developed analytic third derivatives methods for self-consistent-field (SCF) wavefunctions have made it possible to examine with previously unavailable accuracy and computational efficiency the anharmonic force fields of small molecules

  6. High resolution spectroscopy on adsorbed molecules on a Ni (110)-surface: vibrational states and electronic levels

    International Nuclear Information System (INIS)

    Kardinal, I.

    1998-01-01

    The complementary techniques of HR-XPS and HREELS have been applied to two distinct problems. The first studies adsorption and dissociation of C 2 N 2 on Ni (110) at room temperature (RT) and at 90 K and its co-adsorption with CO. At RT C 2 N 2 dissociates and forms a c(2x2)-CN structure. The resulting CN is found to be bound in the grooves of the (110) surface yielding the lowest C-N vibrational energy yet observed. C 2 N 2 was found to dissociate even at 90 K however the resulting CN overlayer after warming to RT showed remarkable differences to that of the RT adsorption. As well as the in-groove species a number of adsorption sites on the ridges with a bond order higher have been identified. Preadsorbed CO is completely driven of the Ni (110) surface by co-adsorption of CN at RT. HREELS indicates that first CO is desorbed from the on-top-sites and then from the bridge-sites of the (110)-ridges involving a considerable increase of the HREELS cross section for the CO on the bridge-sites. Also the signal intensity of the coadsorbed CN is suppressed by the CO present on the surface. The second study investigated the adsorption of bithiophene (BiT) on clean Ni (110) and the S-modified c(2x2)-S-Ni (110) and p(4x1)-S-Ni (110). The latter provided a strongly structured substrate which forced the assembly of the adsorbed BiT-molecules. The high degree of order of this adsorbate/substrate system was obvious in both the HR-XPS results and the BREELS results with strong azimuthal anisotropy. This system was used to asses the ability to use the HREELS impact selection rules to determine molecular orientation of a reasonably complex adsorbate overlayer. (author)

  7. Positron-attachment to small molecules: Vibrational enhancement of positron affinities with configuration interaction level of multi-component molecular orbital approach

    Energy Technology Data Exchange (ETDEWEB)

    Tachikawa, Masanori [Quantum Chemistry Division, Graduate School of NanoBioScience, Yokohama City University, 22-2 Seto, Kanazawa, Yokohama 236-0027 (Japan)

    2015-12-31

    To theoretically demonstrate the binding of a positron to small polarized molecules, we have calculated the vibrational averaged positron affinity (PA) values along the local vibrational contribution with the configuration interaction level of multi-component molecular orbital method. This method can take the electron-positron correlation contribution into account through single electronic - single positronic excitation configurations. The PA values are enhanced by including the local vibrational contribution from vertical PA values due to the anharmonicity of the potential.

  8. Expansion Hamiltonian model for a diatomic molecule adsorbed on a surface: Vibrational states of the CO/Cu(100) system including surface vibrations

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qingyong, E-mail: mengqingyong@dicp.ac.cn [State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, 116023 Dalian (China); Meyer, Hans-Dieter, E-mail: hans-dieter.meyer@pci.uni-heidelberg.de [Theoretische Chemie, Physikalisch-Chemisches Institut, Ruprecht-Karls Universität Heidelberg, Im Neuenheimer Feld 229, D-69120 Heidelberg (Germany)

    2015-10-28

    Molecular-surface studies are often done by assuming a corrugated, static (i.e., rigid) surface. To be able to investigate the effects that vibrations of surface atoms may have on spectra and cross sections, an expansion Hamiltonian model is proposed on the basis of the recently reported [R. Marquardt et al., J. Chem. Phys. 132, 074108 (2010)] SAP potential energy surface (PES), which was built for the CO/Cu(100) system with a rigid surface. In contrast to other molecule-surface coupling models, such as the modified surface oscillator model, the coupling between the adsorbed molecule and the surface atoms is already included in the present expansion SAP-PES model, in which a Taylor expansion around the equilibrium positions of the surface atoms is performed. To test the quality of the Taylor expansion, a direct model, that is avoiding the expansion, is also studied. The latter, however, requests that there is only one movable surface atom included. On the basis of the present expansion and direct models, the effects of a moving top copper atom (the one to which CO is bound) on the energy levels of a bound CO/Cu(100) system are studied. For this purpose, the multiconfiguration time-dependent Hartree calculations are carried out to obtain the vibrational fundamentals and overtones of the CO/Cu(100) system including a movable top copper atom. In order to interpret the results, a simple model consisting of two coupled harmonic oscillators is introduced. From these calculations, the vibrational levels of the CO/Cu(100) system as function of the frequency of the top copper atom are discussed.

  9. Vibrational Relaxation of Ground-State Oxygen Molecules With Atomic Oxygen and Carbon Dioxide

    Science.gov (United States)

    Saran, D. V.; Pejakovic, D. A.; Copeland, R. A.

    2008-12-01

    Vertical water vapor profiles are key to understanding the composition and energy budget in the mesosphere and lower thermosphere (MLT). The SABER instrument onboard NASA's TIMED satellite measures such profiles by detecting H2O(ν2) emission in the 6.8 μm region. Collisional deactivation of vibrationally excited O2, O2(X3Σ-g, υ = 1) + H2O ↔ O2(X3Σ-g, υ = 0) + H2O(ν2), is an important source of H2O(ν2). A recent study has identified two other processes involving excited O2 that control H2O(ν2) population in the MLT: (1) the vibrational-translational (V-T) relaxation of O2(X3Σ-g, υ = 1) level by atomic oxygen and (2) the V-V exchange between CO2 and excited O2 molecules [1]. Over the past few years SRI researchers have measured the atomic oxygen removal process mentioned above at room temperature [2] and 240 K [3]. These measurements have been incorporated into the models for H2O(ν2) emission [1]. Here we report laboratory studies of the collisional removal of O2(X3Σ-g, υ = 1) by O(3P) at room temperature and below, reaching temperatures relevant to mesopause and polar summer MLT (~150 K). Instead of directly detecting the O2(X3Σ-g, υ = 1) population, a technically simpler approach is used in which the υ = 1 level of the O2(a1Δg) state is monitored. A two-laser method is employed, in which the pulsed output of the first laser near 285 nm photodissociates ozone to produce atomic oxygen and O2(a1Δg, υ = 1), and the pulsed output of the second laser detects O2(a1Δg, υ = 1) via resonance-enhanced multiphoton ionization. With ground-state O2 present, owing to the rapid equilibration of the O2(X3Σ-g, υ = 1) and O2(a1Δg, υ = 1) populations via the processes O2(a1Δg, υ = 1) + O2(X3Σ-g, υ = 0) ↔ O2(a1Δg, υ = 0) + O2(X3Σ-g, υ = 1), the information on the O2(X3Σ-g, υ = 1) kinetics is extracted from the O2(a1Δg, υ = 1) temporal evolution. In addition, measurements of the removal of O2(X3Σ-g, υ = 1) by CO2 at room temperature will also

  10. Effect of collision energy and vibrational excitation on endothermic ion-molecule reactions

    International Nuclear Information System (INIS)

    Turner, T.P.

    1984-07-01

    This thesis is divided into two major parts. In the first part an experimental study of proton and deuteron transfer in H 2 + + He and HD + + He has been carried out as a function of kinetic and vibrational energy. The data gives evidence that at lower kinetic energies, the spectator stripping mechanism indeed plays an important role when H 2 + or HD + is vibrationally excited. The second half of this thesis examines the relative efficiencies between the excitation of C-C stretching vibration and collision energy on the promotion of the H atom transfer reaction of C 2 H 2 + + H 2 → C 2 H 3 + + H

  11. Structural and vibrational study of a neurotransmitter molecule: Dopamine [4-(2-aminoethyl) benzene-1,2-diol].

    Science.gov (United States)

    Jha, Omkant; Yadav, T K; Yadav, R A

    2018-01-15

    Structural and vibrational studies for the most stable conformer of dopamine {4-(2-Aminoethyl) benzene-1, 2-diol} have been carried out at the DFT/B3LYP/6-311++G** level using the Gaussian 09 software. The IR and Raman spectra have been recorded and analyzed in light of the computed vibrational parameters using the DFT and the PEDs computed with the help of the GAR2PED software. Some of the fundamentals have considerably changed frequencies in going from benzene to dopamine. Except the rocking and wagging modes of the NH 2 group the other four modes are pure group modes. The rocking and wagging modes of the NH 2 group show mixing with the other modes. The two OH stretching vibrations are highly localized modes. The Kekule phenyl ring stretching mode is found to remain almost unchanged. The HOMO-LUMO study suggests the existence of charge transfer within the molecule and the energy gap supports the pharmacological active property of the dopamine molecule. The NBO analysis has been carried out to understand the proper and improper hydrogen bonding. Copyright © 2017. Published by Elsevier B.V.

  12. Large Amplitude Motions in Polyatomic Molecule Spectra: Intramolecular Vibrational Redistribution and Isomerization

    National Research Council Canada - National Science Library

    Field, Robert

    1997-01-01

    Through Stimulated Emission Pumping (SEP) studies of highly excited vibrational levels of the electronic ground state of HCP, the spectroscopic signatures of bond breaking isomer/atom (HCP right arrow HPC...

  13. Vibrationally induced inversion of photoelectron forward-backward asymmetry in chiral molecule photoionization by circularly polarized light

    Science.gov (United States)

    Garcia, Gustavo A.; Nahon, Laurent; Daly, Steven; Powis, Ivan

    2013-01-01

    Electron–nuclei coupling accompanying excitation and relaxation processes is a fascinating phenomenon in molecular dynamics. A striking and unexpected example of such coupling is presented here in the context of photoelectron circular dichroism measurements on randomly oriented, chiral methyloxirane molecules, unaffected by any continuum resonance. Here, we report that the forward-backward asymmetry in the electron angular distribution, with respect to the photon axis, which is associated with photoelectron circular dichroism can surprisingly reverse direction according to the ion vibrational mode excited. This vibrational dependence represents a clear breakdown of the usual Franck–Condon assumption, ascribed to the enhanced sensitivity of photoelectron circular dichroism (compared with other observables like cross-sections or the conventional anisotropy parameter-β) to the scattering phase off the chiral molecular potential, inducing a dependence on the nuclear geometry sampled in the photoionization process. Important consequences for the interpretation of such dichroism measurements within analytical contexts are discussed. PMID:23828557

  14. Do vibrationally excited OH molecules affect middle and upper atmospheric chemistry?

    Directory of Open Access Journals (Sweden)

    T. von Clarmann

    2010-10-01

    Full Text Available Except for a few reactions involving electronically excited molecular or atomic oxygen or nitrogen, atmospheric chemistry modelling usually assumes that the temperature dependence of reaction rates is characterized by Arrhenius' law involving kinetic temperatures. It is known, however, that in the upper atmosphere the vibrational temperatures may exceed the kinetic temperatures by several hundreds of Kelvins. This excess energy has an impact on the reaction rates. We have used upper atmospheric OH populations and reaction rate coefficients for OH(v=0...9+O3 and OH(v=0...9+O to estimate the effective (i.e. population weighted reaction rates for various atmospheric conditions. We have found that the effective rate coefficient for OH(v=0...9+O3 can be larger by a factor of up to 1470 than that involving OH in its vibrational ground state only. At altitudes where vibrationally excited states of OH are highly populated, the OH reaction is a minor sink of Ox and O3 compared to other reactions involving, e.g., atomic oxygen. Thus the impact of vibrationally excited OH on the ozone or Ox sink remains small. Among quiescent atmospheres under investigation, the largest while still small (less than 0.1% effect was found for the polar winter upper stratosphere and mesosphere. The contribution of the reaction of vibrationally excited OH with ozone to the OH sink is largest in the upper polar winter stratosphere (up to 4%, while its effect on the HO2 source is larger in the lower thermosphere (up to 1.5% for polar winter and 2.5% for midlatitude night conditions. For OH(v=0...9+O the effective rate coefficients are lower by up to 11% than those involving OH in its vibrational ground state. The effects on the odd oxygen sink are negative and can reach −3% (midlatitudinal nighttime lowermost thermosphere, i.e. neglecting vibrational excitation overestimates the odd

  15. Vibrationally elastic and inelastic scattering of electrons by hydrogen sulphide molecules

    International Nuclear Information System (INIS)

    Nishimura, Tamio; Itikawa, Yukikazu

    1996-01-01

    Vibrationally elastic and inelastic cross sections (differential and integral ones) are calculated for electron scattering from hydrogen sulphide (H 2 S) at the collision energies 3-30 eV. Vibrational excitation of all three fundamental modes is considered. The calculation is based on the rotationally sudden and a vibrationally close-coupling method using an ab initio electrostatic potential. The effects of electron exchange and target polarization are taken into account approximately. The resulting cross sections are compared with the experimental data available. The present differential cross sections (DCS) for the elastic scattering reproduce the experimental data well. For the inelastic scattering, the present DCS is too small at 3 eV, compared with the experimental data. This is probably due to a shape resonance, which the present calculation would not be sufficiently accurate to produce. In the higher energy region (i.e. above about 10 eV), the present vibrational cross section should be more reliable, but no experimental data are available so far. (Author)

  16. Multi-layer Lanczos iteration approach to calculations of vibrational energies and dipole transition intensities for polyatomic molecules

    International Nuclear Information System (INIS)

    Yu, Hua-Gen

    2015-01-01

    We report a rigorous full dimensional quantum dynamics algorithm, the multi-layer Lanczos method, for computing vibrational energies and dipole transition intensities of polyatomic molecules without any dynamics approximation. The multi-layer Lanczos method is developed by using a few advanced techniques including the guided spectral transform Lanczos method, multi-layer Lanczos iteration approach, recursive residue generation method, and dipole-wavefunction contraction. The quantum molecular Hamiltonian at the total angular momentum J = 0 is represented in a set of orthogonal polyspherical coordinates so that the large amplitude motions of vibrations are naturally described. In particular, the algorithm is general and problem-independent. An application is illustrated by calculating the infrared vibrational dipole transition spectrum of CH based on the ab initio T8 potential energy surface of Schwenke and Partridge and the low-order truncated ab initio dipole moment surfaces of Yurchenko and co-workers. A comparison with experiments is made. The algorithm is also applicable for Raman polarizability active spectra

  17. The Utilization of Low Frequency Raman Spectra of Gases for the Study of Molecules with Large Amplitude Vibration

    Institute of Scientific and Technical Information of China (English)

    James R. Durig; Sarah Xiao-hua Zhou; Joshua Klaassen; Arindam Ganguly

    2009-01-01

    The utilization of the Raman spectra of the low frequency bending mode for three quasi-linear molecules, disiloxane, (SiH3)2 O; methylisocyanate, CH3NCO; and dimethy lisocyanate, (CH3)2SiHNCO for observing the low frequency anharmonic bending vibration is demonstrated which is superior to the corresponding far infrared spectra. From the observed frequencies from the Raman spectra the potential function governing the heavy atom motion to linearity has been obtained from which the barrier has been determined. These experimental values are compared to the ab ini-tio predicted values. Also low frequency Raman spectra of the ring puckering vibration of chlorocy-clobutane, c-C4H7Cl, bromocyclobutane, c-C4H7Br, and aminocyclobutane, c-C4H7NH2, have been utilized to obtain the potential function governing the ring inversion for these molecules. The deter-mined barriers to planarity are compared to those obtained from MP2 (full) ab initio and density functional theory B3LYP calculations by utilizing a variety of basis sets. For all of these studies it is shown that the Raman spectra are superior to the infrared spectra for determining the frequencies of the excited state transitions.

  18. CN molecule vibrational spectra excitation in several LTE plasma sources conditions

    International Nuclear Information System (INIS)

    Iova, I.; Iova, Floriana; Ionita, I.; Bazavan, M.; Ilie, Gh.; Stanescu, G.

    2001-01-01

    Our interest in CN plasma study steams of the facilities to obtain the CN radicals in a free atmosphere electric discharge where the C of the coal electrodes can to combine in the enough high temperature plasma with the atmospheric nitrogen. Also of much interest is the very important phenomena in which the CN vibrational spectra can be implied and used as a diagnostic tool (plasma chemistry, astrophysics and so on). A peculiar importance presents the CN vibrational spectra in the transient plasmas. It is the reason why we have investigated here some internal processes of a continued and interrupted arc of various pulse lengths. To these purposes we present with enough accuracy the behaviour of the relative band head intensities of the sequences Δ v = +1 and Δ v = 0 belonging to the CN electronic transition (B 2 Σ - X 2 Σ), as a function of the pulse length (50 - 200 ms) as well as a function of the cathode to anode separation. These behaviours give us indications on the vibrational levels of the electronic state populations in several regions of the arc plasma as well on the efficiency of these levels excitation for several plasma pulse lengths. (authors)

  19. Water-mediated influence of a crowded environment on internal vibrations of a protein molecule.

    Science.gov (United States)

    Kuffel, Anna; Zielkiewicz, Jan

    2016-02-14

    The influence of crowding on the protein inner dynamics is examined by putting a single protein molecule close to one or two neighboring protein molecules. The presence of additional molecules influences the amplitudes of protein fluctuations. Also, a weak dynamical coupling of collective velocities of surface atoms of proteins separated by a layer of water is detected. The possible mechanisms of these phenomena are described. The cross-correlation function of the collective velocities of surface atoms of two proteins was decomposed into the Fourier series. The amplitude spectrum displays a peak at low frequencies. Also, the results of principal component analysis suggest that the close presence of an additional protein molecule influences the high-amplitude, low-frequency modes in the most prominent way. This part of the spectrum covers biologically important protein motions. The neighbor-induced changes in the inner dynamics of the protein may be connected with the changes in the velocity power spectrum of interfacial water. The additional protein molecule changes the properties of solvation water and in this way it can influence the dynamics of the second protein. It is suggested that this phenomenon may be described, at first approximation, by a damped oscillator driven by an external random force. This model was successfully applied to conformationally rigid Choristoneura fumiferana antifreeze protein molecules.

  20. Vibrational energy transfer in selectively excited diatomic molecules. [Relaxation rates, self-relaxation, upper limits

    Energy Technology Data Exchange (ETDEWEB)

    Dasch, C.J.

    1978-09-01

    Single rovibrational states of HCl(v=2), HBr(v=2), DCl(v=2), and CO(v=2) were excited with a pulsed optical parametric oscillator (OPO). Total vibrational relaxation rates near - resonance quenchers were measured at 295/sup 0/K using time resolved infrared fluorescence. These rates are attributed primarily to V - V energy transfer, and they generally conform to a simple energy gap law. A small deviation was found for the CO(v) + DCl(v') relaxation rates. Upper limits for the self relaxation by V - R,T of HCl(v=2) and HBr(v=2) and for the two quantum exchange between HCl and HBr were determined. The HF dimer was detected at 295/sup 0/K and 30 torr HF pressure with an optoacoustic spectrometer using the OPO. Pulsed and chopped, resonant and non-resonant spectrophones are analyzed in detail. From experiments and first order perturbation theory, these V - V exchange rates appear to behave as a first order perturbation in the vibrational coordinates. The rotational dynamics are known to be complicated however, and the coupled rotational - vibrational dynamics were investigated theoreticaly in infinite order by the Dillon and Stephenson and the first Magnus approximations. Large ..delta..J transitions appear to be important, but these calculations differ by orders of magnitude on specific rovibrational transition rates. Integration of the time dependent semiclassical equations by a modified Gordon method and a rotationally distorted wave approximation are discussed as methods which would treat the rotational motion more accurately. 225 references.

  1. The dance of molecules: new dynamical perspectives on highly excited molecular vibrations.

    Science.gov (United States)

    Kellman, Michael E; Tyng, Vivian

    2007-04-01

    At low energies, molecular vibrational motion is described by the normal modes model. This model breaks down at higher energy, with strong coupling between normal modes and onset of chaotic dynamics. New anharmonic modes are born in bifurcations, or branchings of the normal modes. Knowledge of these new modes is obtained through the window of frequency-domain spectroscopy, using techniques of nonlinear classical dynamics. It may soon be possible to "watch" molecular rearrangement reactions spectroscopically. Connections are being made with reaction rate theories, condensed phase systems, and motions of electrons in quantum dots.

  2. Matrix elements of vibration kinetic energy operator of tetrahedral molecules in non-orthogonal-dependent coordinates

    Science.gov (United States)

    Protasevich, Alexander E.; Nikitin, Andrei V.

    2018-01-01

    In this work, we propose an algorithm for calculating the matrix elements of the kinetic energy operator for tetrahedral molecules. This algorithm uses the dependent six-angle coordinates (6A) and takes into account the full symmetry of molecules. Unlike A.V. Nikitin, M. Rey, and Vl. G. Tyuterev who operate with the kinetic energy operator only in Radau orthogonal coordinates, we consider a general case. The matrix elements are shown to be a sum of products of one-dimensional integrals.

  3. Ion-molecule interactions of biological importance. A vibrational spectroscopic study of magnesium complexes with hydroxylated quinones; Interactions ions-molecules d'interet biologique. Etude par spectrometrie de vibrations de la complexation du magnesium avec des molecules quinoniques hydroxylees

    Energy Technology Data Exchange (ETDEWEB)

    Kirszenbaum, Marek

    1976-06-14

    Luteoskyrin and rugulosin are two naturally occurring yellow pigments with hydroxylated bis-anthraquinonic structures. They cause serious liver disorders in man due to the formation of complexes of the type pigment-Mg{sup 2+}-DNA. In order to elucidate the structure of these complexes we have studied the vibrational spectra of some model systems, namely 1-hydroxy- and 1,4-dihydroxyanthraquinone, their magnesium chelate complexes, and a series of simpler complexes as the acetylacetonates of some divalent metals. Complete vibrational assignment are proposed for anthraquinone-9,10, the two hydroxylated and deureroxylated derivatives and their magnesium complexes. The substitution of {sup 26}Mg in place of {sup 24}Mg in these complexes enabled us to assign the Mg-O vibrations; their number corresponds to a hexa-coordinated metal in the acetylacetonate case and to a tetra-coordinated structure in the anthraquinone-olates complexes. The position of the ν C=0 and ν C-0 vibrations bands in the complexes shows that the bonds in the chelated ring of Mg(1-O-AQ){sub 2} retains their single and double bond characteristic whereas in the CMg(1,4-O{sub 2},-AQ){sub n} a resonating structure appears in the ring. The study of the IR and R spectra of the complexes enabled a tetrahedral structure to be proposed for the oxygens around the magnesium. Finally it was noted that the Mg-O bonds possessed a high degree of covalent character. (author) [French] La luteoskyrine et la rugulosine, deux pigments jaunes de structure de bis-anthraquinones hydroxylees, provoquent des troubles hepatiques graves par la formation des complexes pigment-Mg{sup 2+}-ADN. Dans le but d'eclaircir la structure de ces complexes nous avons etudie, par spectrometrie de vibrations, les systemes-modeles suivants: la 1-hydroxy- et la 1,4-dihydroxyanthraquinones, leurs complexes magnesies et une serie des complexes plus simples, tels que les acetylacetonates. de metaux divalents. Nous avons propose une attribution

  4. Optimized geometry, vibration (IR and Raman spectra and nonlinear optical activity of p-nitroanilinium perchlorate molecule: A theoretical study

    Directory of Open Access Journals (Sweden)

    Tamer Ömer

    2016-03-01

    Full Text Available The molecular modeling of p-nitroanilinium perchlorate molecule was carried out by using B3LYP and HSEH1PBE levels of density functional theory (DFT. The IR and Raman spectra were simulated and the assignments of vibrational modes were performed on the basis of relative contribution of various internal co-ordinates. NBO analysis was performed to demonstrate charge transfer, conjugative interactions and the formation of intramolecular hydrogen bonding interactions within PNAPC. Obtained large dipole moment values showed that PNAPC is a highly polarizable complex, and the charge transfer occurs within PNAPC. Hydrogen bonding and charge transfer interactions were also displayed by small HOMO-LUMO gap and molecular electrostatic potential (MEP surface. The strong evidences that the material can be used as an efficient nonlinear optical (NLO material of PNAPC were demonstrated by considerable polarizability and hyperpolarizability values obtained at DFT levels.

  5. Vibrationally resolved photoionization of the 1σg and 1σu shells of N2 molecule

    International Nuclear Information System (INIS)

    Semenov, S K; Cherepkov, N A; Matsumoto, M; Fujiwara, K; Ueda, K; Kukk, E; Tahara, F; Sunami, T; Yoshida, H; Tanaka, T; Nakagawa, K; Kitajima, M; Tanaka, H; De Fanis, A

    2006-01-01

    Theoretical and experimental study of vibrationally resolved partial photoionization cross sections and angular asymmetry parameter β for the 1σ g and 1σ u shells of N 2 molecule in the region of the σ* shape resonance is reported. The measurements were made at the synchrotron radiation facility SPring-8 in Japan. The calculations in the random phase approximation have been performed using the relaxed core Hartree-Fock wavefunctions with the fractional charge of the ion core equal to 0.7. With its help, the role of interchannel coupling between the closely spaced 1σ g and 1σ u shells was studied. The experiment demonstrates the existence of a correlational maximum in the 1σ u shell photoionization cross section induced by the σ* shape resonance in the 1σ g shell. This maximum reveals itself even more clearly in the angular asymmetry parameter β for the v' = 0 and v' = 1 vibrational states of the ion. The calculation in the random phase approximation gives a consistent interpretation of the experimental data

  6. Analysis of functional organic molecules at noble metal surfaces by means of vibrational spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Leyssner, Felix

    2011-10-24

    The goal of this work is to optimize the efficiency of photoinduced molecular switching processes on surfaces via controlled variations of the adsorption and electronic properties of the switch. We investigated the influence of external stimuli, i.e. photons and thermal activation, on surface bound molecular switches undergoing trans/cis-isomerizations and ring-opening/closing-reactions, respectively. High resolution electron energy loss spectroscopy (HREELS) and sum-frequency generation (SFG) spectroscopy have been used as the main tools to investigate the adsorption behavior and the molecular switching properties. Two basic concepts of coupling the molecular switch to the surface have been studied: (i) physisorbed or weakly chemisorbed systems deposited on noble metal surfaces under UHV conditions and (ii) molecular switches bound covalently via anchor groups. In the HREELS study following concept (i), we investigated the adsorption geometry and isomerization behavior of various molecular switches on metal substrates which are able to undergo a photoinduced trans/cis-isomerization in solution. We investigated three isoelectronic molecules on Au where we systematically changed the photochemically active group from the diazo-group in an azobenzene-derivative (on Cu(111)) to the imine-group, and the vinylene-group, respectively. Finding the photoisomerization quenched for all systems we observed considerable differences in their thermal isomerization behavior. Comparable we find the photoinduced ring-opening/closing-reaction of spiropyran quenched on Au(111) but a thermally induced ring-opening reaction resulting in the open form being strongly stabilized by the metal. SFG spectroscopy is employed to investigate the reversible, photoinduced trans/cis-isomerization of an azobenzene-functionalized self-assembled monolayer (SAM) on gold using a tripodal linker system. In consequence of the decoupling provided by the tripodal linker, the switching behavior of the

  7. A variable-temperature scanning tunneling microscope capable of single-molecule vibrational spectroscopy

    International Nuclear Information System (INIS)

    Stipe, B.C.; Rezaei, M.A.; Ho, W.

    1999-01-01

    The design and performance of a variable-temperature scanning tunneling microscope (STM) is presented. The microscope operates from 8 to 350 K in ultrahigh vacuum. The thermally compensated STM is suspended by springs from the cold tip of a continuous flow cryostat and is completely surrounded by two radiation shields. The design allows for in situ dosing and irradiation of the sample as well as for the exchange of samples and STM tips. With the STM feedback loop off, the drift of the tip-sample spacing is approximately 0.001 Angstrom/min at 8 K. It is demonstrated that the STM is well-suited for the study of atomic-scale chemistry over a wide temperature range, for atomic-scale manipulation, and for single-molecule inelastic electron tunneling spectroscopy (IETS). copyright 1999 American Institute of Physics

  8. Resummation of divergent perturbation series: Application to the vibrational states of H{sub 2}CO molecule

    Energy Technology Data Exchange (ETDEWEB)

    Duchko, A. N. [National Research Tomsk Polytechnic University, Tomsk (Russian Federation); V.E. Zuev Institute of Atmospheric Optics, Tomsk (Russian Federation); Bykov, A. D., E-mail: adbykov@rambler.ru [V.E. Zuev Institute of Atmospheric Optics, Tomsk (Russian Federation)

    2015-10-21

    Large-order Rayleigh–Schrödinger perturbation theory (RSPT) is applied to the calculation of anharmonic vibrational energy levels of H{sub 2}CO molecule. We use the model of harmonic oscillators perturbed by anharmonic terms of potential energy. Since the perturbation series typically diverge due to strong couplings, we apply the algebraic approximation technique because of its effectiveness shown earlier by Goodson and Sergeev [J. Chem. Phys. 110, 8205 (1999); ibid. 124, 094111 (2006)] and in our previous articles [A. D. Bykov et al. Opt. Spectrosc. 114, 396 (2013); ibid. 116, 598 (2014)]. To facilitate the resummation of terms contributing to perturbed states, when resonance mixing between states is especially strong and perturbation series diverge very quick, we used repartition of the Hamiltonian by shifting the normal mode frequencies. Energy levels obtained by algebraic approximants were compared with the results of variational calculation. It was found that for low energy states (up to ∼5000 cm{sup −1}), algebraic approximants gave accurate values of energy levels, which were in excellent agreement with the variational method. For highly excited states, strong and multiple resonances complicate series resummation, but a suitable change of normal mode frequencies allows one to reduce the resonance mixing and to get accurate energy levels. The theoretical background of the problem of RSPT series divergence is discussed along with its numerical analysis. For these purposes, the vibrational energy is considered as a function of a complex perturbation parameter. Layout and classification of its singularities allow us to model the asymptotic behavior of the perturbation series and prove the robustness of the algorithm.

  9. Optical transition probabilities in electron-vibration-rotation spectra of diatomic molecules

    International Nuclear Information System (INIS)

    Kuznetsova, L.A.; Kuz'menko, N.E.; Kuzyakov, Yu.Ya.; Plastinin, Yu.A.

    1974-01-01

    The present review systematizes the data on the absolute probabilities of electron transitions in diatomic molecules, which have been published since the beginning of 1961 and up to the end of 1973, and those on the relative transition probabilities, which have been published since the beginning of 1966 till the end of 1973. The review discussed the theoretical relationships underlying the experimental techniques of determining the absolute transition probabilities. Modifications of the techniques under discussion are not specially examined; the details of interest can be found, however, in the references cited. The factual material-, such as the values of the absolute probabilities of electron transitions, the dependences of the electron transition moments on the internuclear distance and the values of the Franck-Condon factors,- is presented in tables 1, 2 and 4, respectively, embracing all the relevant works known to the present authors. Along with a complete systematization of the transition probability data, the authors have attempted a critical analysis of the available data in order to select the most reliable results. The recommended values of the squared matrix elements of the electron transition dipole moments are given in table 3. The last chaper of the work compares the results of calculations of the Franck-Condon factors obtained with the different milecular potentials [ru

  10. Numerical-analytic implementation of the higher-order canonical Van Vleck perturbation theory for the interpretation of medium-sized molecule vibrational spectra.

    Science.gov (United States)

    Krasnoshchekov, Sergey V; Isayeva, Elena V; Stepanov, Nikolay F

    2012-04-12

    Anharmonic vibrational states of semirigid polyatomic molecules are often studied using the second-order vibrational perturbation theory (VPT2). For efficient higher-order analysis, an approach based on the canonical Van Vleck perturbation theory (CVPT), the Watson Hamiltonian and operators of creation and annihilation of vibrational quanta is employed. This method allows analysis of the convergence of perturbation theory and solves a number of theoretical problems of VPT2, e.g., yields anharmonic constants y(ijk), z(ijkl), and allows the reliable evaluation of vibrational IR and Raman anharmonic intensities in the presence of resonances. Darling-Dennison and higher-order resonance coupling coefficients can be reliably evaluated as well. The method is illustrated on classic molecules: water and formaldehyde. A number of theoretical conclusions results, including the necessity of using sextic force field in the fourth order (CVPT4) and the nearly vanishing CVPT4 contributions for bending and wagging modes. The coefficients of perturbative Dunham-type Hamiltonians in high-orders of CVPT are found to conform to the rules of equality at different orders as earlier proven analytically for diatomic molecules. The method can serve as a good substitution of the more traditional VPT2.

  11. Some new four-parameter potentials and their use in the study of vibrational thermodynamical quantities of diatomic molecules

    International Nuclear Information System (INIS)

    Sarvpreet Kaur; Mahajan, C.G.

    1999-01-01

    Three four-parameter potentials, U I , U II and U III have been proposed and their accuracy has been demonstrated by finding the mean square deviation from the true RKR potential curve for 15 electronic states of 12 diatomic molecules. Their percentage average mean square deviations from RKR curve have been found to be 1.45, 1.86 and 2.89 respectively. These compare favourably with the value 2.67 for the recently suggested four-parameter potential of Wei Hua which itself yields better results than the commonly employed three-parameter potentials. The superiority of the new potentials (especially of U I and U II ) has been further established by using these potentials to calculate the molecular constants α e and ω e χ e , following Dunham's method. The corresponding percentage average mean deviations for α e turn out to be 3.75, 5.13 and 15.43 and for ω e χ e 8.73, 17.23 and 27.49, respectively, against the respective values of 7.97 and 18.88 with Wei Hua's four-parameter potential. Also included are the values of dissociation energy determined with these potentials and these too corroborate the better performance of U I and U II . The relative worth of various potential functions has been further tested by carrying out numerical study of vibrational partition function (evaluated by sum over states method), entropy and thermal capacity for the ground state of 7 molecules and comparing these with the corresponding findings based on the RKR data. (author)

  12. Emission spectra of the species ablated from a solid target submerged in liquid: vibrational temperature of C2 molecules in water-confined geometry

    International Nuclear Information System (INIS)

    Sakka, Tetsuo; Saito, Kotaro; Ogata, Yukio H.

    2002-01-01

    Emission spectra of C 2 molecules produced at the water-graphite interface by pulsed laser irradiation were obtained at various delay times from the irradiation. Vibrational temperature was determined by the Boltzmann plot based on the vibrational bands in Δν=-1 branch of the Swan system. The results show that it was ca. 5000 K and did not change significantly with the delay time. With increasing the delay time up to ca. 500 ns the signal from the Swan band disappeared before the decrease of the vibrational temperature. The results were explained by the formation of a gas cavity and its collapse at several hundreds of nanoseconds from the laser pulse

  13. Nodeless vibrational amplitudes and quantum nonadiabatic dynamics in the nested funnel for a pseudo Jahn-Teller molecule or homodimer

    Science.gov (United States)

    Peters, William K.; Tiwari, Vivek; Jonas, David M.

    2017-11-01

    The nonadiabatic states and dynamics are investigated for a linear vibronic coupling Hamiltonian with a static electronic splitting and weak off-diagonal Jahn-Teller coupling through a single vibration with a vibrational-electronic resonance. With a transformation of the electronic basis, this Hamiltonian is also applicable to the anti-correlated vibration in a symmetric homodimer with marginally strong constant off-diagonal coupling, where the non-adiabatic states and dynamics model electronic excitation energy transfer or self-exchange electron transfer. For parameters modeling a free-base naphthalocyanine, the nonadiabatic couplings are deeply quantum mechanical and depend on wavepacket width; scalar couplings are as important as the derivative couplings that are usually interpreted to depend on vibrational velocity in semiclassical curve crossing or surface hopping theories. A colored visualization scheme that fully characterizes the non-adiabatic states using the exact factorization is developed. The nonadiabatic states in this nested funnel have nodeless vibrational factors with strongly avoided zeroes in their vibrational probability densities. Vibronic dynamics are visualized through the vibrational coordinate dependent density of the time-dependent dipole moment in free induction decay. Vibrational motion is amplified by the nonadiabatic couplings, with asymmetric and anisotropic motions that depend upon the excitation polarization in the molecular frame and can be reversed by a change in polarization. This generates a vibrational quantum beat anisotropy in excess of 2/5. The amplitude of vibrational motion can be larger than that on the uncoupled potentials, and the electronic population transfer is maximized within one vibrational period. Most of these dynamics are missed by the adiabatic approximation, and some electronic and vibrational motions are completely suppressed by the Condon approximation of a coordinate-independent transition dipole between

  14. Vibrational and cascade dissociation of H{sub 2}{sup +} ions by collision with gas molecules; Dissociation vibrationnelle et dissociation en cascade d'ions H{sub 2}{sup +} par collisions avec les molecules d'un gaz

    Energy Technology Data Exchange (ETDEWEB)

    Verveer, P [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1966-07-01

    Protons produced by collisional dissociation of H{sub 2}{sup +} ions have an energy spectrum with a narrow central peak. For a part the protons in this peak are produced by vibrational dissociation and for another part by a cascade of two collisions. For H{sub 2}{sup +} ions of 50 to 150 keV the cross section for vibrational dissociation is about 4.1 10{sup -19} cm{sup 2}/molecule in hydrogen and 1.1 10{sup -18} cm{sup 2}/molecule in argon. (author) [French] Les protons resultant de la dissociation par collisions d'ions H{sub 2}{sup +} dans un gaz ont un spectre d'energie qui presente un pic central tres etroit. Les protons dans ce pic proviennent, pour une part de la dissociation vibrationnelle et pour l'autre part d'une suite de deux collisions. Dans le domaine d'energie des ions H{sub 2}{sup +} de 50 a 150 keV la section efficace de dissociation vibrationnel vaut 4.1 10{sup -19} cm{sup 2}/molecule pour l'hydrogene et 1,1 10{sup -18} cm{sup 2}/molecule pour l'argon.

  15. Symbolic derivation of high-order Rayleigh-Schroedinger perturbation energies using computer algebra: Application to vibrational-rotational analysis of diatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Herbert, John M. [Kansas State Univ., Manhattan, KS (United States). Dept. of Chemistry

    1997-01-01

    Rayleigh-Schroedinger perturbation theory is an effective and popular tool for describing low-lying vibrational and rotational states of molecules. This method, in conjunction with ab initio techniques for computation of electronic potential energy surfaces, can be used to calculate first-principles molecular vibrational-rotational energies to successive orders of approximation. Because of mathematical complexities, however, such perturbation calculations are rarely extended beyond the second order of approximation, although recent work by Herbert has provided a formula for the nth-order energy correction. This report extends that work and furnishes the remaining theoretical details (including a general formula for the Rayleigh-Schroedinger expansion coefficients) necessary for calculation of energy corrections to arbitrary order. The commercial computer algebra software Mathematica is employed to perform the prohibitively tedious symbolic manipulations necessary for derivation of generalized energy formulae in terms of universal constants, molecular constants, and quantum numbers. As a pedagogical example, a Hamiltonian operator tailored specifically to diatomic molecules is derived, and the perturbation formulae obtained from this Hamiltonian are evaluated for a number of such molecules. This work provides a foundation for future analyses of polyatomic molecules, since it demonstrates that arbitrary-order perturbation theory can successfully be applied with the aid of commercially available computer algebra software.

  16. Torsion-inversion tunneling patterns in the CH-stretch vibrationally excited states of the G12 family of molecules including methylamine.

    Science.gov (United States)

    Dawadi, Mahesh B; Bhatta, Ram S; Perry, David S

    2013-12-19

    Two torsion-inversion tunneling models (models I and II) are reported for the CH-stretch vibrationally excited states in the G12 family of molecules. The torsion and inversion tunneling parameters, h(2v) and h(3v), respectively, are combined with low-order coupling terms involving the CH-stretch vibrations. Model I is a group theoretical treatment starting from the symmetric rotor methyl CH-stretch vibrations; model II is an internal coordinate model including the local-local CH-stretch coupling. Each model yields predicted torsion-inversion tunneling patterns of the four symmetry species, A, B, E1, and E2, in the CH-stretch excited states. Although the predicted tunneling patterns for the symmetric CH-stretch excited state are the same as for the ground state, inverted tunneling patterns are predicted for the asymmetric CH-stretches. The qualitative tunneling patterns predicted are independent of the model type and of the particular coupling terms considered. In model I, the magnitudes of the tunneling splittings in the two asymmetric CH-stretch excited states are equal to half of that in the ground state, but in model II, they differ when the tunneling rate is fast. The model predictions are compared across the series of molecules methanol, methylamine, 2-methylmalonaldehyde, and 5-methyltropolone and to the available experimental data.

  17. Rate coefficients for dissociative attachment and resonant electron-impact dissociation involving vibrationally excited O{sub 2} molecules

    Energy Technology Data Exchange (ETDEWEB)

    Laporta, V. [Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari, Italy and Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom); Celiberto, R. [Dipartimento di Ingegneria Civile, Ambientale, del Territorio, Edile e di Chimica, Politecnico di Bari, Italy and Istituto di Metodologie Inorganiche e dei Plasmi, CNR, Bari (Italy); Tennyson, J. [Department of Physics and Astronomy, University College London, London WC1E 6BT (United Kingdom)

    2014-12-09

    Rate coefficients for dissociative electron attachment and electron-impact dissociation processes, involving vibrationally excited molecular oxygen, are presented. Analytical fits of the calculated numerical data, useful in the applications, are also provided.

  18. Spectroscopic diagnostics of the vibrational population in the ground state of H2 and D2 molecules

    International Nuclear Information System (INIS)

    Fantz, U.; Heger, B.

    1998-01-01

    A diagnostic method has been evaluated for measuring the relative vibrational ground-state population of molecular hydrogen and deuterium. It is based on the analysis of the diagonal Fulcher bands · 3 Π u →a 3 Σ g + ) and the Franck-Condon principle of excitation. The validity of the underlying assumptions was verified by experiments in microwave discharges and the method is recommended for application in divertor plasmas in controlled fusion experiments. By attributing a vibrational temperature T vib to the ground-state electronic level (X 1 Σ g + ) and assuming population via the Franck-Condon principle, the upper Fulcher state vibrational distribution can be derived theoretically with T vib as parameter. Comparison with experimentally derived upper-state population gives the corresponding T vib of the ground state. The Franck-Condon factors for the · 3 Π 1 Σ g + and · 3 Π u →a 3 Σ g + transitions have been calculated for both hydrogen and deuterium from molecular constants using the FCFRKR code. The method has been applied to low pressure H 2 /He and D 2 /He microwave plasmas, showing good agreement of experimentally and theoretically derived upper Fulcher state vibrational distributions. The vibrational temperatures range from 3200 K to 6800 K for H 2 and 2600 K to 4000 K for D 2 · depending on molecular density, pressure and electron temperature, but indicating nearly the same vibrational population for H 2 and D 2 for comparable plasma conditions. (author)

  19. Theoretical study on the molecular structure and vibrational properties, NBO and HOMO-LUMO analysis of the POX3 (X = F, Cl, Br, I) series of molecules

    Science.gov (United States)

    Galván, Jorge E.; Gil, Diego M.; Lanús, Hernán E.; Altabef, Aida Ben

    2015-02-01

    The fourth member of the series of compounds of the type POX3 with X = I was synthesized and characterized by infrared spectroscopy. The geometrical parameters and vibrational properties of POX3 (X = F, Cl, Br, I) molecules were investigated theoretically by means DFT and ab initio methods. Available geometrical and vibrational data were used together with theoretical calculations in order to obtain a set of scaled force constants. The observed trends in geometrical parameters are analyzed and compared with those obtained in a previous work for the VOX3 (X = F, Cl, Br, I) series of compounds. NBO analysis was performed in order to know the hyper-conjugative interactions that favor one structure over another. The molecular properties such as ionization potential, electron affinity, electronegativity, chemical potential, chemical hardness, softness and global electrophilicity index have been deduced from HOMO-LUMO analysis.

  20. Energía financiera

    OpenAIRE

    Altuve G., José G.

    2016-01-01

    La energía financiera surge como consecuencia de la unión de los conceptos energía y financiera. La primera, como la acción a seguir en un momento del tiempo, y la segunda vinculada al manejo de variables tales como: Estructura financiera y su costo de capital y, las decisiones de inversión consideradas bajo riesgo. Si se armonizan estos dos aspectos estamos en presencia de la fusión de la energía y la administración financiera en dos de sus variables más importantes. Financial power arise...

  1. Theoretical investigation of molecular structure and vibrational spectra of 4,5-bis-(2-isopropyl-5- methylphenoxy) phthalonitrile molecule

    International Nuclear Information System (INIS)

    Avci, D.

    2005-01-01

    The molecular geometry and vibrational frequencies of 4,5-bis-(2-isopropyl-5- methylphenoxy) phthalonitrile in the ground state have been calculated using the Hartree- Fock (HF) and density functional method (B3LYP) with 6-31G(d) basis set. The optimized geometric bond lengths and bond angles obtained by using HF and DFT (B3LYP) show the best agreement with the experimental data. Comparison of the observed fundamental vibrational frequencies of 4,5-bis-(2-isopropyl-5-methylphenoxy) phthalonitrile with calculated results by density functional B3LYP and Hartree-Fock methods indicate that B3LYP is superior to the scaled Hartree-Fock approach for molecular vibrational problems

  2. Ground state hydrogen conformations and vibrational analysis of 1,2-dihdroxyanthraquinone (alizarin) molecule by AB initio Hartree-Fock and density functional theory calculations

    International Nuclear Information System (INIS)

    Delta, E.; Ucun, F.; Saglam, A.

    2010-01-01

    The ground state hydrogen conformations of 1,2-dihydroxyanthraquinone (alizarin) molecule have been investigated using ab initio Hartree-Fock (HF) and density functional theory (B3LYP) methods with 6-31G(d,p) basis set. The calculations indicate that the compound in the ground state exist with the doubly bonded O atom linked intra molecularly by the two hydrogen bonds. The vibrational analyses of the ground state conformation of the compound were also made and its optimized geometry parameters were given.

  3. Nanomechanical microcantilever operated in vibration modes with use of RNA aptamer as receptor molecules for label-free detection of HCV helicase.

    Science.gov (United States)

    Hwang, Kyo Seon; Lee, Sang-Myung; Eom, Kilho; Lee, Jeong Hoon; Lee, Yoon-Sik; Park, Jung Ho; Yoon, Dae Sung; Kim, Tae Song

    2007-11-30

    We report the nanomechanical microcantilevers operated in vibration modes (oscillation) with use of RNA aptamers as receptor molecules for label-free detection of hepatitis C virus (HCV) helicase. The nanomechanical detection principle is that the ligand-receptor binding on the microcantilever surface induces the dynamic response change of microcantilevers. We implemented the label-free detection of HCV helicase in the low concentration as much as 100 pg/ml from measuring the dynamic response change of microcantilevers. Moreover, from the recent studies showing that the ligand-receptor binding generates the surface stress on the microcantilever, we estimate the surface stress, on the oscillating microcantilevers, induced by ligand-receptor binding, i.e. binding between HCV helicase and RNA aptamer. In this article, it is suggested that the oscillating microcantilevers with use of RNA aptamers as receptor molecules may enable one to implement the sensitive label-free detection of very small amount of small-scale proteins.

  4. Stretching dependence of the vibration modes of a single-molecule Pt-H-2-Pt bridge

    DEFF Research Database (Denmark)

    Djukic, D.; Thygesen, Kristian Sommer; Untiedt, C.

    2005-01-01

    isotope substitution is obtained. The stretching dependence for each of the modes allows uniquely classifying them as longitudinal or transversal modes. The interpretation of the experiment in terms of a Pt-H-2-Pt bridge is verified by density-functional theory calculations for the stability, vibrational...

  5. Highly vibrationally excited O2 molecules in low-pressure inductively-coupled plasmas detected by high sensitivity ultra-broad-band optical absorption spectroscopy

    Science.gov (United States)

    Foucher, Mickaël; Marinov, Daniil; Carbone, Emile; Chabert, Pascal; Booth, Jean-Paul

    2015-08-01

    Inductively-coupled plasmas in pure O2 (at pressures of 5-80 mTorr and radiofrequency power up to 500 W) were studied by optical absorption spectroscopy over the spectral range 200-450 nm, showing the presence of highly vibrationally excited O2 molecules (up to vʺ = 18) by Schumann-Runge band absorption. Analysis of the relative band intensities indicates a vibrational temperature up to 10,000 K, but these hot molecules only represent a fraction of the total O2 density. By analysing the (11-0) band at higher spectral resolution the O2 rotational temperature was also determined, and was found to increase with both pressure and power, reaching 900 K at 80 mTorr 500 W. These measurements were achieved using a new high-sensitivity ultra-broad-band absorption spectroscopy setup, based on a laser-plasma light source, achromatic optics and an aberration-corrected spectrograph. This setup allows the measurement of weak broadband absorbances due to a baseline variability lower than 2   ×   10-5 across a spectral range of 250 nm.

  6. A Computer Assisted Procedure of Assignments of Vibration-Rotation Bands of Asymmetric and Symmetric Top Molecules

    Czech Academy of Sciences Publication Activity Database

    Urban, Štěpán; Behrend, J.; Pracna, Petr

    2004-01-01

    Roč. 690, - (2004), s. 105-114 ISSN 0022-2860 R&D Projects: GA MŠk ME 445; GA ČR GA203/01/1274 Institutional research plan: CEZ:AV0Z4040901 Keywords : assigments of vibration-rotation spectra * combination differences * Loomis-Wood algorithm Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.200, year: 2004

  7. An improved model of radiative transfer for the NLTE problem in the NIR bands of CO2 and CO molecules in the daytime atmosphere of Mars. 2. Population of vibrational states

    Science.gov (United States)

    Ogibalov, V. P.; Shved, G. M.

    2017-09-01

    The near-infrared (NIR) emission of the Martian atmosphere in the CO2 bands at 4.3, 2.7, 2.0, 1.6, 1.4, 1.3, 1.2, and 1.05 µm and in the CO bands at 4.7, 2.3, 1.6, and 1.2 µm is mainly generated under nonlocal thermodynamic equilibrium (NLTE) conditions for vibrational states, the transitions from which form the specified bands. The paper presents the results of simulations of the population of these states under NLTE for daytime conditions. In the cold high-latitude troposphere, the NLTE takes place much lower than in the troposphere under typical temperature conditions. If the NIR-radiation reflection from the surface is ignored, the population of high vibrational states substantially decreases, at least, in some layer of the lower atmosphere. However, inelastic collisions of CO2 and CO molecules with O atoms produce no considerable influence on the values of populations. The population of vibrational states, the transitions from which form NIR bands, is also almost insensitive to possible large values of the quenching-in-collision rate constants of vibrational states higher than CO2(0001). However, very large errors in the estimates of the population of vibrational states of the CO2 molecule (rather than the CO molecule!) can be caused by the uncertainty in the values of the rate constant of exchange between CO2 molecules by the energy quantum of the asymmetric stretching vibrational mode. For this intermolecular exchange, we recommend a possible way to restrict the vibrational excitation degree of the molecule that is a collision partner and to maintain simultaneously a sufficiently high accuracy in the population estimate.

  8. Selective excitation of a vibrational level within the electronic ground state of a polyatomic molecule with ultra short pulses

    CSIR Research Space (South Africa)

    De Clercq, L

    2010-09-01

    Full Text Available al lbl d i I e I e dt ω ωρ ρ ρ − = − = −∑h (1) where, , .a b a bω ω ω= − , (2) ρab gives the elements of the density matrix, ωa the frequencies... of the individual vibrational levels, and Iab the matrix elements of the interaction Hamiltonian [2] which include the detailed time dependence of the shaped femtosecond pulse. 2. Simulation results A transform limited 150 femtosecond laser pulse with a...

  9. Application of R-matrix theory to resonant reactive electron-molecule scattering: Vibrational excitation and dissociative attachment of N2 and F2

    International Nuclear Information System (INIS)

    Wong, C.F.; Light, J.C.

    1984-01-01

    Based on the R-matrix approach of Schneider et al. [J. Phys. B 12, L 365 (1979)] to reactive electron-molecule scattering, a new propagative R-matrix method (PRMM) is presented which is more appropriate for polyatomic systems. The new method should be useful in other calculations where complicated integrals need to be propagated. We also introduce an effective R-matrix model (ERMM) in which the usual resonance parameters (potential and width) can be used as input in model R-matrix calculations. The PRMM and ERMM have been applied to the electron-N 2 system and the electron-F 2 system. The results agree very well with previous calculations for both vibrationally inelastic scattering and dissociative attachment when identical potentials and parameters are used

  10. Dynamics of liquids, molecules, and proteins measured with ultrafast 2D IR vibrational echo chemical exchange spectroscopy.

    Science.gov (United States)

    Fayer, M D

    2009-01-01

    A wide variety of molecular systems undergo fast structural changes under thermal equilibrium conditions. Such transformations are involved in a vast array of chemical problems. Experimentally measuring equilibrium dynamics is a challenging problem that is at the forefront of chemical research. This review describes ultrafast 2D IR vibrational echo chemical exchange experiments and applies them to several types of molecular systems. The formation and dissociation of organic solute-solvent complexes are directly observed. The dissociation times of 13 complexes, ranging from 4 ps to 140 ps, are shown to obey a relationship that depends on the complex's formation enthalpy. The rate of rotational gauche-trans isomerization around a carbon-carbon single bond is determined for a substituted ethane at room temperature in a low viscosity solvent. The results are used to obtain an approximate isomerization rate for ethane. Finally, the time dependence of a well-defined single structural transformation of a protein is measured.

  11. Vibrational dynamics of adsorbed molecules under conditions of photodesorption: Pump-probe SFG spectra of CO/Pt(111)

    Science.gov (United States)

    Fournier, Frédéric; Zheng, Wanquan; Carrez, Serge; Dubost, Henri; Bourguignon, Bernard

    2004-09-01

    Interaction of CO adsorbed on Pt(111) with electrons and phonons is studied experimentally by means of a pump-probe experiment where CO is probed by IR+visible sum frequency generation under a pump laser intensity that allows photodesorption. Vibrational spectra of CO internal stretch are obtained as a function of pump-probe delay. A two-temperature and anharmonic coupling model is used to extract from the spectra the real time variations of CO peak frequency and dephasing time. The main conclusions are the following: (i) The CO stretch is perturbed by two low-frequency modes, assigned to frustrated rotation and frustrated translation. (ii) The frustrated rotation is directly coupled to electrons photoexcited in Pt(111) by the pump laser. (iii) There is no evidence of Pt-CO stretch excitation in the spectra. The implications for the photodesorption dynamics are discussed.

  12. General principles of vibrational spectroscopies

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.

    2000-01-01

    Atoms in molecules and solids do not remain in fixed relative positions, but vibrate about some mean position. This vibrational motion is quantized and at room temperature, most of the molecules in a given sample are in their lowest vibrational state. Absorption of electromagnetic radiation with

  13. Study on excitation of vibrational levels of osmium tetroxide molecule by the continuous CO2 laser radiation

    International Nuclear Information System (INIS)

    Kompanets, O.N.; Letokhov, V.S.; Minogin, V.G.

    1975-01-01

    The mechanism of nonlinear infrared absorption in OsO 4 has been studied using a single-frequence continuous-wave CO 2 laser (10.6 μ). Measured are relationships between the OsO 4 absorption coefficient and the laser radiation intensity, the week beam transmission through a cell filled with OsO 4 and the frequency of the intensity modulation of the strong beam which saturates the absorption. It is indicated that the thermal mechanism prevails in OsO 4 bleaching under pressure (>=) 1mm Hg. A strong infrared fluorescence observed and studied at 5.3 and 10.6 μ in the molecular OsO 4 in the field of the high-power CO 2 laser has supplied another proof of the conclusion. The thermal diffusion rate and the coefficient of thermal conductivity for OsO 4 vapours have been determined. It has been revealed that the hot bands represent a significant part in thermal mechanism of the laser radiation absorption by the molecule

  14. Heterogeneous Dynamics of Coupled Vibrations

    NARCIS (Netherlands)

    Cringus, Dan; Jansen, Thomas I. C.; Pshenichnikov, Maxim S.; Schoenlein, RW; Corkum, P; DeSilvestri, S; Nelson, KA; Riedle, E

    2009-01-01

    Frequency-dependent dynamics of coupled stretch vibrations of a water molecule are revealed by 2D IR correlation spectroscopy. These are caused by non-Gaussian fluctuations of the environment around the individual OH stretch vibrations.

  15. A harmonic approximation of intramolecular vibrations in a mixed quantum-classical methodology: Linear absorbance of a dissolved Pheophorbid-a molecule as an example

    International Nuclear Information System (INIS)

    Megow, Joerg; Kulesza, Alexander; Qu Zhengwang; Ronneberg, Thomas; Bonacic-Koutecky, Vlasta; May, Volkhard

    2010-01-01

    Graphical abstract: Structure of a single Pheo (green: C-atoms, blue: N-atoms, red; O-atoms, light grey: H-atoms). - Abstract: Linear absorption spectra of a single Pheophorbid-a molecule (Pheo) dissolved in ethanol are calculated in a mixed quantum-classical approach. In this computational scheme the absorbance is mainly determined by the time-dependent fluctuations of the energy gap between the Pheo ground and excited electronic state. The actual magnitude of the energy gap is caused by the electrostatic solvent solute coupling as well as by contributions due to intra Pheo vibrations. For the latter a new approach is proposed which is based on precalculated potential energy surfaces (PES) described in a harmonic approximation. To get the respective nuclear equilibrium configurations and Hessian matrices of the two involved electronic states we carried out the necessary electronic structure calculations in a DFT-framework. Since the Pheo changes its spatial orientation in the course of a MD run, the nuclear equilibrium configurations change their spatial position, too. Introducing a particular averaging procedure, these configurations are determined from the actual MD trajectories. The usability of the approach is underlined by a perfect reproduction of experimental data. This also demonstrates that our proposed method is suitable for the description of more complex systems in future investigations.

  16. A Combined Probe-Molecule, Mössbauer, Nuclear Resonance Vibrational Spectroscopy, and Density Functional Theory Approach for Evaluation of Potential Iron Active Sites in an Oxygen Reduction Reaction Catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Kneebone, Jared L. [Univ. of Rochester, Rochester, NY (United States); Daifuku, Stephanie L. [Univ. of Rochester, Rochester, NY (United States); Kehl, Jeffrey A. [Univ. of Rochester, Rochester, NY (United States); Wu, Gang [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chung, Hoon T. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hu, Michael Y. [Argonne National Lab. (ANL), Argonne, IL (United States); Alp, E. Ercan [Argonne National Lab. (ANL), Argonne, IL (United States); More, Karren L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zelenay, Piotr [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Holby, Edward F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Neidig, Michael L. [Univ. of Rochester, Rochester, NY (United States)

    2017-07-06

    While non-precious metal M-N-C (M = Fe or Co) catalysts have been developed that are effective for the oxygen reduction reaction in polymer electrolyte fuel cells, no consensus has yet been reached regarding the nature of the M sites in these heterogeneous catalysts that are responsible for reaction with dioxygen (O2). While multiple studies have developed correlations between Fe distributions in as-prepared catalysts and ORR activity, the direct identification of sites reactive towards O2 or O2-analog molecules remains a significant challenge. In the present study, we demonstrate a new approach to identifying and characterizing potential Fe active sites in complex ORR catalysts that combines an effective probe molecule (NO(g)) Mössbauer spectroscopy and nuclear resonance vibrational spectroscopy (NRVS) with density functional theory (DFT) calculations. Mössbauer spectroscopic studies demonstrate that NO(g) treatment of electrochemically reduced PANI-57Fe-C leads to selective reaction with only a sub-set of the Fe species present. Nuclear resonance vibrational spectroscopic studies identified new Fe-ligand vibrations associated with the site reactive towards NO(g). DFT calculations of vibrational properties of a small selection of previously proposed active site structures suggest that graphene zig-zag edge hosted Fe-N structures may be responsible for the observed vibrational behavior with NO(g) probe molecules. Moreover, such sites are likely also reactive to O2, possibly serving as the ORR active sites in the synthesized materials.

  17. Bandshapes in vibrational spectroscopy

    International Nuclear Information System (INIS)

    Dijkman, F.G.

    1978-01-01

    A detailed account is given of the development of modern bandshape theories since 1965. An investigation into the relative contributions of statistical irreversible relaxation processes is described, for a series of molecules in which gradually the length of one molecular axis is increased. An investigation into the theoretical and experimental investigation of the broadening brought about by the effect of fluctuating intermolecular potentials on the vibrational frequency is also described. The effect of an intermolecular perturbative potential on anharmonic and Morse oscillators is discussed and the results are presented of a computation on the broadening of the vibrational band of some diatomic molecules in a rigid lattice type solvent. The broadening of the OH-stretching vibration in a number of aliphatic alcohols, the vibrational bandshapes of the acetylenic C-H stretching vibration and of the symmetric methyl stretching vibration are investigated. (Auth./ C.F.)

  18. Energizing porters by proton-motive force.

    Science.gov (United States)

    Nelson, N

    1994-11-01

    It is generally accepted that the chemistry of water was the most crucial determinant in shaping life on earth. Among the more important chemical features of water is its dissociation into protons and hydroxyl ions. The presence of relatively high proton concentrations in the ambient solution resulted in the evolution of proton pumps during the dawn of life on earth. These proton pumps maintained neutral pH inside the cells and generated electrochemical gradients of protons (proton-motive force) across their membranes. The existence of proton-motive force enabled the evolution of porters driven by it that are most probably among the more primitive porters in the world. The directionality of the substrate transport by the porters could be to both sides of the membranes because they can serve as proton symporters or antiporters. One of the most important subjects of this meeting is the mechanism by which proton-motive and other ion-motive forces drive the transport processes through porters. Is there a common mechanism of action for all proton-driven porters? Is there some common partial reaction by which we can identify the way that porters are energized by proton-motive force? Is there a common coupling between proton movement and uptake or secretion of certain molecules? Even a partial answer to one of these questions would advance our knowledge... or confusion. As my mentor Efraim Racker used to say: 'If you are not totally confused you do not understand the issue'.

  19. The Dynamics of Large-Amplitude Motion in Energized Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Perry, David S. [Univ. of Akron, OH (United States). Dept. of Chemistry

    2016-05-27

    Chemical reactions involve large-amplitude nuclear motion along the reaction coordinate that serves to distinguish reactants from products. Some reactions, such as roaming reactions and reactions proceeding through a loose transition state, involve more than one large-amplitude degree of freedom. Because of the limitation of exact quantum nuclear dynamics to small systems, one must, in general, define the active degrees of freedom and separate them in some way from the other degrees of freedom. In this project, we use large-amplitude motion in bound model systems to investigate the coupling of large-amplitude degrees of freedom to other nuclear degrees of freedom. This approach allows us to use the precision and power of high-resolution molecular spectroscopy to probe the specific coupling mechanisms involved, and to apply the associated theoretical tools. In addition to slit-jet spectra at the University of Akron, the current project period has involved collaboration with Michel Herman and Nathalie Vaeck of the Université Libre de Bruxelles, and with Brant Billinghurst at the Canadian Light Source (CLS).

  20. Assessing energy efficiency of electric car bottom furnaces intended for thermal energization of minerals

    Science.gov (United States)

    Nizhegorodov, A. I.

    2017-01-01

    The paper deals with a new concept of electric furnaces for roasting and thermal energization of vermiculite and other minerals with vibrational transportation of a single-layer mass under constant thermal field. The paper presents performance calculation and comparative assessment of energy data for furnaces of different modifications: flame and electric furnaces with three units, furnaces with six units and ones with series-parallel connection of units, and furnaces of new concept.

  1. Energía mareomotriz: potencial energético y medio ambiente

    Directory of Open Access Journals (Sweden)

    Julián Rodrigo Quintero González

    2015-07-01

    Full Text Available La energía mareomotriz ha tenido un gran desarrollo en relación a su potencial energético y el estudio de sus impactos ambientales. Este trabajo presenta una perspectiva acerca de estos dos aspectos que han sido ampliamente evaluados en diferentes países. Se concluye que el potencial energético de la energía mareomotriz es significativo, en relación con las capacidades instaladas de las plantas de energía actualmente en operación, con el incremento de la producción energética anual y con el número de nuevos proyectos en el marco global. Se indica también que existen impactos ambientales moderados con su implementación.

  2. Theory of sum-frequency generation spectroscopy of adsorbed molecules using the density matrix method-broadband vibrational sum-frequency generation and applications

    International Nuclear Information System (INIS)

    Bonn, M; Ueba, H; Wolf, M

    2005-01-01

    A generalized theory of frequency- and time-resolved vibrational sum-frequency generation (SFG) spectroscopy of adsorbates at surfaces is presented using the density matrix formalism. Our theoretical treatment is specifically aimed at addressing issues that accompany the relatively novel SFG approach using broadband infrared pulses. The ultrashort duration of these pulses makes them ideally suited for time-resolved investigations, for which we present a complete theoretical treatment. A second key characteristic of these pulses is their large bandwidth and high intensity, which allow for highly non-linear effects, including vibrational ladder climbing of surface vibrations. We derive general expressions relating the density matrix to SFG spectra, and apply these expressions to specific experimental results by solving the coupled optical Bloch equations of the density matrix elements. Thus, we can theoretically reproduce recent experimentally demonstrated hot band SFG spectra using femtosecond broadband infrared excitation of carbon monoxide (CO) on a Ru(001) surface

  3. A multi-reference singles and doubles configuration interaction determination in the dissociation energy and vibrational levels of the BeF molecules in the X2Σ + state

    International Nuclear Information System (INIS)

    Machado, F.B.C.; Ornellas, F.R.

    1988-10-01

    An accurate potential energy curve for the BeF molecule in the X 2 Σ + state is calculated within the MRSDCI approach. Vibrational level spacings and the dissociation energy are reported. Agreement with the available experimental spacings is 15 cm -1 on the average. The theoretically computed D o , 5.92 eV, favors the experimental value of 5.85 eV over the higher value of 6.26 eV. Arguments are also presented that show why the value obtained by the Birge-Sponer linear extrapolation is accidentally a good one. (author) [pt

  4. Energized Oxygen : Speiser Current Sheet Bifurcation

    Science.gov (United States)

    George, D. E.; Jahn, J. M.

    2017-12-01

    A single population of energized Oxygen (O+) is shown to produce a cross-tail bifurcated current sheet in 2.5D PIC simulations of the magnetotail without the influence of magnetic reconnection. Treatment of oxygen in simulations of space plasmas, specifically a magnetotail current sheet, has been limited to thermal energies despite observations of and mechanisms which explain energized ions. We performed simulations of a homogeneous oxygen background, that has been energized in a physically appropriate manner, to study the behavior of current sheets and magnetic reconnection, specifically their bifurcation. This work uses a 2.5D explicit Particle-In-a-Cell (PIC) code to investigate the dynamics of energized heavy ions as they stream Dawn-to-Dusk in the magnetotail current sheet. We present a simulation study dealing with the response of a current sheet system to energized oxygen ions. We establish a, well known and studied, 2-species GEM Challenge Harris current sheet as a starting point. This system is known to eventually evolve and produce magnetic reconnection upon thinning of the current sheet. We added a uniform distribution of thermal O+ to the background. This 3-species system is also known to eventually evolve and produce magnetic reconnection. We add one additional variable to the system by providing an initial duskward velocity to energize the O+. We also traced individual particle motion within the PIC simulation. Three main results are shown. First, energized dawn- dusk streaming ions are clearly seen to exhibit sustained Speiser motion. Second, a single population of heavy ions clearly produces a stable bifurcated current sheet. Third, magnetic reconnection is not required to produce the bifurcated current sheet. Finally a bifurcated current sheet is compatible with the Harris current sheet model. This work is the first step in a series of investigations aimed at studying the effects of energized heavy ions on magnetic reconnection. This work differs

  5. 2008 Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Philip J. Reid

    2009-09-21

    The conference focuses on using vibrational spectroscopy to probe structure and dynamics of molecules in gases, liquids, and interfaces. The goal is to bring together a collection of researchers who share common interests and who will gain from discussing work at the forefront of several connected areas. The intent is to emphasize the insights and understanding that studies of vibrations provide about a variety of systems.

  6. Coherent vibrational dynamics

    CERN Document Server

    Lanzani, Guglielmo; De Silvestri, Sandro

    2007-01-01

    Vibrational spectroscopy is a powerful investigation tool for a wide class of materials covering diverse areas in physics, chemistry and biology. The continuous development in the laser field regarding ultrashort pulse generation has led to the possibility of producing light pulses that can follow vibrational motion coupled to the electronic transitions in molecules and solids in real time. Aimed at researchers and graduate students using vibrational spectroscopy, this book provides both introductory chapters as well as more advanced contents reporting on recent progress. It also provides a good starting point for scientists seeking a sound introduction to ultrafast optics and spectroscopic techniques.

  7. Cosecha de energía

    OpenAIRE

    García Ojero, Jesús

    2016-01-01

    En este trabajo se analizarán los distintos métodos conocidos de extraer energía de fuentes tanto naturales como las producidas por el ser humano, entre las que se pueden distinguir las vibraciones mecánicas, gradientes de temperatura o las ondas electromagnéticas emitidas por aparatos electrónicos. Primero realizaremos una revisión bibliográfica de distintos métodos de obtención de energía a partir de vibraciones mecánicas, utilizando materiales piezoeléctricos y actuadores electromagnéticos...

  8. Role conflict: cause of burnout or energizer?

    Science.gov (United States)

    Jones, M L

    1993-03-01

    A year-long study of public child welfare administrators examined the effects of role conflict on their attitudes and performance. Popular belief and some of the literature have suggested that burnout is inevitable for those confronted with role conflict. Other literature has proposed that it may instead be energizing to individuals and lead to greater personal and organizational effectiveness. This qualitative study found that individuals in the study had developed specific, effective skills for responding to role conflict. Although there was a public presentation of self that indicated they were under stress and in "impossible" situations, there was in fact an energizing effect resulting from the ongoing challenge of dealing with conflict.

  9. Final Technical Report, reEnergize Program

    Energy Technology Data Exchange (ETDEWEB)

    Wamstad-Evans, Kristi [City of Omaha; Williams, Eric [City of Omaha; Kubicek, Jason [City of Omaha

    2013-12-27

    The reEnergize Program helped to build a market for residential and commercial energy evaluations and upgrades. The program provided incentives to encourage participants to save energy, save money, and make their homes and businesses more safe, healthy, and comfortable. As part of the Better Buildings Neighborhood Program (BBNP), the successful investment of this $10 million grant toward market development was the first grant funding collaboration between the cities of Omaha and Lincoln. Through more than three years of work, thousands of participants, contractors, and community members worked together to make the reEnergize Program a demonstration of how to “Build Energy Smart Communities.”

  10. Simple systematization of vibrational excitation cross-section calculations for resonant electron-molecule scattering in the boomerang and impulse models.

    Science.gov (United States)

    Sarma, Manabendra; Adhikari, S; Mishra, Manoj K

    2007-01-28

    Vibrational excitation (nu(f), where psi(nu(i))(R,t) approximately =e(-iH(A(2))-(R)t/h phi(nu(i))(R) with time evolution under the influence of the resonance anionic Hamiltonian H(A(2) (-))(A(2) (-)=N(2)(-)/H(2) (-)) implemented using Lanczos and fast Fourier transforms. The target (A(2)) vibrational eigenfunctions phi(nu(i))(R) and phi(nu(f))(R) are calculated using Fourier grid Hamiltonian method applied to potential energy (PE) curves of the neutral target. Application of this simple systematization to calculate vibrational structure in e-N(2) and e-H(2) scattering cross-sections provides mechanistic insights into features underlying presence/absence of structure in e-N(2) and e-H(2) scattering cross-sections. The results obtained with approximate PE curves are in reasonable agreement with experimental/calculated cross-section profiles, and cross correlation functions provide a simple demarcation between the boomerang and impulse models.

  11. Vibrational, structural and electronic properties investigation by DFT calculations and molecular docking studies with DNA topoisomerase II of strychnobrasiline type alkaloids: A theoretical approach for potentially bioactive molecules

    Science.gov (United States)

    Costa, Renyer A.; Oliveira, Kelson M. T.; Costa, Emmanoel Vilaça; Pinheiro, Maria L. B.

    2017-10-01

    A combined experimental and theoretical DFT study of the structural, vibrational and electronic properties of strychnobrasiline and 12-hydroxy-10,11-dimethoxystrychnobrasiline is presented using the Becke three-parameter Lee-Yang-Parr function (B3LYP) and 6-311G(2d,p) basis set. The theoretical geometry optimization data were compared with the X-ray data for a similar structure in the associated literature, showing close values. The calculated HOMO-LUMO gap values showed that the presence of substituents in the benzene ring influences the quantum properties which are directly related to the reactive properties. Theoretical UV spectra agreed well with the measured experimental data, with bands assigned. In addition, Natural Bond Orbitals (NBOs), Mapped molecular electrostatic potential surface (MEPS) and NLO calculations were also performed at the same theory level. The theoretical vibrational analysis revealed several characteristic vibrations that may be used as a diagnostic tool for other strychnobrasiline type alkaloids, simplifying their identification and structural characterization. Molecular docking calculations with DNA Topoisomerase II-DNA complex showed binding free energies values of -8.0 and -9.5 kcal/mol for strychnobrasiline and 12-hydroxy-10,11-dimethoxystrychnobrasiline respectively, while for amsacrine, used for the treatment of leukemia, the binding free energy ΔG presented a value of -10.0 kcal/mol, suggesting that strychnobrasiline derivative alkaloids might exhibit an antineoplastic activity.

  12. Pathways for Energization of Ca in Mercury's Exosphere

    Science.gov (United States)

    Killen, Rosemary M.

    2015-01-01

    We investigate the possible pathways to produce the extreme energy observed in the calcium exosphere of Mercury. Any mechanism must explain the facts that Ca in Mercury's exosphere is extremely hot, that it is seen almost exclusively on the dawnside of the planet, and that its content varies seasonally, not sporadically. Simple diatomic molecules or their clusters are considered, focusing on calcium oxides while acknowledging that Ca sulfides may also be the precursor molecules. We first discuss impact vaporization to justify the assumption that CaO and Ca-oxide clusters are expected from impacts on Mercury. Then we discuss processes by which the atomic Ca is energized to a 70,000 K gas. The processes considered are (1) electron-impact dissociation of CaO molecules, (2) spontaneous dissociation of Ca-bearing molecules following impact vaporization, (3) shock-induced dissociative ionization, (4) photodissociation and (5) sputtering. We conclude that electron-impact dissociation cannot produce the required abundance of Ca, and sputtering cannot reproduce the observed spatial and temporal variation that is measured. Spontaneous dissociation is unlikely to result in the high energy that is seen. Of the two remaining processes, shock induced dissociative ionization produces the required energy and comes close to producing the required abundance, but rates are highly dependent on the incoming velocity distribution of the impactors. Photodissociation probably can produce the required abundance of Ca, but simulations show that photodissociation cannot reproduce the observed spatial distribution.

  13. Molecular vibrations the theory of infrared and Raman vibrational spectra

    CERN Document Server

    Wilson, E Bright; Cross, Paul C

    1980-01-01

    Pedagogical classic and essential reference focuses on mathematics of detailed vibrational analyses of polyatomic molecules, advancing from application of wave mechanics to potential functions and methods of solving secular determinant.

  14. Herbal Energizers: Speed By Any Other Name.

    Science.gov (United States)

    Jenkins, Andrew P.

    This guide focuses on over-the-counter (OTC) stimulants sold to high school aged athletes and dieters as "herbal energizers," food supplements, and fatigue reducers. While advertising often makes them appear healthful and harmless, all of these stimulants belong in the class "sympathomimetic amines," so called because they…

  15. Temas de Física para Ingeniería: Trabajo y energía

    OpenAIRE

    Beléndez, Augusto; Pastor Antón, Carlos; Bernabeu, Guillermo

    1988-01-01

    Apuntes de Mecánica: "Trabajo y energía". Trabajo y potencia. Energía cinética, teorema de la energía cinética. Fuerzas conservativas, energía potencial. Energía potencial gravitatoria. Principio de conservación de la energía mecánica. Choques.

  16. Discrete Visible Luminescence of Helium Atoms and Molecules Desorbing from Helium Clusters: The Role of Electronic, Vibrational, and Rotational Energy Transfer

    International Nuclear Information System (INIS)

    von Haeften, K.; von Pietrowski, R.; Moeller, T.; Joppien, M.; Moussavizadeh, L.; de Castro, A.R.

    1997-01-01

    Discrete visible and near-infrared luminescence of a beam of photoexcited helium clusters is reported. The emission lines are attributed to free helium atoms and molecules desorbing from clusters in electronically excited states. Depending on the excitation energy, various atomic and molecular singlet and triplet states are involved in the relaxation process. With increasing cluster size the intensity of molecular transitions becomes dominant. The temperature of ejected molecules could be estimated to T vib ∼2500 K and T rot ∼450 K and is much higher than that of the cluster itself. copyright 1997 The American Physical Society

  17. Vibrational excitation from heterogeneous catalysis

    International Nuclear Information System (INIS)

    Purvis, G.D. III; Redmon, M.J.; Woken, G. Jr.

    1979-01-01

    Classical trajectories have been used by numerous researchers to investigate the dynamics of exothermic chemical reactions (atom + diatom) with a view toward understanding what leads to vibrational excitation of the product molecule. Unlike these studies, the case where the reaction is catalyzed by a solid surface is considered. The trajectory studies indicate that there should be conditions under which considerable vibrational energy appears in the product molecules without being lost to the solid during the course of the reaction. 2 figures, 3 tables

  18. Vibrational Spectral Studies of Gemfibrozil

    Science.gov (United States)

    Benitta, T. Asenath; Balendiran, G. K.; James, C.

    2008-11-01

    The Fourier Transform Raman and infrared spectra of the crystallized drug molecule 5-(2,5-Dimethylphenoxy)-2,2-dimethylpentanoic acid (Gemfibrozil) have been recorded and analyzed. Quantum chemical computational methods have been employed using Gaussian 03 software package based on Hartree Fock method for theoretically modeling the grown molecule. The optimized geometry and vibrational frequencies have been predicted. Observed vibrational modes have been assigned with the aid of normal coordinate analysis.

  19. Formation of H- ions via vibrational excited molecules produced from recombinative wall desorption of H atoms in a low-pressure H/sub 2/ positive column

    NARCIS (Netherlands)

    Amorim, J.; Loureiro, J.; Schram, D.C.

    2001-01-01

    Recombinative wall desorption of hydrogen atoms in a low-pressure hydrogen positive column leading to formation of H/sub 2/ (X/sup 1/ Sigma /sub g//sup +/, v) molecules in optimum levels for H/sup -/ production by dissociative attachment is investigated. We employed a kinetic model that solves the

  20. Vibrational Spectroscopy and Astrobiology

    Science.gov (United States)

    Chaban, Galina M.; Kwak, D. (Technical Monitor)

    2001-01-01

    Role of vibrational spectroscopy in solving problems related to astrobiology will be discussed. Vibrational (infrared) spectroscopy is a very sensitive tool for identifying molecules. Theoretical approach used in this work is based on direct computation of anharmonic vibrational frequencies and intensities from electronic structure codes. One of the applications of this computational technique is possible identification of biological building blocks (amino acids, small peptides, DNA bases) in the interstellar medium (ISM). Identifying small biological molecules in the ISM is very important from the point of view of origin of life. Hybrid (quantum mechanics/molecular mechanics) theoretical techniques will be discussed that may allow to obtain accurate vibrational spectra of biomolecular building blocks and to create a database of spectroscopic signatures that can assist observations of these molecules in space. Another application of the direct computational spectroscopy technique is to help to design and analyze experimental observations of ice surfaces of one of the Jupiter's moons, Europa, that possibly contains hydrated salts. The presence of hydrated salts on the surface can be an indication of a subsurface ocean and the possible existence of life forms inhabiting such an ocean.

  1. Vibration mixer

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, S.A.; Chernov, V.S.; Denisenko, V.V.; Gorodnyanskiy, I.F.; Prokopov, L.I.; Tikhonov, Yu.P.

    1983-01-01

    The vibration mixer is proposed which contains a housing, vibration drive with rod installed in the upper part of the mixing mechanism made in the form of a hollow shaft with blades. In order to improve intensity of mixing and dispersion of the mud, the shaft with the blades is arranged on the rod of the vibrator and is equipped with a cam coupling whose drive disc is attached to the vibration rod. The rod is made helical, while the drive disc of the cam coupling is attached to the helical surface of the rod. In addition, the vibration mixer is equipped with perforated discs installed on the ends of the rods.

  2. 29 CFR 1926.957 - Construction in energized substations.

    Science.gov (United States)

    2010-07-01

    ... Distribution § 1926.957 Construction in energized substations. (a) Work near energized equipment facilities. (1... lines. When it is necessary to deenergize equipment or lines for protection of employees, the... large electrical equipment, transformers, or breakers. (f) Storage. The storage requirements of § 1926...

  3. Dynamics of Activated Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Mullin, Amy S. [Univ. of Maryland, College Park, MD (United States)

    2016-11-16

    Experimental studies have been performed to investigate the collisional energy transfer processes of gas-phase molecules that contain large amounts of internal energy. Such molecules are prototypes for molecules under high temperature conditions relevant in combustion and information about their energy transfer mechanisms is needed for a detailed understanding and modeling of the chemistry. We use high resolution transient IR absorption spectroscopy to measure the full, nascent product distributions for collisions of small bath molecules that relax highly vibrationally excited pyrazine molecules with E=38000 cm-1 of vibrational energy. To perform these studies, we developed new instrumentation based on modern IR light sources to expand our experimental capabilities to investigate new molecules as collision partners. This final report describes our research in four areas: the characterization of a new transient absorption spectrometer and the results of state-resolved collision studies of pyrazine(E) with HCl, methane and ammonia. Through this research we have gained fundamental new insights into the microscopic details of relatively large complex molecules at high energy as they undergo quenching collisions and redistribute their energy.

  4. PREFACE: Vibrations at surfaces Vibrations at surfaces

    Science.gov (United States)

    Rahman, Talat S.

    2011-12-01

    This special issue is dedicated to the phenomenon of vibrations at surfaces—a topic that was indispensible a couple of decades ago, since it was one of the few phenomena capable of revealing the nature of binding at solid surfaces. For clean surfaces, the frequencies of modes with characteristic displacement patterns revealed how surface geometry, as well as the nature of binding between atoms in the surface layers, could be different from that in the bulk solid. Dispersion of the surface phonons provided further measures of interatomic interactions. For chemisorbed molecules on surfaces, frequencies and dispersion of the vibrational modes were also critical for determining adsorption sites. In other words, vibrations at surfaces served as a reliable means of extracting information about surface structure, chemisorption and overlayer formation. Experimental techniques, such as electron energy loss spectroscopy and helium-atom-surface scattering, coupled with infra-red spectroscopy, were continually refined and their resolutions enhanced to capture subtleties in the dynamics of atoms and molecules at surfaces. Theoretical methods, whether based on empirical and semi-empirical interatomic potential or on ab initio electronic structure calculations, helped decipher experimental observations and provide deeper insights into the nature of the bond between atoms and molecules in regions of reduced symmetry, as encountered on solid surfaces. Vibrations at surfaces were thus an integral part of the set of phenomena that characterized surface science. Dedicated workshops and conferences were held to explore the variety of interesting and puzzling features revealed in experimental and theoretical investigations of surface vibrational modes and their dispersion. One such conference, Vibrations at Surfaces, first organized by Harald Ibach in Juelich in 1980, continues to this day. The 13th International Conference on Vibrations at Surfaces was held at the University of

  5. Ship Vibrations

    DEFF Research Database (Denmark)

    Sørensen, Herman

    1997-01-01

    Methods for calculating natural frequencies for ship hulls and for plates and panels.Evaluation of the risk for inconvenient vibrations on board......Methods for calculating natural frequencies for ship hulls and for plates and panels.Evaluation of the risk for inconvenient vibrations on board...

  6. Isotope separation process by transfer of vibrational energy

    International Nuclear Information System (INIS)

    Angelie, C.; Cauchetier, M.; Paris, J.

    1983-01-01

    This process consists in exciting A molecules by absorption of a pulsed light beam, then in exciting until their dissociation X molecules, present in several isotopic forms, by a vibrational transfer between the A molecules and the X molecules, the A molecules having a dissociation energy greater than that of the X molecules, the duration and energy of the light pulses being such that the absorption time by the A molecules is less than the excitation time of the X molecules and the temperature conditions such that the thermal width of the vibration rays is at the most near the isotopic difference between the resonance rays of the two isotopic varieties [fr

  7. Dipole Correlation of the Electronic Structures of theConformations of Water Molecule Evolving Through theNormal Modes of Vibrations Between Angular (C2v to Linear(D∝h Shapes

    Directory of Open Access Journals (Sweden)

    Arindam Chakraborty

    2006-03-01

    Full Text Available In order to settle the issue of equivalence or non-equivalence of the two lone pairsof electrons on oxygen atom in water molecule, a quantum chemical study of the dipolecorrelation of the electronic structure of the molecule as a function of conformationsgenerated following the normal modes of vibrations between the two extremeconformations, C2v (∠HOH at 90o and D∝h (∠HOH at 180o, including the equilibrium one,has been performed. The study invokes quantum mechanical partitioning of moleculardipoles into bond moment and lone pair moment and localization of delocalized canonicalmolecular orbitals, CMO’s into localized molecular orbitals, LMO’s. An earlier suggestion,on the basis of photoelectron spectroscopy, that one lone pair is in p-type and the other is ins-type orbital of O atom of water molecule at its equilibrium shape, and also the qualitative“Squirrel Ears” structure are brought under serious scrutiny. A large number ofconformations are generated and the charge density matrix, dipole moment of eachconformation is computed in terms of the generated canonical molecular orbitals, CMO’sand then Sinanoğlu’s localization method is invoked to localize the CMO’s of eachconformation and the quantum mechanical hybridizations of all the bonds and lone pairs onO center are evaluated in terms of the localized molecular orbitals. Computed datademonstrate that the electronic structures i.e. two bond pairs and two lone pairs and itshybridization status of all conformations of water molecule are straightforward in terms ofthe LMO’s. It is further revealed that the pattern of orbital hybridization changescontinuously as a function of evolution of molecular shape. The close analysis of thegenerated LMO’s reveals that one lone pair is accommodated in a pure p orbital and anotherlone pair is in a hybrid

  8. La pobreza energética y sus implicaciones

    OpenAIRE

    Mikel González-Eguino

    2014-01-01

    32 p. El sector energético se enfrenta en las próximas décadas a tres grandes transformaciones relacionadas con el cambio climático, la seguridad de suministro y la pobreza energética. Las dos primeras han sido analizadas ampliamente. Sin embargo, la pobreza energética ha pasado más desapercibida a pesar de tener una gran influencia en la vida de millones de personas, especialmente en los países más pobres. Actualmente, 1.300 millones de personas (el 20% de la población mundial) no tienen ...

  9. Dissimilar Dynamics of Coupled Water Vibrations

    NARCIS (Netherlands)

    Jansen, Thomas L. C.; Cringus, Dan; Pshenichnikov, Maxim S.

    2009-01-01

    Dissimilar dynamics of coupled stretch vibrations of a water molecule are revealed by two-dimensional, IR correlation spectroscopy. These are caused by essentially non-Gaussian fluctuations of the electric field exerted by the environment on the individual OH stretch vibrations. Non-Gaussian

  10. Urban vibrations

    DEFF Research Database (Denmark)

    Morrison, Ann; Knudsen, L.; Andersen, Hans Jørgen

    2012-01-01

    In   this   paper   we   describe   a   field   study   conducted   with   a   wearable   vibration   belt   where   we   test   to   determine   the   vibration   intensity   sensitivity   ranges   on   a   large   diverse   group   of   participants   with   evenly   distributed  ages  and...

  11. Energía minihidráulica : una alternativa energética para electrificación rural

    OpenAIRE

    Agudelo Flórez, Sergio Cipriano; Chamorro Rendón, Luis Javier

    2002-01-01

    Entre las actividades del Grupo de Energía Alternativa (GEA) de la Facultad de Ingeniería de la Universidad de Antioquia, se pretende el desarrollo de prototipos que aprovechen las fuentes no convencionales para la producción de energía eléctrica y así satisfacer las necesidades insatisfechas de las viviendas rurales aisladas de la red energética nacional. En la región del Oriente antioqueño, se encontró un formidable recurso hidráulico de grandes ríos, quebradas y fuentes de agua cercanas a ...

  12. Radiation signatures from a locally energized flaring loop

    International Nuclear Information System (INIS)

    Emslie, A.G.; Vlahos, L.; and Institute for Plasma Research, Stanford University)

    1980-01-01

    We calculate the radiation signatures from a locally energized solar flare loop, at a variety of wavelengths. Our calculations depend strongly on the physical properties of the energy release mechanism which we qualitatively discuss

  13. Som Energia: sostenibilitat energètica i cooperativisme

    OpenAIRE

    Duran i Grant, Alexandre; Huijink, Gijsbert; Roselló, Marc

    2013-01-01

    La cooperativa Som Energia és una organització innovadora en el sector energètic a casa nostra. Proposa una forma de fer diferent de la de les empreses tradicionals del sector: ven energia renovable certificada, no té ànim de lucre i busca el bé comú. La proposta treballa per la sostenibilitat energètica.

  14. Energizing Subject Guide Service with Web 2.0

    Directory of Open Access Journals (Sweden)

    Sheau-Hwang Chang

    2014-06-01

    Full Text Available This article will use LibGuides as an example to illustrate how a Web 2.0 platform can energize the subject guide service and give librarians an edge in expanding their roles. Topics to be discussed will include a brief introduction to LibGuides and its capabilities to energize subject guide creation, how it has been used by academic libraries, how it is used in Maxwell Library in expanding librarian's role, and finally its implications on librarianship.

  15. Combined optimization model for sustainable energization strategy

    Science.gov (United States)

    Abtew, Mohammed Seid

    Access to energy is a foundation to establish a positive impact on multiple aspects of human development. Both developed and developing countries have a common concern of achieving a sustainable energy supply to fuel economic growth and improve the quality of life with minimal environmental impacts. The Least Developing Countries (LDCs), however, have different economic, social, and energy systems. Prevalence of power outage, lack of access to electricity, structural dissimilarity between rural and urban regions, and traditional fuel dominance for cooking and the resultant health and environmental hazards are some of the distinguishing characteristics of these nations. Most energy planning models have been designed for developed countries' socio-economic demographics and have missed the opportunity to address special features of the poor countries. An improved mixed-integer programming energy-source optimization model is developed to address limitations associated with using current energy optimization models for LDCs, tackle development of the sustainable energization strategies, and ensure diversification and risk management provisions in the selected energy mix. The Model predicted a shift from traditional fuels reliant and weather vulnerable energy source mix to a least cost and reliable modern clean energy sources portfolio, a climb on the energy ladder, and scored multifaceted economic, social, and environmental benefits. At the same time, it represented a transition strategy that evolves to increasingly cleaner energy technologies with growth as opposed to an expensive solution that leapfrogs immediately to the cleanest possible, overreaching technologies.

  16. Energizing Local Values For Tourism Services Improvement

    Directory of Open Access Journals (Sweden)

    Budi Purnomo

    2012-06-01

    Full Text Available People in most cultures would probably agree that politeness is needed during their interaction. However there may be differing opinions as to when they should be polite. In tourism industry, tourism service providers’ act as hosts and tourists act as guests. Typically hosts will try to act politely and use appropriate politeness norms when serving guests to ensure their satisfaction. The research findings show that the tourism service providers in Central Java use various unggah-ungguh ‘politeness norms’ when serving English speaking tourists and Indonesian speaking tourists. Besides that, there are some violations made by the tourism service providers in using unggah-ungguh ‘politeness norms’. The research findings also show that there are similar and different perspectives on unggah-ungguh ‘politeness norms’ between English speaking tourists with Western culture backgrounds and Indonesian speaking tourists with Indonesian culture backgrounds towards the politeness norms used by the tourism service providers in Central Java. The findings imply the needs of energizing unggah-ungguh ‘politeness norms’ which is discovered from well known noble Javanese values used by the tourism service providers for tourism service improvement.

  17. Electron-excited molecule interactions

    International Nuclear Information System (INIS)

    Christophorou, L.G.; Tennessee Univ., Knoxville, TN

    1991-01-01

    In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

  18. Vibrations and reorientations of H2O molecules in [Sr(H2O)6]Cl2 studied by Raman light scattering, incoherent inelastic neutron scattering and proton magnetic resonance.

    Science.gov (United States)

    Hetmańczyk, Joanna; Hetmańczyk, Lukasz; Migdał-Mikuli, Anna; Mikuli, Edward; Florek-Wojciechowska, Małgorzata; Harańczyk, Hubert

    2014-04-24

    Vibrational-reorientational dynamics of H2O ligands in the high- and low-temperature phases of [Sr(H2O)6]Cl2 was investigated by Raman Spectroscopy (RS), proton magnetic resonance ((1)H NMR), quasielastic and inelastic incoherent Neutron Scattering (QENS and IINS) methods. Neutron powder diffraction (NPD) measurements, performed simultaneously with QENS, did not indicated a change of the crystal structure at the phase transition (detected earlier by differential scanning calorimetry (DSC) at TC(h)=252.9 K (on heating) and at TC(c)=226.5K (on cooling)). Temperature dependence of the full-width at half-maximum (FWHM) of νs(OH) band at ca. 3248 cm(-1) in the RS spectra indicated small discontinuity in the vicinity of phase transition temperature, what suggests that the observed phase transition may be associated with a change of the H2O reorientational dynamics. However, an activation energy value (Ea) for the reorientational motions of H2O ligands in both phases is nearly the same and equals to ca. 8 kJ mol(-1). The QENS peaks, registered for low temperature phase do not show any broadening. However, in the high temperature phase a small QENS broadening is clearly visible, what implies that the reorientational dynamics of H2O ligands undergoes a change at the phase transition. (1)H NMR line is a superposition of two powder Pake doublets, differentiated by a dipolar broadening, suggesting that there are two types of the water molecules in the crystal lattice of [Sr(H2O)6]Cl2 which are structurally not equivalent average distances between the interacting protons are: 1.39 and 1.18 Å. However, their reorientational dynamics is very similar (τc=3.3⋅10(-10) s). Activation energies for the reorientational motion of these both kinds of H2O ligands have nearly the same values in an experimental error limit: and equal to ca. 40 kJ mole(-1). The phase transition is not seen in the (1)H NMR spectra temperature dependencies. Infrared (IR), Raman (RS) and inelastic

  19. City of Phoenix - Energize Phoenix Program

    Energy Technology Data Exchange (ETDEWEB)

    Laloudakis, Dimitrios J.

    2014-09-29

    Energize Phoenix (EPHX) was designed as an ambitious, large-scale, three-year pilot program to provide energy efficiency upgrades in buildings, along Phoenix’s new Light Rail Corridor – part of a federal effort to reduce energy consumption and stimulate job growth, while simultaneously reducing the country’s carbon footprint and promoting a shift towards a green economy. The program was created through a 2010 competitive grant awarded to the City of Phoenix who managed the program in partnership with Arizona State University (ASU), the state’s largest university, and Arizona Public Service (APS), the state’s largest electricity provider. The U.S. Department of Energy (DOE) Better Buildings Neighborhood Program (BBNP) and the American Recovery and Reinvestment Act (ARRA) of 2009 provided $25M in funding for the EPHX program. The Light Rail Corridor runs through the heart of downtown Phoenix, making most high-rise and smaller commercial buildings eligible to participate in the EPHX program, along with a diverse mix of single and multi-family residential buildings. To ensure maximum impact and deeper market penetration, Energize Phoenix was subdivided into three unique parts: i. commercial rebate program, ii. commercial financing program, and iii. residential program Each component was managed by the City of Phoenix in partnership with APS. Phoenix was fortunate to partner with APS, which already operated robust commercial and residential rebate programs within its service territory. Phoenix tapped into the existing utility contractor network, provided specific training to over 100 contracting firms, and leveraged the APS rebate program structure (energy efficiency funding) to launch the EPHX commercial and residential rebate programs. The commercial finance program was coordinated and managed through a contract with National Bank of Arizona, NBAZ, which also provided project capital leveraging EPHX finance funds. Working in unison, approved contractors

  20. Kinematic anharmonicity of internal rotation of molecules

    International Nuclear Information System (INIS)

    Bataev, V.A.; Pupyshev, V.I.; Godunov, I.A.

    2017-01-01

    The methods of analysis the strongly coupled vibrations are proposed for a number of molecules of aromatic and heterocyclic carbonyl (and some others) compounds. The qualitative principles are formulated for molecular systems with a significant kinematic anharmonicity.

  1. Lattice Vibrations in Chlorobenzenes:

    DEFF Research Database (Denmark)

    Reynolds, P. A.; Kjems, Jørgen; White, J. W.

    1974-01-01

    Lattice vibrational dispersion curves for the ``intermolecular'' modes in the triclinic, one molecule per unit cell β phase of p‐C6D4Cl2 and p‐C6H4Cl2 have been obtained by inelastic neutron scattering. The deuterated sample was investigated at 295 and at 90°K and a linear extrapolation to 0°K...... was applied in order to correct for anharmonic effects. Calculations based on the atom‐atom model for van der Waals' interaction and on general potential parameters for the aromatic compounds agree reasonably well with the experimental observations. There is no substantial improvement in fit obtained either...

  2. Experimental decoherence in molecule interferometry

    International Nuclear Information System (INIS)

    Hackermueller, L.; Hornberger, K.; Stibor, A.; Zeilinger, A.; Arndt, M.; Kiesewetter, G.

    2005-01-01

    Full text: We present three mechanisms of decoherence that occur quite naturally in matter wave interferometer with large molecules. One way molecules can lose coherence is through collision with background gas particles. We observe a loss of contrast with increasing background pressure for various types of gases. We can understand this phenomenon quantitatively with a new model for collisional decoherence which corrects older models by a factor of 2 π;. The second experiment studies the thermal emission of photons related to the high internal energy of the interfering molecules. When sufficiently many or sufficiently short photons are emitted inside the interferometer, the fringe contrast is lost. We can continuously vary the temperature of the molecules and compare the loss of contrast with a model based on decoherence theory. Again we find good quantitative agreement. A third mechanism that influences our interference pattern is dephasing due to vibrations of the interference gratings. By adding additional vibrations we study this effect in more detail. (author)

  3. Low pressure tritiation of molecules

    International Nuclear Information System (INIS)

    Moran, T.F.; Powers, J.C.; Lively, M.O.

    1980-01-01

    A method is described of tritiating sensitive biological molecules by depositing molecules of the substance to be tritiated on a supporting substrate in an evacuated vacuum chamber near, but not in the path of, an electron beam which traverses the chamber, admitting tritium gas into the chamber, and subjecting the tritium to the electron beam. Vibrationally excited tritium gas species are generated which collide and react with the substance thus incorporating tritium atoms into the substance. (U.K.)

  4. Vibrating minds

    CERN Multimedia

    2009-01-01

    Ed Witten is one of the leading scientists in the field of string theory, the theory that describes elementary particles as vibrating strings. This week he leaves CERN after having spent a few months here on sabbatical. His wish is that the LHC will unveil supersymmetry.

  5. Vibrational spectroscopy

    Science.gov (United States)

    Umesh P. Agarwal; Rajai Atalla

    2010-01-01

    Vibrational spectroscopy is an important tool in modern chemistry. In the past two decades, thanks to significant improvements in instrumentation and the development of new interpretive tools, it has become increasingly important for studies of lignin. This chapter presents the three important instrumental methods-Raman spectroscopy, infrared (IR) spectroscopy, and...

  6. Ab initio Hartree-Fock and density functional theory investigations on the conformational stability, molecular structure and vibrational spectra of 5-chloro-3-(2-(4-methylpiperazin-1-yl)-2-oxoethyl)benzo[d]thiazol-2(3H)-one drug molecule.

    Science.gov (United States)

    Taşal, Erol; Kumalar, Mustafa

    2012-09-01

    In this work, the experimental and theoretical spectra of 5-chloro-3-(2-(4-methylpiperazin-1-yl)-2-oxoethyl)benzo[d]thiazol-2(3H)-one molecule (abbreviated as 5CMOT) are studied. The molecular geometry and vibrational frequencies are calculated in the ground state of molecule using ab initio Hartree-Fock (HF) and Density Function Theory (DFT) methods with 6-311++G(d,p), 6-31G++(d,p), 6-31G(d,p), 6-31G(d) and 6-31G basis sets. Three staggered stable conformers were observed on the torsional potential energy surfaces. The complete assignments were performed on the basis of the total energy distribution (TED) of the vibrational modes calculated. The comparison of the theoretical and experimental geometries of the title compound indicated that the X-ray parameters fairly well agree with the theoretically obtained values for the most stable conformer. The theoretical results showed an excellent agreement with the experimental values. The calculated HOMO and LUMO energies show that the charge transfer occurs within the molecule. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Vibrational excitation in a hydrogen volume source

    International Nuclear Information System (INIS)

    Eenshuistra, P.J.

    1989-01-01

    In this thesis the complex of processes which determines the D - or H - density in a volume source, a hydrogen discharge, is studied. D - beams are of interest for driving the current of a fusion plasma in a TOKAMAK. Densities of vibrationally excited molecules, of H atoms, and of metastable hydrogen molecules were determined using Resonance-Enhanced MultiPhoton Ionization (REMPI). An experiment in which vibrationally highly excited molecules are formed by recombination of atoms in a cold metal surface, is described. The production and destruction of vibrationally excited molecules and atoms in the discharge is discussed. The vibrational distribution for 3≤ν≤5 (ν = vibrational quantumnumber) is strongly super-thermal. This effect is more apparent at higher discharge current and lower gas pressure. The analysis with a model based on rate equations, which molecules are predominantly produced by primary electron excitation of hydrogen molecules and deexcited upon one wall collision. The atom production is compatible with dissociation of molecules by primary electrons, dissociation of molecules on the filaments, and collisions between positive ions and electrons. The electrons are predominantly destroyed by recombination on the walls. Finally the production and destruction of H - in the discharge are discussed. The density of H - in the plasma, the electron density and temperature were determined. H - extraction was measured. The ratio of the extracted H - current and the H - density in the plasma gives an indication of the drift velocity of H - in the plasma. This velocity determines the emittance of the extracted beam. It was found that the H - velocity scales with the square root of the electron temperature. The measured H - densities are compatible with a qualitative model in which dissociative attachment of plasma electrons to vibrationally excited molecules is the most important process. (author). 136 refs.; 39 figs.; 10 tabs

  8. Influence of Electron Molecule Resonant Vibrational Collisions over the Symmetric Mode and Direct Excitation-Dissociation Cross Sections of CO2 on the Electron Energy Distribution Function and Dissociation Mechanisms in Cold Pure CO2 Plasmas.

    Science.gov (United States)

    Pietanza, L D; Colonna, G; Laporta, V; Celiberto, R; D'Ammando, G; Laricchiuta, A; Capitelli, M

    2016-05-05

    A new set of electron-vibrational (e-V) processes linking the first 10 vibrational levels of the symmetric mode of CO2 is derived by using a decoupled vibrational model and inserted in the Boltzmann equation for the electron energy distribution function (eedf). The new eedf and dissociation rates are in satisfactory agreement with the corresponding ones obtained by using the e-V cross sections reported in the database of Hake and Phelps (H-P). Large differences are, on the contrary, found when the experimental dissociation cross sections of Cosby and Helm are inserted in the Boltzman equation. Comparison of the corresponding rates with those obtained by using the low-energy threshold energy, reported in the H-P database, shows differences up to orders of magnitude, which decrease with the increasing of the reduced electric field. In all cases, we show the importance of superelastic vibrational collisions in affecting eedf and dissociation rates either in the direct electron impact mechanism or in the pure vibrational mechanism.

  9. Estudio de la autosuficiencia energética de una vivienda unifamiliar

    OpenAIRE

    Zeggaf, Itimad

    2015-01-01

    El título del proyecto es “Estudio de la autosuficiencia energética de una vivienda unifamiliar”. Una vivienda energéticamente autosuficiente no puede depender de ningún tipo de compañía para satisfacer las necesidades energéticas del usuario. Este proyecto estudia las necesidades energéticas de una vivienda unifamiliar habitada por 4 personas, planteando una solución que abastezca sus necesidades energéticas mediante las energías renovables. También se estudia el aprovechamiento del agua ...

  10. La energía que requiere nuestro territorio

    OpenAIRE

    Pacheco, Máximo

    2015-01-01

    En esta columna de opinión, el Ministro de Energía nos invita a enfrentarnos a un problema crucial para un país como Chile: sin energía a precios razonables, esa desigualdad social que tanto criticamos terminará por expandirse. Pero a la vez el Ministro nos invita a cambiar el foco, y así «transformar la energía en un ecualizador de la igualdad», con un Estado más activo en la solución de esta crucial problemática. In this op-ed piece, the Minister of Energy invites us to face a crucial pr...

  11. Control Operator for the Two-Dimensional Energized Wave Equation

    Directory of Open Access Journals (Sweden)

    Sunday Augustus REJU

    2006-07-01

    Full Text Available This paper studies the analytical model for the construction of the two-dimensional Energized wave equation. The control operator is given in term of space and time t independent variables. The integral quadratic objective cost functional is subject to the constraint of two-dimensional Energized diffusion, Heat and a source. The operator that shall be obtained extends the Conjugate Gradient method (ECGM as developed by Hestenes et al (1952, [1]. The new operator enables the computation of the penalty cost, optimal controls and state trajectories of the two-dimensional energized wave equation when apply to the Conjugate Gradient methods in (Waziri & Reju, LEJPT & LJS, Issues 9, 2006, [2-4] to appear in this series.

  12. Spatially Localized Particle Energization by Landau Damping in Current Sheets

    Science.gov (United States)

    Howes, G. G.; Klein, K. G.; McCubbin, A. J.

    2017-12-01

    Understanding the mechanisms of particle energization through the removal of energy from turbulent fluctuations in heliospheric plasmas is a grand challenge problem in heliophysics. Under the weakly collisional conditions typical of heliospheric plasma, kinetic mechanisms must be responsible for this energization, but the nature of those mechanisms remains elusive. In recent years, the spatial localization of plasma heating near current sheets in the solar wind and numerical simulations has gained much attention. Here we show, using the innovative and new field-particle correlation technique, that the spatially localized particle energization occurring in a nonlinear gyrokinetic simulation has the velocity space signature of Landau damping, suggesting that this well-known collisionless damping mechanism indeed actively leads to spatially localized heating in the vicinity of current sheets.

  13. Energía Minihidráulica

    OpenAIRE

    Mancebo Piqueras, José Antonio; Adrada Guerra, Teodoro; Martinez, Carmen

    2013-01-01

    La energía basada en turbinas hidráulicas de reducida potencia es, a menudo, un ejemplo- modelo dentro del campo de las energías renovables desde su aparición a finales del S. XIX, aunque los ingenios precursores surgen mucho antes. Entre los testimonios más antiguos destacan la saqia o rueda persa y la rueda hidráulica romana que había sido previamente implementada en Extremo Oriente, y que después llega a Europa a través de Egipto. Más tarde, durante la Edad Media y el Renacimiento, se gene...

  14. Energía y cambio climático

    OpenAIRE

    Wilfredo Bulege Gutiérrez

    2014-01-01

    Es claro que el crecimiento de la población, la extracción de materiales, la producción alimentaria y el incremento de energía para todas las actividades humanas nos conducen a un estado de colisión con las capacidades de la biosfera y los ecosistemas en el proceso de asegurar la provisión de bienes y servicios indispensables para la vida (1). La producción de energía convencional y contaminante es hoy una de las más graves en este escenario, tanto que la comunidad internacional y las potenci...

  15. Panorama energético mundial y argentino

    OpenAIRE

    Guadagni, Alieto

    2007-01-01

    Estamos transitando aceleradamente de una etapa caracterizada por energía abundante, barata y exportada a otra etapa signada por la escasez, el alto costo y las importaciones. Esta es la triple tenaza energética que enfrenta la Argentina. Los actuales precios del petróleo están impulsando la producción de biocombustibles (biodiesel y etanol) en Brasil, la Unión Europea y los Estados Unidos, pero también muchos otros países como el nuestro. Se estima que su participación en el consumo mundi...

  16. Molecule nanoweaver

    Science.gov (United States)

    Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

    2009-03-10

    A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

  17. Energía y cambio climático

    Directory of Open Access Journals (Sweden)

    Wilfredo Bulege Gutiérrez

    2014-06-01

    Full Text Available Es claro que el crecimiento de la población, la extracción de materiales, la producción alimentaria y el incremento de energía para todas las actividades humanas nos conducen a un estado de colisión con las capacidades de la biosfera y los ecosistemas en el proceso de asegurar la provisión de bienes y servicios indispensables para la vida (1. La producción de energía convencional y contaminante es hoy una de las más graves en este escenario, tanto que la comunidad internacional y las potencias ya han empezado a dar muestras de preocupación por la seguridad energética y, con ello por la amenaza del cambio climático. En el actual cambio climático por primera vez se viene demostrando que la humanidad ha cambiado decisivamente un ciclo liberando CO2 a la atmósfera a través de la quema de combustibles fósiles y cambios en el uso del suelo por más de 500 000 años. El origen del cambio climático se remonta a dos grandes transformaciones en el uso de la energía. En primer lugar, la energía hidráulica fue reemplazada por el carbón, una fuente de energía condensada por la naturaleza a lo largo de millones de años. Fue el aprovechamiento del carbón para nuevas tecnologías lo que propulsó la revolución industrial y desató aumentos sin precedentes en la productividad. La segunda gran transformación ocurrió 150 años más tarde. El petróleo había sido una fuente de energía humana durante milenios. En China, por ejemplo, se registran pozos petroleros ya en el siglo IV. No obstante, la utilización del petróleo para los motores de combustión interna a comienzos del siglo XX marcó el inicio de una revolución en el transporte. La quema de carbón y petróleo, junto con el gas natural, ha transformado a las sociedades humanas al proveerle la energía impulsora de grandes aumentos en la riqueza y la productividad, pero también ha impulsado el cambio climático (2. La economía humana ha crecido vertiginosamente, se multiplic

  18. En cumplimiento con la orden ejecutiva del presidente Trump sobre la Independencia Energética

    Science.gov (United States)

    Acciones reglamentarias tomadas por la EPA, incluyendo audiencias públicas, para implementar la Orden Ejecutiva sobre la Independencia Energética y la propuesta derogación del Plan de Energía Limpia.

  19. Electron-molecule collisions

    International Nuclear Information System (INIS)

    Shimamura, I.; Takayanagi, K.

    1984-01-01

    The study of collision processes plays an important research role in modern physics. Many significant discoveries have been made by means of collision experiments. Based on theoretical, experimental, and computational studies, this volume presents an overview detailing the basic processes of electron-molecule collisions. The editors have collected papers-written by a group of international experts-that consider a diverse range of phenomena occurring in electronmolecule collisions. The volume discusses first the basic formulation for scattering problems and then gives an outline of the physics of electron-molecule collisions. The main topics covered are rotational transitions, vibrational transitions, dissociation of molecules in slow collisions, the electron-molecule collision as a spectroscopic tool for studying molecular electronic structures, and experimental and computational techniques for determining the cross sections. These well-referenced chapters are self-contained and can be read independently or consecutively. Authoritative and up-to-date, Electron-Molecule Collisions is a useful addition to the libraries of students and researchers in the fields of atomic, molecular, and chemical physics, and physical chemistry

  20. The First Quantum Theory of Molecules

    Indian Academy of Sciences (India)

    IAS Admin

    rotational energies of diatomic molecules. That theory was ... resent the intensity of light emitted by a black body as a function of ... by the vibrational motion of its parts”. Bjerrum was .... −1/4; despite the fact that no molecule is a rigid rotor,.

  1. Ponte en onda: prende la energía limpia, (Spanish) Get Current

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-05-01

    Cambiar a tecnologías de energía limpia significa que fortalecemos la economía y protegemos al medio ambiente. Este libreto de actividades educativas para todas las edades promueve el uso consciente de la energía, con datos de distintas formas de energía aplicables y una variedad de rompecabezas y crucigramas en temas energéticos.

  2. La educación energética una prioridad para el milenio

    Directory of Open Access Journals (Sweden)

    Johnn Edgar Castro

    2015-01-01

    Full Text Available Este articulo plantea la necesidad  de reflexionar y trabajar en el desarrollo de propuestas sobre educación energética, desde cuatro enfoques fundamentalmente: la primera de ellas  es la inevitable dependencia de las sociedades humanas de las fuentes de energía; el ahorro energético; el agotamiento de las fuentes de energía y por ultimo las consecuencias sobre el medioambiente

  3. Zero-point vibrational effects on optical rotation

    DEFF Research Database (Denmark)

    Ruud, K.; Taylor, P.R.; Åstrand, P.-O.

    2001-01-01

    We investigate the effects of molecular vibrations on the optical rotation in two chiral molecules, methyloxirane and trans-2,3-dimethylthiirane. It is shown that the magnitude of zero-point vibrational corrections increases as the electronic contribution to the optical rotation increases....... Vibrational effects thus appear to be important for an overall estimate of the molecular optical rotation, amounting to about 20-30% of the electronic counterpart. We also investigate the special case of chirality introduced in a molecule through isotopic substitution. In this case, the zero-point vibrational...

  4. Removal of phenol from water : a comparison of energization methods

    NARCIS (Netherlands)

    Grabowski, L.R.; Veldhuizen, van E.M.; Rutgers, W.R.

    2005-01-01

    Direct electrical energization methods for removal of persistent substances from water are under investigation in the framework of the ytriD-project. The emphasis of the first stage of the project is the energy efficiency. A comparison is made between a batch reactor with a thin layer of water and

  5. Vibrational and electronic spectroscopic studies of melatonin

    Science.gov (United States)

    Singh, Gurpreet; Abbas, J. M.; Dogra, Sukh Dev; Sachdeva, Ritika; Rai, Bimal; Tripathi, S. K.; Prakash, Satya; Sathe, Vasant; Saini, G. S. S.

    2014-01-01

    We report the infrared absorption and Raman spectra of melatonin recorded with 488 and 632.8 nm excitations in 3600-2700 and 1700-70 cm-1 regions. Further, we optimized molecular structure of the three conformers of melatonin within density functional theory calculations. Vibrational frequencies of all three conformers have also been calculated. Observed vibrational bands have been assigned to different vibrational motions of the molecules on the basis of potential energy distribution calculations and calculated vibrational frequencies. Observed band positions match well with the calculated values after scaling except Nsbnd H stretching mode frequencies. It is found that the observed and calculated frequencies mismatch of Nsbnd H stretching is due to intermolecular interactions between melatonin molecules.

  6. Vibrational and Rotational Energy Relaxation in Liquids

    DEFF Research Database (Denmark)

    Petersen, Jakob

    Vibrational and rotational energy relaxation in liquids are studied by means of computer simulations. As a precursor for studying vibrational energy relaxation of a solute molecule subsequent to the formation of a chemical bond, the validity of the classical Bersohn-Zewail model for describing......, the vibrational energy relaxation of I2 subsequent to photodissociation and recombination in CCl4 is studied using classical Molecular Dynamics simulations. The vibrational relaxation times and the time-dependent I-I pair distribution function are compared to new experimental results, and a qualitative agreement...... is found in both cases. Furthermore, the rotational energy relaxation of H2O in liquid water is studied via simulations and a power-and-work analysis. The mechanism of the energy transfer from the rotationally excited H2O molecule to its water neighbors is elucidated, i.e. the energy-accepting degrees...

  7. 30 CFR 75.705-2 - Repairs to energized surface high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized surface high-voltage lines... Repairs to energized surface high-voltage lines. An energized high-voltage surface line may be repaired... on power circuits with a phase-to-phase nominal voltage no greater than 15,000 volts; (3) Such...

  8. Phosphate vibrations as reporters of DNA hydration

    Science.gov (United States)

    Corcelli, Steven

    The asymmetric phosphate stretch vibrational frequency is extraordinarily sensitive to its local solvent environment. Using density functional theory calculations on the model compound dimethyl phosphate, the asymmetric phosphate stretch vibrational frequency was found to shift linearly with the magnitude of an electric field along the symmetry axis of the PO2 moiety (i.e. the asymmetric phosphate stretch is an excellent linear vibrational Stark effect probe). With this linear relationship established, asymmetric phosphate stretch vibrational frequencies were computed during the course of a molecular dynamics simulation of fully hydrated DNA. Moreover, contributions to shifts in the frequencies from subpopulations of water molecules (e.g. backbone, minor groove, major groove, etc.) were calculated to reveal how phosphate vibrations report the onset of DNA hydration in experiments that vary the relative humidity of non-condensing (dry) DNA samples.

  9. Systematic vibration thermodynamic properties of bromine

    Science.gov (United States)

    Liu, G. Y.; Sun, W. G.; Liao, B. T.

    2015-11-01

    Based on the analysis of the maturity and finiteness of vibrational levels of bromine molecule in ground state and evaluating the effect on statistical computation, according to the elementary principles of quantum statistical theorem, using the full set of bromine molecular vibrational levels determined with algebra method, the statistical contribution for bromine systematical macroscopic thermodynamic properties is discussed. Thermodynamic state functions Helmholtz free energy, entropy and observable vibration heat capacity are calculated. The results show that the determination of full set of vibrational levels and maximum vibrational quantum number is the key in the correct statistical analysis of bromine systematical thermodynamic property. Algebra method results are clearly different from data of simple harmonic oscillator and the related algebra method results are no longer analytical but numerical and are superior to simple harmonic oscillator results. Compared with simple harmonic oscillator's heat capacities, the algebra method's heat capacities are more consistent with the experimental data in the given temperature range of 600-2100 K.

  10. Catalytic synthesis of ammonia using vibrationally excited nitrogen

    DEFF Research Database (Denmark)

    Henriksen, Niels Engholm; Billing, Gert D.; Hansen, Flemming Yssing

    1992-01-01

    In a previous study we have considered the catalytic synthesis of ammonia in the presence of vibrationally excited nitrogen. The distribution over vibrational states was assumed to be maintained during the reaction, and it was shown that the yield of ammonia increased considerably compared...... to that from conventional synthesis. In the present study the nitrogen molecules are only excited at the inlet of a plug flow reactor, and the importance of vibrational relaxation is investigated. We show that vibrational excitation can give an enhanced yield of ammonia also in the situation where vibrational...

  11. A statistical approach to inelastic electron tunneling spectroscopy on fullerene-terminated molecules

    DEFF Research Database (Denmark)

    Fock, Jeppe; Sørensen, Jakob Kryger; Lörtscher, Emanuel

    2011-01-01

    We report on the vibrational fingerprint of single C(60) terminated molecules in a mechanically controlled break junction (MCBJ) setup using a novel statistical approach manipulating the junction mechanically to address different molecular configurations and to monitor the corresponding vibration...

  12. Estudio energético del sistema eléctrico en Ecuador. Impulso a la Energía Solar Fotovoltaica

    OpenAIRE

    Eras Almeida, Andrea Alejandra

    2012-01-01

    La realización de este proyecto en base a la legislación que promueve el desarrollo de la energía limpia, pretende mostrar los cambios que tendrá la matriz energética del Ecuador si se impone un aporte renovable a la producción de energía y sus beneficios con sus futuros proyectos emblemáticos. Así también, pretende el impulso a la energía solar fotovolataica a nivel de construcciones fijas, con inversión privada y para beneficio de la sociedad misma.

  13. Evaluación del potencial energético del oleaje en Madagascar

    OpenAIRE

    Araujo Roso, Giovanni

    2017-01-01

    La energía undimotriz, o energía del oleaje, es aquella que aprovecha la energía cinética de la perturbación de la superficie del mar y está considerada como una fuente de gran potencial. Las ventajas de este tipo de recurso respecto a otras energías renovables son variadas: sus eventos son predecibles con detalle, el despliegue de dispositivos tiene un impacto visual inferior a otros y es un recurso inagotable, entre otros. Por otra parte, el campo de la energía del oleaje se ...

  14. Sistema de Aprovechamiento de la Energía de las Olas del Mar

    OpenAIRE

    Pi Amorós, Gabriel

    2010-01-01

    Este documento describe un sistema de aprovechamiento de la energía transportada por el oleaje o energía undimotriz. El sistema no transformará la energía únicamente en electricidad si no que aprovecha dicha electricidad para producir hidrógeno mediante el proceso de la electrólisis del agua de mar. Es decir, el sistema propuesto es un sistema de generación de hidrógeno de origen renovable a partir de una fuente de energía renovable, la energía undimotriz. Las característica...

  15. Hot Ground Vibration Tests

    Data.gov (United States)

    National Aeronautics and Space Administration — Ground vibration tests or modal surveys are routinely conducted to support flutter analysis for subsonic and supersonic vehicles. However, vibration testing...

  16. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 4. Molecule Matters – van der Waals Molecules - History and Some Perspectives on Intermolecular Forces. E Arunan. Feature Article Volume 14 Issue 4 April 2009 pp 346-356 ...

  17. Theory of vibration protection

    CERN Document Server

    Karnovsky, Igor A

    2016-01-01

    This text is an advancement of the theory of vibration protection of mechanical systems with lumped and distributed parameters. The book offers various concepts and methods of solving vibration protection problems, discusses the advantages and disadvantages of different methods, and the fields of their effective applications. Fundamental approaches of vibration protection, which are considered in this book, are the passive, parametric and optimal active vibration protection. The passive vibration protection is based on vibration isolation, vibration damping and dynamic absorbers. Parametric vibration protection theory is based on the Shchipanov-Luzin invariance principle. Optimal active vibration protection theory is based on the Pontryagin principle and the Krein moment method. The book also contains special topics such as suppression of vibrations at the source of their occurrence and the harmful influence of vibrations on humans. Numerous examples, which illustrate the theoretical ideas of each chapter, ar...

  18. Dissociation Energies of Diatomic Molecules

    International Nuclear Information System (INIS)

    Qun-Chao, Fan; Wei-Guo, Sun

    2008-01-01

    Molecular dissociation energies of 10 electronic states of alkali molecules of KH, 7 LiD, 7 LiH, 6 LiH, NaK, NaLi and NaRb are studied using the highest three accurate vibrational energies of each electronic state, and an improved parameter-free analytical formula which is obtained starting from the LeRoy–Bernstein vibrational energy expression near the dissociation limit. The results show that as long as the highest three vibrational energies are accurate, the current analytical formula will give accurate theoretical dissociation energies D e theory , which are in excellent agreement with the experimental dissociation energies D e expt . (atomic and molecular physics)

  19. Energy redistribution in diatomic molecules on surfaces

    International Nuclear Information System (INIS)

    Asscher, M.; Somorjai, G.A.

    1984-04-01

    Translational and internal degrees of freedom of a scattered beam of NO molecules from a Pt(111) single crystal surface were measured as a function of scattering angle and crystal temperature in the range 450 to 1250K. None of the three degrees of freedom were found to fully accommodate to the crystal temperature, the translational degree being the most accommodated and the rotational degree of freedom the least. A precursor state model is suggested to account for the incomplete accommodation of translational and vibrational degrees of freedom as a function of crystal temperature and incident beam energy. The vibrational accommodation is further discussed in terms of a competition between desorption and vibrational excitation processes, thus providing valuable information on the interaction between vibrationally excited molecules and surfaces. Energy transfer into rotational degrees of freedom is qualitatively discussed

  20. Analysis of experimental positron-molecule binding energies

    International Nuclear Information System (INIS)

    Danielson, J R; Surko, C M; Young, J A

    2010-01-01

    Experiments show that positron annihilation on molecules frequently occurs via capture into vibrational Feshbach resonances. In these cases, the downshifts in the annihilation spectra from the vibrational mode spectra provide measures of the positron-molecule binding energies. An analysis of these binding energy data is presented in terms of the molecular dipole polarizability, the permanent dipole moment, and the number of π bonds in aromatic molecules. The results of this analysis are in reasonably good agreement with other information about positron-molecule bound states. Predictions for other targets and promising candidate molecules for further investigation are discussed.

  1. Pick-up ion energization at the termination shock

    Energy Technology Data Exchange (ETDEWEB)

    Gary, S Peter [Los Alamos National Laboratory; Winske, Dan [Los Alamos National Laboratory; Wu, Pin [BOSTON UNIV.; Schwadron, N A [BOSTON UNIV.

    2009-01-01

    One-dimensional hybrid simulations are used to investigate how pickup ions are energized at the perpendicular termination shock. Contrary to previous models based on pickup ion energy gain by repeated crossings of the shock front (shock surfing) or due to a reforming shock front, the present simulations show that pickup ion energy gain involves a gyro-phasedependent interaction with the inhomogeneous motional electric field at the shock. The process operates at all relative concentrations of pickup ion density.

  2. Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization

    Science.gov (United States)

    Daglis, I.; Balasis, G.; Bourdarie, S.; Horne, R.; Khotyaintsev, Y.; Mann, I.; Santolik, O.; Turner, D.; Anastasiadis, A.; Georgiou, M.; Giannakis, O.; Papadimitriou, C.; Ropokis, G.; Sandberg, I.; Angelopoulos, V.; Glauert, S.; Grison, B., Kersten T.; Kolmasova, I.; Lazaro, D.; Mella, M.; Ozeke, L.; Usanova, M.

    2013-09-01

    We present the concept, objectives and expected impact of the MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Loss and Energization) project, which is being implemented by a consortium of seven institutions (five European, one Canadian and one US) with support from the European Community's Seventh Framework Programme. The MAARBLE project employs multi-spacecraft monitoring of the geospace environment, complemented by ground-based monitoring, in order to analyze and assess the physical mechanisms leading to radiation belt particle energization and loss. Particular attention is paid to the role of ULF/VLF waves. A database containing properties of the waves is being created and will be made available to the scientific community. Based on the wave database, a statistical model of the wave activity dependent on the level of geomagnetic activity, solar wind forcing, and magnetospheric region will be developed. Multi-spacecraft particle measurements will be incorporated into data assimilation tools, leading to new understanding of the causal relationships between ULF/VLF waves and radiation belt dynamics. Data assimilation techniques have been proven as a valuable tool in the field of radiation belts, able to guide 'the best' estimate of the state of a complex system. The MAARBLE (Monitoring, Analyzing and Assessing Radiation Belt Energization and Loss) collaborative research project has received funding from the European Union’s Seventh Framework Programme (FP7-SPACE-2011-1) under grant agreement no. 284520.

  3. Tunnel magnetoresistance of magnetic molecules with spin-vibron coupling

    Directory of Open Access Journals (Sweden)

    Ahmed Kenawy

    2017-05-01

    Full Text Available The effect of molecular vibrations on the tunnel magnetoresistance (TMR of a magnetic tunnel junction with a single spin-anisotropic molecule interconnecting its electrodes is investigated theoretically. We demonstrate that if these vibrations couple at the same time to the charge of tunneling electrons and to the spin of the molecule, the spin anisotropy of such a molecule becomes enhanced. This has, in turn, a profound impact on the TMR of such a device showing that molecular vibrations lead to a significant change of spin-polarized transport, differing for the parallel and antiparallel magnetic configuration of the junction.

  4. Atkins' molecules

    CERN Document Server

    Atkins, Peters

    2003-01-01

    Originally published in 2003, this is the second edition of a title that was called 'the most beautiful chemistry book ever written'. In it, we see the molecules responsible for the experiences of our everyday life - including fabrics, drugs, plastics, explosives, detergents, fragrances, tastes, and sex. With engaging prose Peter Atkins gives a non-technical account of an incredible range of aspects of the world around us, showing unexpected connections, and giving an insight into how this amazing world can be understood in terms of the atoms and molecules from which it is built. The second edition includes dozens of extra molecules, graphical presentation, and an even more accessible and enthralling account of the molecules themselves.

  5. Interstellar Molecules

    Science.gov (United States)

    Solomon, Philip M.

    1973-01-01

    Radioastronomy reveals that clouds between the stars, once believed to consist of simple atoms, contain molecules as complex as seven atoms and may be the most massive objects in our Galaxy. (Author/DF)

  6. Filming the Birth of Molecules and Accompanying Solvent Rearrangement

    DEFF Research Database (Denmark)

    Lee, Jae Hyuk; Wulff, Michael; Bratos, Savo

    2013-01-01

    Molecules are often born with high energy and large-amplitude vibrations. In solution, a newly formed molecule cools down by transferring energy to the surrounding solvent molecules. The progression of the molecular and solute−solvent cage structure during this fundamental process has been elusiv...

  7. Vibrational spectroscopy of SnBr4 and CCl4 using Lie algebraic ...

    Indian Academy of Sciences (India)

    experimentalists because of the development of new laser spectroscopic techniques. Wulfman played a ... used Lie algebraic methods to study the spectra of molecules (vibron model) using. U(4) algebra. ..... to vibrations of gas molecules.

  8. Vibration of machine

    International Nuclear Information System (INIS)

    Kwak, Mun Gyu; Na, Sung Su; Baek, Gwang Hyeon; Song, Chul Gi; Han, Sang Bo

    2001-09-01

    This book deals with vibration of machine which gives descriptions of free vibration using SDOF system, forced vibration using SDOF system, vibration of multi-degree of freedom system like introduction and normal form, distribution system such as introduction, free vibration of bar and practice problem, approximate solution like lumped approximations and Raleigh's quotient, engineering by intuition and experience, real problem and experimental method such as technology of signal, fourier transform analysis, frequency analysis and sensor and actuator.

  9. Exotic helium molecules

    International Nuclear Information System (INIS)

    Portier, M.

    2007-12-01

    We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range 4 He 2 (2 3 S 1 -2 3 P 0 ) molecule, or a 4 He 2 (2 3 S 1 -2 3 S 1 ) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 ± 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range 4 He 2 (2 3 S 1 -2 3 S 1 ) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime τ = (1.4 ± 0.3) μs is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

  10. Vibrational polarizabilities of hydrogen-bonded water

    International Nuclear Information System (INIS)

    Torii, Hajime

    2013-01-01

    Highlights: ► Vibrational polarizabilities of hydrogen-bonded water are analyzed theoretically. ► Total vibrational polarizability is (at least) comparable to the electronic one. ► Molecular translations contribute to the vibrational polarizability below 300 cm −1 . ► Intermolecular charge fluxes along H bonds are induced by molecular translations. ► The results are discussed in relation to the observed dielectric properties. - Abstract: The vibrational polarizabilities and the related molecular properties of hydrogen-bonded water are analyzed theoretically, taking the case of (water) 30 clusters as an example case. It is shown that some off-diagonal dipole derivatives are large for the translations of incompletely hydrogen-bonded molecules, and this is reasonably explained by the scheme of intermolecular charge fluxes induced along hydrogen bonds. In total, because of these intermolecular charge fluxes, molecular translations give rise to the vibrational polarizability of 2.8–3.3 a 0 3 per molecule, which is as large as about 40% of the electronic polarizability, mainly in the frequency region below 300 cm −1 . Adding the contributions of the molecular rotations (librations) and the translation–rotation cross term, the total polarizability (electronic + vibrational) at ∼100 cm −1 is slightly larger than the double of that at >4000 cm −1 . The relation of these results to some observed time- and frequency-dependent dielectric properties of liquid water is briefly discussed

  11. Enhanced vibration diagnostics using vibration signature analysis

    International Nuclear Information System (INIS)

    Ahmed, S.; Shehzad, K.; Zahoor, Y.; Mahmood, A.; Bibi, A.

    2001-01-01

    Symptoms will appear in equipment, as well as in human beings. when 'suffering from sickness. Symptoms of abnormality in equipment are vibration, noise, deformation, temperature, pressure, electric current, crack, wearing, leakage etc. these are called modes of failure. If the mode of failure is vibration then the vibration signature analysis can be effectively used in order to diagnose the machinery problems. Much valuable information is contained within these vibration 'Spectra' or 'Signatures' but is only of use if the analyst can unlock its 'Secrets'. This paper documents a vibration problem in the motor of a centrifugal pump (Type ETA). It focuses mainly on the roll of modern vibration monitoring system in problem analysis. The problem experienced was the motor unstability and noise due to high vibration. Using enhanced vibration signature data, the problem was analyzed. which suggested that the rotor eccentricity was the cause of excessive noise and vibration in the motor. In conclusion, advanced electronic monitoring and diagnostic systems provide powerful information for machine's condition assessment and problem analysis. Appropriate interpretation and use of this information is important for accurate and effective vibration analysis. (author)

  12. Optimal control of vibrational transitions of HCl

    Indian Academy of Sciences (India)

    Control of fundamental and overtone transitions of a vibration are studied for the diatomic molecule, HCl. Specifically, the results of the effect of variation of the penalty factor on the physical attributes of the system (i.e., probabilities) and pulse (i.e., amplitudes) considering three different pulse durations for each value of the ...

  13. Adhesion molecules

    CERN Document Server

    Preedy, Victor R

    2016-01-01

    This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

  14. Elastic and inelastic vibrational cross sections for positron scattering by carbon monoxide

    Energy Technology Data Exchange (ETDEWEB)

    Tenfen, W. [Departamento de Física, Universidade Federal da Fronteira Sul, 85770-000, Realeza, Paraná (Brazil); Arretche, F., E-mail: fartch@gmail.com [Departamento de Física, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina (Brazil); Michelin, S.E.; Mazon, K.T. [Departamento de Física, Universidade Federal de Santa Catarina, 88040-900, Florianópolis, Santa Catarina (Brazil)

    2015-11-01

    The vibrational cross sections of the CO molecule induced by positron impact is the focus of this work. The positron–molecule interaction is represented by the static potential plus a model potential designed to take into account the positron–target correlations. To calculate the vibrational cross sections, we applied the multichannel version of the continued fractions method in the close-coupling scheme. We present vibrational excitation cross sections and elastic ones, for the ground and excited vibrational states. The results are interpreted in terms of the vibrational coupling-scheme used in the scattering model.

  15. [Occupational standing vibration rate and vibrational diseases].

    Science.gov (United States)

    Karnaukh, N G; Vyshchipan, V F; Haumenko, B S

    2003-12-01

    Occupational standing vibration rate is proposed in evaluating a degree of impairment of an organism activity. It will allow more widely to introduce specification of quality and quantity in assessment of the development of vibrational disease. According out-patient and inpatient obtained data we have established criterial values of functional changes in accordance with accumulated occupational standing vibration rate. The nomogram was worked out for defining a risk of the development of vibrational disease in mine workers. This nomogram more objectively can help in diagnostics of the disease.

  16. La energía humana el esfuerzo físico

    Directory of Open Access Journals (Sweden)

    Luis Suárez Flórez

    1991-01-01

    Full Text Available Se llama la atención sobre la energía humana, su importancia como elemento de productividad y como principio ó quizás como fin de la actividad deportiva. Se estudia el máximo esfuerzo físico, así como también algunos conceptos acerca de la energía aeróbica y la energía anaeróbica.

  17. Energization of Long HVAC Cables in Parallel - Analysis and Estimation Formulas

    DEFF Research Database (Denmark)

    Silva, Filipe Faria Da; Bak, Claus Leth

    2012-01-01

    The installation of long HVAC cables has recently become more common and it tends to increase during the next years. Consequently, the energization of long HVAC cables in parallel is also a more common condition. The energization of HVAC cables in parallel resembles the en-ergization of capacitor...... has several simplifications and does not always provide accurate results. This paper proposes a new formula that can be used for the estimation of these two quantities for two HVAC cables in parallel....

  18. 30 CFR 77.704-2 - Repairs to energized high-voltage lines.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Repairs to energized high-voltage lines. 77.704... UNDERGROUND COAL MINES Grounding § 77.704-2 Repairs to energized high-voltage lines. An energized high-voltage... repairs will be performed on power circuits with a phase-to-phase nominal voltage no greater than 15,000...

  19. Observation of pendular butterfly Rydberg molecules

    Science.gov (United States)

    Niederprüm, Thomas; Thomas, Oliver; Eichert, Tanita; Lippe, Carsten; Pérez-Ríos, Jesús; Greene, Chris H.; Ott, Herwig

    2016-01-01

    Engineering molecules with a tunable bond length and defined quantum states lies at the heart of quantum chemistry. The unconventional binding mechanism of Rydberg molecules makes them a promising candidate to implement such tunable molecules. A very peculiar type of Rydberg molecules are the so-called butterfly molecules, which are bound by a shape resonance in the electron–perturber scattering. Here we report the observation of these exotic molecules and employ their exceptional properties to engineer their bond length, vibrational state, angular momentum and orientation in a small electric field. Combining the variable bond length with their giant dipole moment of several hundred Debye, we observe counter-intuitive molecules which locate the average electron position beyond the internuclear distance. PMID:27703143

  20. Energía Undimotriz, alternativa para la producción de Energía Eléctrica en la Provincia de Santa Elena

    Directory of Open Access Journals (Sweden)

    Rolando Calero

    2015-10-01

    Full Text Available La energía undimotriz, es la energía que permite obtener electricidad a partir de energía mecánica generada por el movimiento de las olas. Es uno de los tipos de energías renovables con más recientes estudios, y presenta enormes ventajas frente a otras energías renovables debido a que se tendría mayor facilidad para predecir condiciones geológicas óptimas que permitan la mayor eficiencia en sus procesos. Debido a que es más fácil llegar a predecir condiciones óptimas de oleaje, en comparación con la obtenida con  los vientos para obtener energía eólica, donde su variabilidad es menor.En este trabajo se espera aportar y dilucidar con datosespecíficos sobre la morfología de la zonamarítima en la provincia de Santa Elena, tratando depredecir si las características propias del lugar son idóneas  para producir electricidad en base a la implementación de energíaundimotriz, como fuente renovable no convencional utilizando las tecnologías actuales para este propósito.

  1. Obtención de energía a partir de las corrientes marinas

    OpenAIRE

    Echeverría Cabodevilla, Álvaro

    2017-01-01

    El objetivo del proyecto es evaluar la viabilidad de una granja de energía hidrocinética en los territorios marinos españoles. Como se puede observar en el desarrollo del estudio, el resultado es negativo. En España no existe una gran zona que pueda ser utilizada para crear una granja de energía hidrocinética. La energía hidrocinética es aquella que utiliza la energía cinética del agua marina para obtener electricidad, principalmente los movimientos de agua de las corrientes ma...

  2. Auditoría energética en una planta de tratamiento de agua potable

    OpenAIRE

    Díaz Álvarez, Silvino

    2012-01-01

    En el panorama energético actual, con las recientes incertidumbres asociadas a los precios de la energía y las inestabilidades políticas en algunos países exportadores de hidrocarburos, reducir el consumo energético mediante tecnologías más eficientes es fundamental en la definición de nuevos usos de la energía en nuestra sociedad. Dada la actual coyuntura medioambiental, económica y social, hemos de encontrar un nuevo modelo de desarrollo sostenible, incrementando la productividad de nuestra...

  3. La Demanda Residencial por Energía Eléctrica en Chile

    OpenAIRE

    Claudio A Agostini; Cecilia Plottier; Eduardo Saavedra

    2011-01-01

    En un contexto de demanda creciente y oferta estocástica de energía en Chile se hace necesario conocer a cabalidad los determinantes de la demanda por energía eléctrica de los hogares - en particular su elasticidad precio - para así utilizar mecanismos de flexibilización de precios con miras a reducir posibles déficits de energía. Este trabajo estima la demanda de energía eléctrica residencial usando información de la Encuesta de Caracterización Socioeconómica Nacional (CASEN) 2006, siendo in...

  4. Medidas de mejora de la eficiencia energética de edificios residenciales

    OpenAIRE

    Hernández Sánchez, Juan Manuel

    2012-01-01

    El parque de edificios residenciales existente tiene un potencial muy grande para mejorar la eficiencia energética a corto y medio plazo, debido al gran número de viviendas existentes y a su larga vida residual. Los factores que influyen directamente en el consumo energético y en las emisiones asociadas a los edificios residenciales son: la envolvente térmica, la eficiencia energética de los equipos, las fuentes energéticas utilizadas y el comportamiento de los usuarios. Las barreras qu...

  5. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 16; Issue 12. Molecule Matters - Dinitrogen. A G Samuelson J Jabadurai. Volume 16 Issue 12 ... Author Affiliations. A G Samuelson1 J Jabadurai1. Department of Inroganic and Physical Chemistry, Indian Institute of Science, Bangalore 560 012, India.

  6. Molecule Matters

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 9. Molecule Matters - A Chromium Compound with a Quintuple Bond. K C Kumara Swamy. Feature Article Volume 11 Issue 9 September 2006 pp 72-75. Fulltext. Click here to view fulltext PDF. Permanent link:

  7. Laser diagnostics of high vibrational and rotational H2-states

    International Nuclear Information System (INIS)

    Mosbach, Th.; Schulz-von der Gathen, V.; Doebele, H.F.

    2002-01-01

    We report on measurements of vibrational and rotational excited electronic-ground-state hydrogen molecules in a magnetic multipole plasma source by LIF with VUV radiation. The measurements are taken after rapid shut-off of the discharge current. Absolute level populations are obtained using Rayleigh scattering calibration with Krypton. The theoretically predicted suprathermal population of the vibrational distribution is clearly identified. We found also non-Boltzmann rotational distributions for the high vibrational states. The addition of noble gases (Argon and Xenon) to hydrogen leads to a decrease of the vibrational population. (Abstract Copyright [2002], Wiley Periodicals, Inc.)

  8. Importancia de las energías renovables en la seguridad energética y su relación con el crecimiento económico.

    Directory of Open Access Journals (Sweden)

    Lilian Paola Umbarila Valencia

    2015-12-01

    Full Text Available La creciente demanda de las necesidades sociales a nivel global, impulsada por los hábitos de vida y la forma en la que se organizan las regiones ha llevado al crecimiento paralelo de la industria y con ello al creciente aumento del consumo de energía. Este artículo de investigación reflexiona acerca de la relevancia que tienen las energías renovables para la seguridad energética, teniendo en cuenta la inestabilidad de los precios del petróleo y su influencia en el mercado de los hidrocarburos como fuente primaria de energía. Se evidencian los avances que han tenido las tecnologías de energías renovables a nivel global, regional y local y el rol que juegan en la independencia energética y en la mitigación del impacto ambiental. Se concluye que las naciones deben buscar la optimización de las energías renovables desde los ámbitos: local, regional y global propendiendo por su uso adecuado desde la legislación. El futuro de las energías renovables está dado por la rentabilidad, ya que para que el uso de éstas siga creciendo, deben seguir atrayendo capital lo cual significa que los inversores deben ver una rentabilidad competitiva. Otra recomendación importante es la integración de la energía renovable en la red, incluyendo fuentes de generación intermitentes e incluso imprevisibles. 

  9. Radiation signatures from a locally energized flaring loop

    Science.gov (United States)

    Emslie, A. G.; Vlahos, L.

    1980-01-01

    The radiation signatures from a locally energized solar flare loop based on the physical properties of the energy release mechanisms were consistent with hard X-ray, microwave, and EUV observations for plausible source parameters. It was found that a suprathermal tail of high energy electrons is produced by the primary energy release, and that the number of energetic charged particles ejected into the interplanetary medium in the model is consistent with observations. The radiation signature model predicts that the intrinsic polarization of the hard X-ray burst should increase over the photon energy range of 20 to 100 keV.

  10. Spin-lattice relaxation in phosphorescent triplet state molecules

    International Nuclear Information System (INIS)

    Verbeek, P.J.F.

    1979-01-01

    The present thesis contains the results of a study of spin-lattice relaxation (SLR) in the photo-excited triplet state of aromatic molecules, dissolved in a molecular host crystal. It appears that SLR in phosphorescent triplet state molecules often is related to the presence of so-called (pseudo) localized phonons in the molecular mixed crystals. These local phonons can be thought to correspond with vibrations (librations) of the guest molecule in the force field of the surrounding host molecules. Since the intermolecular forces are relatively weak, the frequencies corresponding with these vibrations are relatively low and usually are of the order of 10-30 cm -1 . (Auth.)

  11. La energía minihidráulica en los planes de fomento de las energías renovables en España

    OpenAIRE

    Espejo Marín, Cayetano; García Marín, Ramón; Aparicio Guerrero, Ana Eulalia

    2016-01-01

    La energía minihidráulica incluye las centrales con una potencia instalada de hasta 10 megavatios. Esta tecnología de producción energética se ha incluido en los Planes de Fomento de las Energías Renovables promovidos por los Gobiernos de España desde finales de los años noventa a la actualidad. En esta aportación se analizan los objetivos de potencia a instalar en cada Comunidad Autónoma durante el periodo de vigencia de cada Plan, las barreras con las que se encuentra el sector para el desa...

  12. Conocimiento de Energía: Principios Esenciales y Conceptos Fundamentales para la Educación de Energía

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-06-01

    This is the Spanish version of our Energy Literacy guidebook. Esta guía presenta conceptos de energía que, cuando se entienden y se aplican, ayudan a individuos y a comunidades a tomar decisiones sobre la energía con conocimiento de causa. No es un currículo sino que ofrece un marco sobre el cual puede basarse un plan de estudios. La guía se dirige a cualquier persona que participe en la educación de energía.

  13. Portable vibration exciter

    Science.gov (United States)

    Beecher, L. C.; Williams, F. T.

    1970-01-01

    Gas-driven vibration exciter produces a sinusoidal excitation function controllable in frequency and in amplitude. It allows direct vibration testing of components under normal loads, removing the possibility of component damage due to high static pressure.

  14. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

    We make music by causing strings, membranes, or air columns to vibrate. Engineers design safe structures by control- ling vibrations. I will describe to you a very simple vibrating system and the mathematics needed to analyse it. The ideas were born in the work of Joseph-Louis Lagrange (1736–1813), and I begin by quot-.

  15. Wireless energizing system for an automated implantable sensor

    Energy Technology Data Exchange (ETDEWEB)

    Swain, Biswaranjan; Nayak, Praveen P.; Kar, Durga P.; Bhuyan, Satyanarayan; Mishra, Laxmi P. [Department of Electronics and Instrumentation Engineering, Siksha ‘O’ Anusandhan University, Bhubaneswar 751030 (India)

    2016-07-15

    The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonant frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.

  16. Wireless energizing system for an automated implantable sensor

    International Nuclear Information System (INIS)

    Swain, Biswaranjan; Nayak, Praveen P.; Kar, Durga P.; Bhuyan, Satyanarayan; Mishra, Laxmi P.

    2016-01-01

    The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonant frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.

  17. Wireless energizing system for an automated implantable sensor.

    Science.gov (United States)

    Swain, Biswaranjan; Nayak, Praveen P; Kar, Durga P; Bhuyan, Satyanarayan; Mishra, Laxmi P

    2016-07-01

    The wireless drive of an automated implantable electronic sensor has been explored for health monitoring applications. The proposed system comprises of an automated biomedical sensing system which is energized through resonant inductive coupling. The implantable sensor unit is able to monitor the body temperature parameter and sends back the corresponding telemetry data wirelessly to the data recoding unit. It has been observed that the wireless power delivery system is capable of energizing the automated biomedical implantable electronic sensor placed over a distance of 3 cm from the power transmitter with an energy transfer efficiency of 26% at the operating resonant frequency of 562 kHz. This proposed method ensures real-time monitoring of different human body temperatures around the clock. The monitored temperature data have been compared with a calibrated temperature measurement system to ascertain the accuracy of the proposed system. The investigated technique can also be useful for monitoring other body parameters such as blood pressure, bladder pressure, and physiological signals of the patient in vivo using various implantable sensors.

  18. Seguridad energética rusa: entre Europa y China

    Directory of Open Access Journals (Sweden)

    Antonio Sánchez

    2008-05-01

    Full Text Available Dentro de la seguridad energética rusa aparece como una debilidad importante la concentración de recursos en unos pocos clientes, en concreto en la UE. Por este motivo, las autoridades rusas están tratando de diversificar destinos de venta, tratando de abrir otros mercados, en especial en extremo oriente y, en particular en China. Esto acrecienta su seguridad energética, pero debilita la europea en caso de que la UE no adopte medidas activas. El abastecimiento a Europa desde Rusia, especialmente de gas, depende también de tres grandes limitaciones. En primer lugar, que existan nuevos yacimientos y su posibilidad de movilizarlos conforme aumenten las necesidades europeas. En segundo lugar, aparece el problema del surgimiento de competidores por el gas ruso y, en particular, recientemente se ha subrayado el papel de China como futuro cliente de gas ruso. En tercer lugar, se encuentra la posibilidad de que Rusia pueda ejercer un control especial sobre la oferta de gas mundial, que condicione en cantidad o/y precio el abastecimiento a Europa.

  19. Particle energization by inertial Alfven wave in auroral ionosphere

    Science.gov (United States)

    Kumar, S.

    2017-12-01

    The role of inertial Alfven wave in auroral acceleration region and in the inertial regime to energize the plasma particles is an interesting field and widely discussed observationally as well as theoretically in recent years. In this work, we present the density perturbations by inertial Alfvén wave (AW) in the auroral ionosphere. We obtain dynamical equations for inertial AW and fast mode of AW using two-fluid model and then solve them numerically in order to analyze the localized structures and cavity formation. The ponderomotive force due to the high frequency inertial AW changes the background density and is believed to be responsible for the wave localization or for the formation of density cavities in auroral ionosphere. These density cavities are believed to be the sites for particle energization. This perturbed density channel grow with time until the modulation instability acquires steady state. We find that the density cavities are accompanied by the high amplitude magnetic fields. The amplitude of the strongest density cavity is estimated as ˜ 0.26n0 (n0 is unperturbed plasma number density). The results presented here are found consistent with the observational studies using FAST spacecraft.

  20. A new scaling algorithm for predicting vibrational spectra of ...

    Indian Academy of Sciences (India)

    Administrator

    RMS error 5 cm. –1. 4. Glycine molecule. Glycine exists as a neutral molecule in the gas phase. The vibrational spectrum of glycine in the gas phase has been studied recently by theory and experiment. 12. To check the methodology we tried. MP2/6-311++G** calculations on the most stable conformation of glycine. All the ...

  1. Trapping molecules in two and three dimensions

    International Nuclear Information System (INIS)

    Pinkse, PW.H.; Junglen, T.; Rieger, T.; Rangwala, S.A.; Windpassinger, P.; Rempe, G.

    2005-01-01

    Full text: Cold molecules offer a new testing ground for quantum-physical effects in nature. For example, producing slow beams of large molecules could push experiments studying the boundary between quantum interference and classical particles up towards ever heavier particles. Moreover, cold molecules, in particular YbF, seem an attractive way to narrow down the constraints on the value of the electron dipole moment and finally, quantum information processing using chains of cold polar molecules or vibrational states in molecules have been proposed. All these proposals rely on advanced production and trapping techniques, most of which are still under development. Therefore, novel production and trapping techniques for cold molecules could offer new possibilities not found in previous methods. Electric traps hold promise for deep trap potentials for neutral molecules. Recently we have demonstrated two-dimensional trapping of polar molecules in a four-wire guide using electrostatic and electrodynamic trapping techniques. Filled from a thermal effusive source, such a guide will deliver a beam of slow molecules, which is an ideal source for interferometry experiments with large molecules, for instance. Here we report about the extension of this work to three-dimensional trapping. Polar molecules with a positive Stark shift can be trapped in the minimum of an electrostatic field. We have successfully tested a large volume electrostatic trap for ND3 molecules. A special feature of this trap is that it can be loaded continuously from an electrostatic guide, at a temperature of a few hundred mK. (author)

  2. Electron molecule cross sections relevant to negative ion sources and divertor plasmas

    International Nuclear Information System (INIS)

    Celiberto, R.; Capitelli, M.; Lamanna, U.T.; Janev, R.K.

    1996-01-01

    Electron-molecule cross sections for electronic transitions in H 2 and D 2 molecules vibrationally excited are presented, and a scaling law for the vibrational cross sections is discussed for the X 1 summation + g →B 1 summation + u electronic transition. copyright 1996 American Institute of Physics

  3. In-situ Studies of the Reactions of Bifunctional and Heterocyclic Molecules over Noble Metal Single Crystal and Nanoparticle Catalysts Studied with Kinetics and Sum-Frequency Generation Vibrational Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kliewer, Christopher J. [Univ. of California, Berkeley, CA (United States)

    2009-06-30

    Sum frequency generation surface vibrational spectroscopy (SFG-VS) in combination with gas chromatography (GC) was used in-situ to monitor surface bound reaction intermediates and reaction selectivities for the hydrogenation reactions of pyrrole, furan, pyridine, acrolein, crotonaldehyde, and prenal over Pt(111), Pt(100), Rh(111), and platinum nanoparticles under Torr reactant pressures and temperatures of 300K to 450K. The focus of this work is the correlation between the SFG-VS observed surface bound reaction intermediates and adsorption modes with the reaction selectivity, and how this is affected by catalyst structure and temperature. Pyrrole hydrogenation was investigated over Pt(111) and Rh(111) single crystals at Torr pressures. It was found that pyrrole adsorbs to Pt(111) perpendicularly by cleaving the N-H bond and binding through the nitrogen. However, over Rh(111) pyrrole adsorbs in a tilted geometry binding through the {pi}-aromatic orbitals. A surface-bound pyrroline reaction intermediate was detected over both surfaces with SFG-VS. It was found that the ring-cracking product butylamine is a reaction poison over both surfaces studied. Furan hydrogenation was studied over Pt(111), Pt(100), 10 nm cubic platinum nanoparticles and 1 nm platinum nanoparticles. The product distribution was observed to be highly structure sensitive and the acquired SFG-VS spectra reflected this sensitivity. Pt(100) exhibited more ring-cracking to form butanol than Pt(111), while the nanoparticles yielded higher selectivities for the partially saturated ring dihydrofuran. Pyridine hydrogenation was investigated over Pt(111) and Pt(100). The α-pyridyl surface adsorption mode was observed with SFG-VS over both surfaces. 1,4-dihydropyridine was seen as a surface intermediate over Pt(100) but not Pt(111). Upon heating the surfaces to 350K, the adsorbed pyridine changes to a flat-lying adsorption mode. No evidence was found for the pyridinium cation. The hydrogenation of the

  4. Ahorre Energía: Consejos sobre el ahorro de dinero y energía en el hogar (Spanish Brochure), Energy Savers Guide

    Energy Technology Data Exchange (ETDEWEB)

    None

    2014-09-01

    La versión en castellano de la guía del Departamento de Energía de los Estados Unidos que ayuda a consumidores a ahorrar energía y dinero en el hogar y en las carreteras. The Spanish-language version of U.S. Department of Energy's consumer guide to saving energy and money at home and on the road.

  5. Ahorre Energía: Consejos para ahorro dinero y energía en su hogar (Spanish Brochure), Energy Saver Guide

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-11-01

    La versión en castellano de la guía del Departamento de Energía de los Estados Unidos que ayuda a consumidores a ahorrar energía y dinero en su hogar y en las carreteras. The Spanish-language version of U.S. Department of Energy's Energy Saver consumer guide to saving energy and money at home and on the road.

  6. El futuro energético de Japón

    Directory of Open Access Journals (Sweden)

    María Francisca Casado

    2016-05-01

    Full Text Available Tras el triple desastre del 11 de marzo de 2011, Japón se encuentra en una encrucijada energética. A corto y medio plazo depende de las importaciones de combustibles fósiles para garantizar su seguridad energética, pero el largo plazo está por decidir y lo determinarán las decisiones que tome en estos años. Como consta en su Estrategia de Seguridad Nacional, para Japón la seguridad energética es una cuestión de seguridad nacional. El artículo revisa la trayectoria nuclear nipona, estudia cuáles son los factores que configuran el mercado eléctrico japonés y analiza su actual situación energética. Por otra parte, también repasa los principios que han marcado su política energética, deteniéndose a evaluar los dos últimos Planes Estratégicos de Energía –uno anterior y otro posterior a Fukushima- antes de adentrarse en el debate sobre la composición óptima del futuro mix energético para cumplir con su trilema de la seguridad energética, marcado por su compromiso con el medio ambiente.

  7. Situación actual del sector energético en España

    Directory of Open Access Journals (Sweden)

    Carlos J. Pardo Abad

    2001-01-01

    Full Text Available La energía es un sector clave de la economía española y está presente en todos los procesos productivos. El artículo analiza al sector en los últimos años con datos procedentes de varios organismos públicos, referidos tanto al balance energético general como a los sectores energéticos, las energías renovables, la política energética y las relaciones entre energía y medio ambiente. Características básicas del sector en nuestro país son el incremento del consumo de energía, la progresiva liberalización y las grandes inversiones en energías renovables, sobre todo la eólica. Energy is a key sector of the Spanish economy and it is in all productivo processes.This article analyses the sector in the last fewyears with data from some public agencies, referred to the power balance as well as to nuclear power, coal, oil, natural gas, renewable energies, power policy and the relationship between energy and environment. The main eatures of energy in Spain are the increase of consumption, the growing liberation and the big investments in renewable energies, above all the eolic one.

  8. Modelado Energético de Convertidores Primarios para el Aprovechamiento de las Energías Renovables Marinas

    Directory of Open Access Journals (Sweden)

    Amable López

    2014-04-01

    Full Text Available Resumen: El objetivo principal de este artículo es presentar los métodos más habituales de aprovechamiento de distintos tipos de energías renovables procedentes del mar y analizar los modelos energéticos de los dispositivos utilizados para su explotación. Estos modelos son necesarios para el diseño del dispositivo así como para el estudio de su comportamiento dinámico. Su conocimiento resulta imprescindible también para su simulación dinámica y para el diseño de los algoritmos de control necesarios para conseguir una optimización energética y económica. En este trabajo se presentan algunos de los diferentes tipos de energías del mar, y se j ustifica el interés en el desarrollo de dispositivos específicos para el aprovechamiento de las corrientes marinas y de las olas, junto con una pequeña clasificación en función de la profundidad del agua en la zona de instalación de estos dispositivos. Para los convertidores de energía de las olas, generalmente, de tipo resonante, se presenta una metodología de tipo general, analizando los distintos campos de fuerzas actuantes y los métodos de obtención de las respuestas temporal y frecuencial. Para los dispositivos de aprovechamiento de las corrientes, se propone una metodología simplificada de modelado dinámico que puede ser utilizada en análisis del dispositivo concreto. Para ello se tiene en cuenta los perfiles hidrodinámicos que utilizan estos dispositivos, los datos del perfil de la corriente con la profundidad y del modelo de oleaje, y la dinámica propia del conjunto multiplicadora y generador eléctrico. La metodología propuesta se aplica al estudio de un caso concreto, correspondiente a un rotor de eje horizontal de un convertidor de energía de las corrientes. Los resultados obtenidos permiten analizar los efectos del oleaje y de las condiciones de flujo de la corriente no uniforme sobre las magnitudes energéticas más importantes. Abstract: The main objective of

  9. Vibration of hydraulic machinery

    CERN Document Server

    Wu, Yulin; Liu, Shuhong; Dou, Hua-Shu; Qian, Zhongdong

    2013-01-01

    Vibration of Hydraulic Machinery deals with the vibration problem which has significant influence on the safety and reliable operation of hydraulic machinery. It provides new achievements and the latest developments in these areas, even in the basic areas of this subject. The present book covers the fundamentals of mechanical vibration and rotordynamics as well as their main numerical models and analysis methods for the vibration prediction. The mechanical and hydraulic excitations to the vibration are analyzed, and the pressure fluctuations induced by the unsteady turbulent flow is predicted in order to obtain the unsteady loads. This book also discusses the loads, constraint conditions and the elastic and damping characters of the mechanical system, the structure dynamic analysis, the rotor dynamic analysis and the system instability of hydraulic machines, including the illustration of monitoring system for the instability and the vibration in hydraulic units. All the problems are necessary for vibration pr...

  10. Anti-vibration gloves?

    Science.gov (United States)

    Hewitt, Sue; Dong, Ren G; Welcome, Daniel E; McDowell, Thomas W

    2015-03-01

    For exposure to hand-transmitted vibration (HTV), personal protective equipment is sold in the form of anti-vibration (AV) gloves, but it remains unclear how much these gloves actually reduce vibration exposure or prevent the development of hand-arm vibration syndrome in the workplace. This commentary describes some of the issues that surround the classification of AV gloves, the assessment of their effectiveness and their applicability in the workplace. The available information shows that AV gloves are unreliable as devices for controlling HTV exposures. Other means of vibration control, such as using alternative production techniques, low-vibration machinery, routine preventative maintenance regimes, and controlling exposure durations are far more likely to deliver effective vibration reductions and should be implemented. Furthermore, AV gloves may introduce some adverse effects such as increasing grip force and reducing manual dexterity. Therefore, one should balance the benefits of AV gloves and their potential adverse effects if their use is considered. © Crown copyright 2014.

  11. Testable, fault-tolerant power interface circuit for normally de-energized loads

    International Nuclear Information System (INIS)

    Hager, R.E.

    1987-01-01

    A power interface circuit is described for supplying power from a power line to a normally de-energized process control apparatus in a pressurized light water nuclear power system in dependence upon three input signals, comprising: voter means for supplying power to the normally de-energized load when at least two of the three input signals indicate that the normally de-energized load should be activated; a normally closed switch, operatively connected to the power line and the voter means, for supplying power to the voter means during ordinary operation; a first resistor operatively connected to the power line; a current detector operatively connected to the first resistor and the voter means; a second resistor operatively connected to the current detector and ground; and current sensor means, operatively connected between the voter means and the normally de-energized load, for detecting the power supplied to the normally de-energized load by the voter means

  12. Development of varying magnetic field analysis technology caused by vibration of MRI apparatus

    International Nuclear Information System (INIS)

    Imamura, Yukinobu; Motoshiromizu, Hirofumi; Abe, Mitsushi; Watanabe, Hiroyuki; Takeuchi, Hiroyuki

    2015-01-01

    In Magnetic Resonance Imaging (MRI) apparatus, pulse current is energized to the gradient coils in a strong static magnetic field generated by the static magnetic poles. Since electromagnetic force (i.e. Lorentz force) is generated in the gradient coils, the MRI magnet system vibrates. On the other hand, vibration of the MRI magnet system is affected by electromagnetic force caused by static magnetic poles vibration. As the vibration of MRI magnet system causes magnetic field disturbance (so-called 'error magnetic field') and affect image quality, it is important to evaluate them in the design process. In this study, a varying magnetic field evaluation method for MRI magnet system was developed. Vibration and electromagnetic force is considered in the weak coupling formation using the Modal Magnetic Dumping (MMD) method. In the eddy current analysis by vibration, the displacement was considered in the magnetic field changes in the finite elements. Error magnetic field caused by equipment vibration was obtained by superposition of the static magnetic field fluctuation and the eddy current magnetic field. Then open type MRI magnet was evaluated by the proposed methodology. A a result, vibration of static magnet poles were suppressed by magnetic dumping at 50 Hz or less and eddy current magnetic field was dominant at 50 Hz or more. (author)

  13. Isotope separation by photodissociation of Van der Wall's molecules

    International Nuclear Information System (INIS)

    Lee, Y.T.

    1977-01-01

    A method of separating isotopes based on the dissociation of a Van der Waal's complex is described. A beam of molecules of a Van der Waal's complex containing, as one partner of the complex, a molecular species in which an element is present in a plurality of isotopes is subjected to radiation from a source tuned to a frequency which will selectively excite vibrational motion by a vibrational transition or through electronic transition of those complexed molecules of the molecular species which contain a desired isotope. Since the Van der Waal's binding energy is much smaller than the excitational energy of vibrational motion, the thus excited Van der Waal's complex dissociate into molecular components enriched in the desired isotope. The recoil velocity associated with vibrational to translational and rotational relaxation will send the separated molecules away from the beam whereupon the product enriched in the desired isotope can be separated from the constituents of the beam

  14. Thermal ion-molecule reactions in oxygen-containing molecules

    International Nuclear Information System (INIS)

    Kumakura, Minoru

    1981-02-01

    The energetics of ions and the thermal ion-molecule reactions in oxygen-containing molecules have been studied with a modified time-of-flight mass spectrometer. It was found that the translational energy of ion can be easily obtained from analysis of the decay curve using the time-of-flight mass spectrometer. The condensation-elimination reactions proceeded via cross- and homo-elimination mechanism in which the nature of intermediate-complex could be correlated with the nature of reactant ion. It was elucidated that behavior of poly-atomic oxygen-containing ions on the condensation-elimination reactions is considerably influenced by their oxonium ion structures having functional groups. In addition, the rate constants of the condensation-elimination reactions have affected with the energy state of reactant ion and the dipole moment and/or the polarizability of neutral molecule. It was clarified that the rate constants of the ion-molecule clustering reactions in poly-atomic oxygen-containing molecules such as cyclic ether of six member rings are very large and the cluster ions are stable owing to the large number of vibrational degree of freedom in the cluster ions. (author)

  15. Modelling of energetic molecule-surface interactions

    International Nuclear Information System (INIS)

    Kerford, M.

    2000-09-01

    This thesis contains the results of molecular dynamics simulations of molecule-surface interactions, looking particularly at fullerene molecules and carbon surfaces. Energetic impacts of fullerene molecules on graphite create defect craters. The relationship between the parameters of the impacting molecule and the parameters of the crater axe examined and found to be a function of the energy and velocity of the impacting molecule. Less energetic fullerene molecules can be scattered from a graphite surface and the partitioning of energy after a scattering event is investigated. It is found that a large fraction of the kinetic energy retained after impact is translational energy, with a small fraction of rotational energy and a number of vibrational modes. At impact energies where the surface is not broken and at normal incidence, surface waves axe seen to occur. These waves axe used to develop a method of desorbing molecules from a graphite surface without damage to either the surface or the molecules being desorbed. A number of fullerene molecules are investigated and ways to increase the desorption yield are examined. It is found that this is a successful technique for desorbing large numbers of intact molecules from graphite. This technique could be used for desorbing intact molecules into a gas phase for mass spectrometric analysis. (author)

  16. Stochastic models for surface diffusion of molecules

    Energy Technology Data Exchange (ETDEWEB)

    Shea, Patrick, E-mail: patrick.shea@dal.ca; Kreuzer, Hans Jürgen [Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Nova Scotia B3H 3J5 (Canada)

    2014-07-28

    We derive a stochastic model for the surface diffusion of molecules, starting from the classical equations of motion for an N-atom molecule on a surface. The equation of motion becomes a generalized Langevin equation for the center of mass of the molecule, with a non-Markovian friction kernel. In the Markov approximation, a standard Langevin equation is recovered, and the effect of the molecular vibrations on the diffusion is seen to lead to an increase in the friction for center of mass motion. This effective friction has a simple form that depends on the curvature of the lowest energy diffusion path in the 3N-dimensional coordinate space. We also find that so long as the intramolecular forces are sufficiently strong, memory effects are usually not significant and the Markov approximation can be employed, resulting in a simple one-dimensional model that can account for the effect of the dynamics of the molecular vibrations on the diffusive motion.

  17. Molecule Matters van der Waals Molecules

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Molecule Matters van der Waals Molecules - Noble Gas Clusters are London Molecules! E Arunan. Feature Article Volume 14 Issue 12 December 2009 pp 1210-1222 ...

  18. Por uma nova ordem energética global? potencialidades e perspectivas da questão energética entre os países BRICS

    Directory of Open Access Journals (Sweden)

    José María Gómez

    2012-12-01

    Full Text Available O presente artigo propõe analisar a questão energética entre os BRICS e o potencial de rearticulação da ordem energética global que dela emerge. Para tal, realiza três movimentos. Em primeiro lugar, investiga o crescente impacto agregado dos países BRICS no cenário energético global, com vistas a analisar seu avanço em uma temática até então reduto dos países desenvolvidos. Em segundo lugar, aborda a matriz energética de cada um dos cinco países do ponto de vista de suas economias políticas e da questão da sustentabilidade. Em terceiro lugar, e com base na seção anterior, propõe mapear as áreas de conflito e de possível aproximação entre os BRICS, na tentativa de localizar as possibilidades e limites da sua cooperação energética. Com base nessa investigação, conclui que, diante das potencialidades para a cooperação entre os países, a organização de suas ofertas e demandas energéticas nacionais pode permitir ao agrupamento articular-se como um novo polo no cenário energético global.

  19. Aplicación electrónica para el ahorro de energía eléctrica utilizando una energía alternativa

    Directory of Open Access Journals (Sweden)

    Juan Carlos Cruz-Ardila

    2013-01-01

    Full Text Available El artículo presenta un trabajo orientado a disminuir el consumo de energía eléctrica entregada por la red eléctrica convencional, a través del aprovechamiento de la energía solar fotovoltaica. Se propone el diseño de un sistema de transferencia electrónica que facilita el uso de la energía eléctrica DC proveniente del panel solar, suprimiendo de esta manera, la utilización del inversor de voltaje, comúnmente usado en este tipo de aplicaciones y que eleva el costo de utilización de la energía solar. Se da a conocer inicialmente una revisión del estado del arte, que permite contextualizar el problema resuelto a partir de una energía renovable como la fotovoltaica, destacándose que actualmente España es el país con mayor desarrollo en este tema. Luego, se muestra el desarrollo secuencial del sistema de alimentación y la transferencia electrónica, haciendo una descripción de las variables identificadas y explicación, con el uso de diagramas de flujo, del sistema embebido implementado. También se da una descripción de los dispositivos usados tal como el sensor de corriente, la regulación y la rectificación. Se muestra el esquemático de la transferencia implementada. Finalmente, se revelan los resultados y las pruebas operacionales realizadas al sistema para demostrar la funcionalidad de la aplicación electrónica en el ahorro de la energía eléctrica utilizando una energía alternativa.

  20. Electron affinities of atoms, molecules, and radicals

    International Nuclear Information System (INIS)

    Christodoulides, A.A.; McCorkle, D.L.; Christophorou, L.G.

    1982-01-01

    We review briefly but comprehensively the theoretical, semiempirical and experimental methods employed to determine electron affinities (EAs) of atoms, molecules and radicals, and summarize the EA data obtained by these methods. The detailed processes underlying the principles of the experimental methods are discussed very briefly. It is, nonetheless, instructive to recapitulate the definition of EA and those of the related quantities, namely, the vertical detachment energy, VDE, and the vertical attachment energy, VAE. The EA of an atom is defined as the difference in total energy between the ground state of the neutral atom (plus the electron at rest at infinity) and its negative ion. The EA of a molecule is defined as the difference in energy between the neutral molecule plus an electron at rest at infinity and the molecular negative ion when both, the neutral molecules and the negative ion, are in their ground electronic, vibrational and rotational states. The VDE is defined as the minimum energy required to eject the electron from the negative ion (in its ground electronic and nuclear state) without changing the internuclear separation; since the vertical transition may leave the neutral molecule in an excited vibrational/rotational state, the VDE, although the same as the EA for atoms is, in general, different (larger than), from the EA for molecules. Similarly, the VAE is defined as the difference in energy between the neutral molecule in its ground electronic, vibrational and rotational states plus an electron at rest at infinity and the molecular negative ion formed by addition of an electron to the neutral molecule without allowing a change in the intermolecular separation of the constituent nuclei; it is a quantity appropriate to those cases where the lowest negative ion state lies above the ground states of the neutral species and is less or equal to EA

  1. Producción, Reservas y Sostenibilidad de la Energía en Venezuela

    Directory of Open Access Journals (Sweden)

    Juan Carlos Rojas-Zerpa

    2015-06-01

    Full Text Available El propósito del presente trabajo está relacionado con la evaluación de los recursos energéticos de Venezuela y su posicionamiento estratégico mundial, referido principalmente a la producción y consumo de energía primaria y reservas. Así mismo se han evaluado los recursos energéticos renovables con la finalidad de identificar oportunidades para el desarrollo de la energía sostenible. Los resultados indican que Venezuela posee recursos fósiles para más de 130 años de explotación, lo cual lo convierte en una potencia energética relevante en el contexto mundial. La potencialidad aprovechable de las energías renovables duplicó la producción de recursos fósiles en 2011. En la actualidad, el aprovechamiento de estas fuentes es inferior al 2 % del total disponible, lo que deja abierto un amplio rango de posibilidades para la diversificación de la matriz energética nacional mediante tecnologías limpias o sostenibles

  2. Transfer vibration through spine

    OpenAIRE

    Benyovszky, Adam

    2012-01-01

    Transfer Vibration through Spine Abstract In the bachelor project we deal with the topic of Transfer Vibration through Spine. The problem of TVS is trying to be solved by the critical review method. We analyse some diagnostic methods and methods of treatment based on this principle. Close attention is paid to the method of Transfer Vibration through Spine that is being currently solved by The Research Institute of Thermomechanics in The Czech Academy of Sciences in cooperation with Faculty of...

  3. Anharmonic Vibrational Spectroscopy on Metal Transition Complexes

    Science.gov (United States)

    Latouche, Camille; Bloino, Julien; Barone, Vincenzo

    2014-06-01

    Advances in hardware performance and the availability of efficient and reliable computational models have made possible the application of computational spectroscopy to ever larger molecular systems. The systematic interpretation of experimental data and the full characterization of complex molecules can then be facilitated. Focusing on vibrational spectroscopy, several approaches have been proposed to simulate spectra beyond the double harmonic approximation, so that more details become available. However, a routine use of such tools requires the preliminary definition of a valid protocol with the most appropriate combination of electronic structure and nuclear calculation models. Several benchmark of anharmonic calculations frequency have been realized on organic molecules. Nevertheless, benchmarks of organometallics or inorganic metal complexes at this level are strongly lacking despite the interest of these systems due to their strong emission and vibrational properties. Herein we report the benchmark study realized with anharmonic calculations on simple metal complexes, along with some pilot applications on systems of direct technological or biological interest.

  4. Calculations on the vibrational level density in highly excited formaldehyde

    International Nuclear Information System (INIS)

    Rashev, Svetoslav; Moule, David C.

    2003-01-01

    The object of the present work is to develop a model that provides realistic estimates of the vibrational level density in polyatomic molecules in a given electronic state, at very high (chemically relevant) vibrational excitation energies. For S 0 formaldehyde (D 2 CO), acetylene, and a number of triatomics, the estimates using conventional spectroscopic formulas have yielded densities at the dissociation threshold, very much lower than the experimentally measured values. In the present work we have derived a general formula for the vibrational energy levels of a polyatomic molecule, which is a generalization of the conventional Dunham spectroscopic expansion. Calculations were performed on the vibrational level density in S 0 D 2 CO, H 2 C 2 , and NO 2 at excitation energies in the vicinity of the dissociation limit, using the newly derived formula. The results from the calculations are in reasonable agreement with the experimentally measured data

  5. Mechanisms of Coupled Vibrational Relaxation and Dissociation in Carbon Dioxide.

    Science.gov (United States)

    Armenise, Iole; Kustova, Elena

    2018-05-21

    A complete vibrational state-specific kinetic scheme describing dissociating carbon dioxide mixtures is proposed. CO 2 symmetric, bending and asymmetric vibrations and dissociation-recombination are strongly coupled through inter-mode vibrational energy transfers. Comparative study of state-resolved rate coefficients is carried out; the effect of different transitions may vary considerably with temperature. A non-equilibrium 1-D boundary layer flow typical to hypersonic planetary entry is studied in the state-to-state approach. To assess the sensitivity of fluid-dynamic variables and heat transfer to various vibrational transitions and chemical reactions, corresponding processes are successively included to the kinetic scheme. It is shown that vibrational-translational (VT) transitions in the symmetric and asymmetric modes do not alter the flow and can be neglected whereas the VT 2 exchange in the bending mode is the main channel of vibrational relaxation. Inter-mode vibrational exchanges affect the flow implicitly, through energy redistribution enhancing VT relaxation; the dominating role belongs to near-resonant transitions between symmetric and bending modes as well as between CO molecules and CO 2 asymmetric mode. Strong coupling between VT 2 relaxation and chemical reactions is emphasized. While vibrational distributions and average vibrational energy show strong dependence on the kinetic scheme, the heat flux is more sensitive to chemical reactions.

  6. La inversión en energías renovables en Argentina

    OpenAIRE

    Recalde, Marina

    2017-01-01

    En este artículo se analiza en qué medida los factores del entorno de la política energética de un país en desarrollo, tal como Argentina, determinan la evolución de la inversión en energías renovables. La baja calidad institucional del país ayuda a crear condiciones no propicias que contrarrestan el efecto de la política energética, reduciendo los incentivos para invertir en tecnologías renovables. Es necesario entonces mejorar las condiciones institucionales de los países en desarrollo para...

  7. Estudio del balance energético en velocistas de alto rendimiento

    OpenAIRE

    Lorente Gutiérrez, Jesús

    2015-01-01

    El objetivo de este estudio fue evaluar el balance energético en tres atletas de alto rendimiento durante 28 días, que coincidieron con el periodo competitivo de pista cubierta. La ingesta energética fue estudiada a partir de registros alimentarios durante los 28 días. Del mismo modo, el gasto energético fue estimado por tres métodos, mediante registros de actividad durante 28 días, mediante el estudio del ritmo metabólico basal estudiado por calorimetría indirecta, aplicándole el fa...

  8. Perspectivas de la situación energética mundial. Las oportunidades para Colombia

    OpenAIRE

    Arturo Infante Villarreal

    2007-01-01

    Casi la cuarta parte de la energía que consume Estados Unidos proviene de petróleo importado y sólo el 6% se origina en fuentes renovables, aunque el país produce 20% de la polución ambiental mundial y tiene sólo 4% de la población total. Los biocombustibles son una fuente potencial de energía renovable para Estados Unidos, y el resto del mundo, porque tienen un balance energético y ambiental bastante favorable. Si las condiciones de precios son adecuadas para los productores de las materias ...

  9. Eficiencia energética en el sector residencial de la ciudad de Cuenca, Ecuador

    OpenAIRE

    Baquero Larriva, María Teresa; Quesada Molina, Juan Felipe

    2016-01-01

    El objetivo de la presente investigación fue determinar en qué medida se puede reducir el consumo de energía en el sector residencial de la ciudad de Cuenca, manteniendo óptimas condiciones de confort. El estudio se centra en la definición de indicadores de eficiencia energética para la vivienda, mediante la determinación de la demanda de energía y la definición de los factores de mayor consumo, usando un enfoque cualitativo y cuantitativo. Se realizaron encuestas en 280 viviendas del sector ...

  10. Asturias en el sistema energético: del nacionalismo a la globalización

    OpenAIRE

    Maurín Álvarez, Manuel

    2011-01-01

    Con una demanda energética regional estancada y al mismo tiempo en que se clausuran las últimas explotaciones mineras, principales proveedoras de materias primas energéticas autóctonas, Asturias se aventura a la construcción de infraestructuras de generación y transporte que permitirían duplicar en los próximos años una producción eléctrica que ya es excedentaria. La región se convierte así en una especie de «vientre de alquiler» energético, especializada en generar, con materias primas impor...

  11. Peculiarities of Vibration Characteristics of Amorphous Ices

    Science.gov (United States)

    Gets, Kirill V.; Subbotin, Oleg S.; Belosludov, Vladimir R.

    2012-03-01

    Dynamic properties of low (LDA), high (HDA) and very high (VHDA) density amorphous ices were investigated within the approach based on Lattice Dynamics simulations. In this approach, we assume that the short-range molecular order mainly determines the dynamic and thermodynamic properties of amorphous ices. Simulation cell of 512 water molecules with periodical boundary conditions and disordering allows us to study dynamical properties and dispersion curves in the Brillouin zone of pseudo-crystal. Existence of collective phenomena in amorphous ices which is usual for crystals but anomalous for disordered phase was confirmed in our simulations. Molecule amplitudes of delocalized (collective) as well as localized vibrations have been considered.

  12. Vibrational spectroscopy of proteins

    International Nuclear Information System (INIS)

    Schwaighofer, A.

    2013-01-01

    Two important steps for the development of a biosensor are the immobilization of the biological component (e.g. protein) on a surface and the enhancement of the signal to improve the sensitivity of detection. To address these subjects, the present work describes Fourier transform infrared (FTIR) investigations of several proteins bound to the surface of an attenuated total reflection (ATR) crystal. Furthermore, new nanostructured surfaces for signal enhancement were developed for use in FTIR microscopy. The mitochondrial redox-protein cytochrome c oxidase (CcO) was incorporated into a protein-tethered bilayer lipid membrane (ptBLM) on an ATR crystal featuring a roughened two-layer gold surface for signal enhancement. Electrochemical excitation by periodic potential pulses at different modulation frequencies was followed by time-resolved FTIR spectroscopy. Phase sensitive detection was used for deconvolution of the IR spectra into vibrational components. A model based on protonation-dependent chemical reaction kinetics could be fitted to the time evolution of IR bands attributed to several different redox centers of the CcO. Further investigations involved the odorant binding protein 14 (OBP14) of the honey bee (Apis mellifera), which was studied using ATR-FTIR spectroscopy and circular dichroism. OBP14 was found to be thermally stable up to 45 °C, thus permitting the potential application of this protein for the fabrication of biosensors. Thermal denaturation measurements showed that odorant binding increases the thermal stability of the OBP-odorant complex. In another project, plasmonic nanostructures were fabricated that enhance the absorbance in FTIR microscopy measurements. The nanostructures are composed of an array of round-shaped insulator and gold discs on top of a continuous gold layer. Enhancement factors of up to ⁓125 could be observed with self-assembled monolayers of dodecanethiol molecules immobilized on the gold surface (author) [de

  13. Vibrational motion in a symmetric, double minimum potential

    DEFF Research Database (Denmark)

    Spanget-Larsen, Jens

    2015-01-01

    Molecular vibrational motion in a symmetric, double minimum potential is treated by means of a quartic model potential, by reference to the tables published by Jaan Laane and the results of harmonic analyses for the stationary points. The inversion vibration of ammonia is treated in detail. - Not...... on the harmonic approximation for polyatomic molecules are appended. - Presented at a NORFA Workshop in Hirtshals, Denmark, August 1997....

  14. Balance de energía en cultivos hortícolas a campo en Rosario (Santa Fe, Argentina

    Directory of Open Access Journals (Sweden)

    J. Denoia

    2010-01-01

    Full Text Available Se analizó la gestión de la energía en cultivos de papa, tomate y lechuga en un área próxima a la ciudad de Rosario (Argentina. Se consideraron todos los ingresos de materia al sistema y su producción transformándolos en energía al multiplicar las cantidades de insumos por sus contenidos energéticos. Se analizó tanto la energía directa como la indirecta. Se estudió la gestión energética dentro de los límites físicos del sistema. Los indicadores empleados fueron: eficiencia energética (EfE y productividad energética (PE. Los balances energéticos de papa y tomate fueron negativos, mientras que en lechuga, la energía producida fue menor que la ingresada. La mayor eficiencia energética se registró en tomate (3,54, seguida por papa (2,69; la menor fue en lechuga (0,25. La energía ingresada en tomate resultó la más eficiente (88,6 kgMS/100 Mj, seguida por la de papa (16 kgMS/100 Mj y la de lechuga (10,8 kgMS/100 Mj.

  15. Nanostructure sensor of presence and concentration of a target molecule

    Science.gov (United States)

    Schipper, John F. (Inventor)

    2009-01-01

    Method and system (i) to determine when a selected target molecule is present or absent in a fluid, (2) to estimate concentration of the target molecule in the fluid and (3) estimate possible presence of a second (different) target molecule in the fluid, by analyzing differences in resonant frequencies of vibration of a thin beam suspended in the fluid, after the fluid has moved across the beam.

  16. Single Molecule Raman Detection of Enkephalin on Silver Colloidal Particles

    DEFF Research Database (Denmark)

    Kneipp, Katrin; Kneipp, Holger; Abdali, Salim

    2004-01-01

    the Raman signal the enkephalin molecules have been attached to silver colloidal cluster structures. The experiments demonstrate that the SERS signal of the strongly enhanced ring breathing vibration of phenylalanine at 1000 cm-1 can be used as “intrinsic marker” for detecting a single enkephalin molecule...... and for monitoring its diffusion on the surface of the silver colloidal cluster without using a specific label molecule....

  17. Structure, vibrations, and hydrogen bond parameters of dibenzotetraaza[14]annulene

    Science.gov (United States)

    Gawinkowski, S.; Eilmes, J.; Waluk, J.

    2010-07-01

    Geometry and vibrational structure of dibenzo[ b, i][1,4,8,11]tetraaza[14]annulene (TAA) have been studied using infrared and Raman spectroscopy combined with quantum-chemical calculations. The assignments were proposed for 106 out of the total of 108 TAA vibrations, based on comparison of the theoretical predictions with the experimental data obtained for the parent molecule and its isotopomer in which the NH protons were replaced by deuterons. Reassignments were suggesteded for the NH stretching and out-of-plane vibrations. The values of the parameters of the intramolecular NH⋯N hydrogen bonds were analysed in comparison with the corresponding data for porphyrin and porphycene, molecules with the same structural motif, a cavity composed of four nitrogen atoms and two inner protons. Both experiment and calculations suggest that the molecule of TAA is not planar and is present in a trans tautomeric form, with the protons located on the opposite nitrogen atoms.

  18. Single-Molecule Electronics with Cross- Conjugated Molecules: Quantum Interference, IETS and Non-Equilibrium "Temperatures"

    DEFF Research Database (Denmark)

    Jørgensen, Jacob Lykkebo

    Abstract The idea of using single-molecules as components in electronic devices is fas- cinating. For this idea to come into fruition, a number of technical and theo- retical challenges must be overcome. In this PhD thesis, the electron-phonon interaction is studied for a special class of molecules......, which is characterised by destructive quantum interference. The molecules are cross-conjugated, which means that the two parts of the molecules are conjugated to a third part, but not to each other. This gives rise to an anti-resonance in the trans- mission. In the low bias and low temperature regime......-conjugated molecules. We nd that the vibrational modes that would be expected to dominate, following the propensity, rules are very weak. Instead, other modes are found to be the dominant ones. We study this phenomenon for a number of cross-conjugated molecules, and link these ndings to the anti...

  19. America Saves! Energizing Main Street's Small Businesses

    Energy Technology Data Exchange (ETDEWEB)

    Lindberg, James [National Trust for Historic Preservation, Washington, DC (United States)

    2016-09-30

    The America Saves! Energizing Main Street Small Businesses project engaged the 1,200-member National Main Street Center (NMSC) network of downtown organizations and other local, regional, and national partners to test a methodology for sharing customized energy efficiency information with owners of commercial buildings smaller than 50,000 square feet. Led by the National Trust for Historic Preservation’s Preservation Green Lab, the project marshalled local staff and volunteers to gather voluntarily-disclosed energy use information from participating businesses. This information was analyzed using a remote auditing tool (validated by the National Renewable Energy Lab) to assess energy savings opportunities and design retrofit strategies targeting seven building types (food service and sales, attached mixed-use, strip mall, retail, office, lodging, and schools). The original project design contemplated extensive leveraging of the Green Button protocol for sharing annualized utility data at a district scale. Due the lack of adoption of Green Button, the project partners developed customized approaches to data collection in each of twelve pilot communities. The project team encountered considerable challenges in gathering standardized annual utility data from local partners. After overcoming these issues, the data was uploaded to a data storehouse. Over 450 properties were benchmarked and the remote auditing tool was tested using full building profiles and utility records for more than 100 commercial properties in three of the pilot communities. The audit tool demonstrated potential for quickly capturing, analyzing, and communicating energy efficiency opportunities in small commercial buildings. However, the project team found that the unique physical characteristics and use patterns (partial vacancy, periodic intensive uses) of small commercial buildings required more trouble-shooting and data correction than was anticipated. In addition, the project revealed that

  20. Mechanical vibration and shock analysis, sinusoidal vibration

    CERN Document Server

    Lalanne, Christian

    2014-01-01

    Everything engineers need to know about mechanical vibration and shock...in one authoritative reference work! This fully updated and revised 3rd edition addresses the entire field of mechanical vibration and shock as one of the most important types of load and stress applied to structures, machines and components in the real world. Examples include everything from the regular and predictable loads applied to turbines, motors or helicopters by the spinning of their constituent parts to the ability of buildings to withstand damage from wind loads or explosions, and the need for cars to m

  1. Hydroelastic Vibrations of Ships

    DEFF Research Database (Denmark)

    Jensen, Jørgen Juncher; Folsø, Rasmus

    2002-01-01

    A formula for the necessary hull girder bending stiffness required to avoid serious springing vibrations is derived. The expression takes into account the zero crossing period of the waves, the ship speed and main dimensions. For whipping vibrations the probability of exceedance for the combined...

  2. Surface vibrational spectroscopy

    International Nuclear Information System (INIS)

    Erskine, J.L.

    1984-01-01

    A brief review of recent studies which combine measurements of surface vibrational energies with lattice dynamical calculations is presented. These results suggest that surface vibrational spectroscopy offers interesting prospects for use as a molecular-level probe of surface geometry, adsorbate bond distances and molecular orientations

  3. Gearbox vibration diagnostic analyzer

    Science.gov (United States)

    1992-01-01

    This report describes the Gearbox Vibration Diagnostic Analyzer installed in the NASA Lewis Research Center's 500 HP Helicopter Transmission Test Stand to monitor gearbox testing. The vibration of the gearbox is analyzed using diagnostic algorithms to calculate a parameter indicating damaged components.

  4. Two-dimensional vibrational-electronic spectroscopy

    Science.gov (United States)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira

    2015-10-01

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (νCN) and either a ligand-to-metal charge transfer transition ([FeIII(CN)6]3- dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN)5FeIICNRuIII(NH3)5]- dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific νCN modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a wide range of complex molecular, material, and biological systems.

  5. Two-dimensional vibrational-electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Courtney, Trevor L.; Fox, Zachary W.; Slenkamp, Karla M.; Khalil, Munira, E-mail: mkhalil@uw.edu [Department of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195 (United States)

    2015-10-21

    Two-dimensional vibrational-electronic (2D VE) spectroscopy is a femtosecond Fourier transform (FT) third-order nonlinear technique that creates a link between existing 2D FT spectroscopies in the vibrational and electronic regions of the spectrum. 2D VE spectroscopy enables a direct measurement of infrared (IR) and electronic dipole moment cross terms by utilizing mid-IR pump and optical probe fields that are resonant with vibrational and electronic transitions, respectively, in a sample of interest. We detail this newly developed 2D VE spectroscopy experiment and outline the information contained in a 2D VE spectrum. We then use this technique and its single-pump counterpart (1D VE) to probe the vibrational-electronic couplings between high frequency cyanide stretching vibrations (ν{sub CN}) and either a ligand-to-metal charge transfer transition ([Fe{sup III}(CN){sub 6}]{sup 3−} dissolved in formamide) or a metal-to-metal charge transfer (MMCT) transition ([(CN){sub 5}Fe{sup II}CNRu{sup III}(NH{sub 3}){sub 5}]{sup −} dissolved in formamide). The 2D VE spectra of both molecules reveal peaks resulting from coupled high- and low-frequency vibrational modes to the charge transfer transition. The time-evolving amplitudes and positions of the peaks in the 2D VE spectra report on coherent and incoherent vibrational energy transfer dynamics among the coupled vibrational modes and the charge transfer transition. The selectivity of 2D VE spectroscopy to vibronic processes is evidenced from the selective coupling of specific ν{sub CN} modes to the MMCT transition in the mixed valence complex. The lineshapes in 2D VE spectra report on the correlation of the frequency fluctuations between the coupled vibrational and electronic frequencies in the mixed valence complex which has a time scale of 1 ps. The details and results of this study confirm the versatility of 2D VE spectroscopy and its applicability to probe how vibrations modulate charge and energy transfer in a

  6. Handbook Of Noise And Vibration

    International Nuclear Information System (INIS)

    1995-12-01

    This book is about noise and vibration. The first chapter has explanations of noise such as basic of sound, influence of noise, assessment of noise, measurement of prevention of noise and technology, case of noise measurement and soundproof. The second chapter describes vibration with outline, theory of vibration, interpretation of vibration, measurement for reduction of vibration, case of design of protection against vibration. It deals with related regulation and method of measurement.

  7. Vibration insensitive interferometry

    Science.gov (United States)

    Millerd, James; Brock, Neal; Hayes, John; Kimbrough, Brad; North-Morris, Michael; Wyant, James C.

    2017-11-01

    The largest limitation of phase-shifting interferometry for optical testing is the sensitivity to the environment, both vibration and air turbulence. An interferometer using temporal phase-shifting is very sensitive to vibration because the various phase shifted frames of interferometric data are taken at different times and vibration causes the phase shifts between the data frames to be different from what is desired. Vibration effects can be reduced by taking all the phase shifted frames simultaneously and turbulence effects can be reduced by averaging many measurements. There are several techniques for simultaneously obtaining several phase-shifted interferograms and this paper will discuss two such techniques: 1) Simultaneous phase-shifting interferometry on a single detector array (PhaseCam) and 2) Micropolarizer phase-shifting array. The application of these techniques for the testing of large optical components, measurement of vibrational modes, the phasing of segmented optical components, and the measurement of deformations of large diffuse structures is described.

  8. Vibrations of rotating machinery

    CERN Document Server

    Matsushita, Osami; Kanki, Hiroshi; Kobayashi, Masao; Keogh, Patrick

    2017-01-01

    This book opens with an explanation of the vibrations of a single degree-of-freedom (dof) system for all beginners. Subsequently, vibration analysis of multi-dof systems is explained by modal analysis. Mode synthesis modeling is then introduced for system reduction, which aids understanding in a simplified manner of how complicated rotors behave. Rotor balancing techniques are offered for rigid and flexible rotors through several examples. Consideration of gyroscopic influences on the rotordynamics is then provided and vibration evaluation of a rotor-bearing system is emphasized in terms of forward and backward whirl rotor motions through eigenvalue (natural frequency and damping ratio) analysis. In addition to these rotordynamics concerning rotating shaft vibration measured in a stationary reference frame, blade vibrations are analyzed with Coriolis forces expressed in a rotating reference frame. Other phenomena that may be assessed in stationary and rotating reference frames include stability characteristic...

  9. Multiphoton dissociation of polyatomic molecules

    International Nuclear Information System (INIS)

    Schulz, P.A.

    1979-10-01

    The dynamics of infrared multiphoton excitation and dissociation of SF 6 was investigated under collision free conditions by a crossed laser-molecular beam method. In order to understand the excitation mechanism and to elucidate the requirements of laser intensity and energy fluence, a series of experiments were carried out to measure the dissociation yield dependences on energy fluence, vibrational temperature of SF 6 , the pulse duration of the CO 2 laser and the frequency in both one and two laser experiments. Translational energy distributions of the SF 5 dissociation product measured by time of flight and angular distributions and the dissociation lifetime of excited SF 6 as inferred from the observation of secondary dissociation of SF 5 into SF 4 and F during the laser pulse suggest that the dynamics of dissociation of excited molecules is dominated by complete energy randomization and rapid intramolecular energy transfer on a nanosecond timescale, and can be adequately described by RRKM theory. An improved phenomenological model including the initial intensity dependent excitation, a rate equation describing the absorption and stimulated emission of single photons, and the unimolecular dissociation of excited molecules is constructed based on available experimental results. The model shows that the energy fluence of the laser determines the excitation of molecules in the quasi-continuum and the excess energy with which molecules dissociate after the laser pulse. The role played by the laser intensity in multiphoton dissociation is more significant than just that of overcoming the intensity dependent absorption in the lowest levels. 63 references

  10. Kinetic Simulations of Plasma Energization and Particle Acceleration in Interacting Magnetic Flux Ropes

    Science.gov (United States)

    Du, S.; Guo, F.; Zank, G. P.; Li, X.; Stanier, A.

    2017-12-01

    The interaction between magnetic flux ropes has been suggested as a process that leads to efficient plasma energization and particle acceleration (e.g., Drake et al. 2013; Zank et al. 2014). However, the underlying plasma dynamics and acceleration mechanisms are subject to examination of numerical simulations. As a first step of this effort, we carry out 2D fully kinetic simulations using the VPIC code to study the plasma energization and particle acceleration during coalescence of two magnetic flux ropes. Our analysis shows that the reconnection electric field and compression effect are important in plasma energization. The results may help understand the energization process associated with magnetic flux ropes frequently observed in the solar wind near the heliospheric current sheet.

  11. Situación energética de los hidrocarburos en el Perú

    OpenAIRE

    Rojas Lazo, Oswaldo; Rojas Rojas, Jorge; Salas Bacalla, Julio

    2014-01-01

    La tasa de crecimiento anual del consumo de energía en el mundo se incrementa a razón de 2 a 3%, teniendo a los hidrocarburos y el carbón como sus principales componentes. En el Perú las reservas probadas de energía son: gas (Camisea) con el 43% de la energía comercial, la hidroenergía 23,1%, los líquidos de gas natural con el 14,7% y otros con el 19.2%. La balanza comercial energética en el Perú es negativa, la producción de petróleo en los últimos años está descendiendo mientras que la prod...

  12. Study on infrared multiphoton excitation of the linear triatomic molecule by the Lie-algebra approach

    International Nuclear Information System (INIS)

    Feng, H.; Zheng, Y.; Ding, S.

    2007-01-01

    Infrared multiphoton vibrational excitation of the linear triatomic molecule has been studied using the quadratic anharmonic Lie-algebra model, unitary transformations, and Magnus approximation. An explicit Lie-algebra expression for the vibrational transition probability is obtained by using a Lie-algebra approach. This explicit Lie-algebra expressions for time-evolution operator and vibrational transition probabilities make the computation clearer and easier. The infrared multiphoton vibrational excitation of the DCN linear tri-atomic molecule is discussed as an example

  13. Development and energization of IOT based RF amplifier

    International Nuclear Information System (INIS)

    Mandal, A.; Som, S.; Raj, P.R.; Manna, S.K.; Ghosh, S.; Seth, S.; Thakurta, S.; Thakur, S.K.; Saha, S.; Panda, U.S.

    2013-01-01

    A 704 MHz IOT based CW RF amplifier has been developed in VECC. It can also be used with proper tuning to power cavity modules operating at 650 MHz in high energy high intensity proton linear accelerator proposed to be built for ADSS/SNS programme in India and Project-X at Fermilab, USA. This IOT based amplifier provides up to 60 kW continuous wave RF power at 700 MHz. It required various power supplies, LCW cooling and forced air cooling for its operation. The auxiliary power supplies like Grid, Filament and Ion-pump, are floated and mounted on an isolated frame, i.e., HV deck. The mains inputs are electrically isolated by means of isolation transformer. Also, a Programmable Logic Controller (PLC) based interlocks along with high voltage collector power supply has been designed and developed for the safe operation of the RF amplifier. This paper discusses about various developments and energization of the IOT based RF amplifier with high power dummy load. (author)

  14. Re-energizing enquiry among our young professionals

    Science.gov (United States)

    Roychoudhuri, ChandraSekhar

    2017-08-01

    Children are born with enquiring mindset. They keep on asking questions to explore, understand and take part in their environment. However, modern educational systems discourage persistent enquiring questions. Most students, graduating from college, can use their enquiring faculties only to solve problems at hand. They accept the theories taught as the final models for the laws of nature. They safely assume that no further deeper enquiry is needed. This is a disturbing collective tendency counter to our continuously evolving nature. We should also consciously train our minds to evolve continuously by persistently asking enquiring questions. Therefore, we suggest that we take pro-active steps to re-energize the enquiring mindset among our young professionals by organizing enquiry forums for students from all international Student Chapters during most of our optical society meetings. Panels of volunteer senior scientists should encourage deep enquiring questions from the students. In this paper, as examples, I will present a set of enquiring questions in the field of optics that we have been underscoring to students. This is one of the three papers by this author for this conference, ETOP 100-43. Since scientific content-wise they complement each other, the readers should consult the others. They are: ETP100-36, "Consequences of repeated discovery and benign neglect of non-interaction of waves" and ETP100-83, and "Demonstration and implications when 50% beam combiners can behave as 0 or 100% reflector/transmitter inside some interferometers."

  15. Energization of helium ions by proton-induced hydromagnetic waves

    International Nuclear Information System (INIS)

    Gendrin, R.; Roux, A.

    1980-01-01

    We consider the diffusion of He + ions under the influence of ion cyclotron waves generated in a plasma consisting of three different ion populations: a thermal isotropic population containing both H + and He + ions and an energetic H + population, with a positive anisotropy A=T/sub perpendicular//T/sub parallel/-1. We compute, in the velocity space upsilon/sub parallel/, upsilon/sub perpendicular/, the diffusion curves that He + ions will follow in the presence of ion cyclotron waves propagating in such a medium. We show that for small concentrations of the He + ions, of the order of 1 to approx.10%, these ions can be energized by such a process up to and above suprathermal energies (E> or approx. =20 eV). On some occasions the He + ions may even reach energies of the order of the Alfven energy of the cold plasma population: E/sub a/approx. =m/sub p/V/sub a/ 2 approx. =5 keV. Characteristic diffusion times, in pitch angle and energy, for both ion species, are evaluated. They are of the order of 2 to 20 min. These theoretical results are discussed in the frame of recent observations by Geos experimenters showing the close association that exists between the occurrence of ion cyclotron ULF waves and the presence of thermal or supra-thermal He + ions in the equatorial region of the magnetosphere

  16. Dissinfection of municipal sludge and wastewater by energized electrons

    International Nuclear Information System (INIS)

    Trump, J.G.; Wright, K.A.; Sinskey, A.J.; Shah, D.N.; Fernald, R.

    1979-01-01

    Laboratory studies at M.I.T. and high flow rate studies at the M.D.C. Deer Island Wastewater Treatment Plant in Boston have shown the practicality and cost effectiveness of disinfecting liquid municipal sludges by injecting energized electrons. A dosage of 400 Kilorads (4 Kilograys) reduces gram-negative bacteria, including coliforms, fecal coliforms, salmonellae and shigellae, in primary raw or anaerobically digested sludges to undetectable levels. Enteric viruses are reduced by one to two orders of magnitude. This treatment also destroys parasite eggs or renders them non-infectious. Model system studies indicate that trace toxic compounds such as PCBs in water are degraded. The estimated cost of sludge disinfection by electron treatment is about $0.80 per liquid tonne for modular systems of 650 liquid tonnes per day capacity. About 6 Kilowatt-hours of input electric power per tonne is required. The temperature rise of the disinfected watery sludge is about 2 0 C. Electron disinfection combined with subsurface soil injection offers an environmentally attractive, energy-efficient, and economic two -step process for land disposal of municipal sludges with water conservation and soil improvement benefits. Combined with widely-distributed ocean feeding, electron disinfection of the municipal sludge of coastal communities offers a safe marine nutrient for increasing fish population in treated ocean areas. The electron disinfection of effluent wastewater, in lieu of chlorination, is a future application which avoids the production of potentially toxic chlorinated hydrocarbons. (Author) [pt

  17. Calcium transport in vesicles energized by cytochrome oxidase

    Energy Technology Data Exchange (ETDEWEB)

    Rosier, Randy N. [Univ. of Rochester, NY (United States)

    1979-01-01

    Experiments on the reconstitution of cytochrome oxidase into phospholipid vesicles were carried out using techniques of selectivity energizing the suspensions with ascorbate and cytochrome c or ascorbate, PMS, and internally trapped cytochrome c. It was found that the K+ selective ionophore valinomycin stimulated the rate of respiration of cytochrome oxidase vesicles regardless of the direction of the K+ flux across the vesicle membranes. The stimulation occurred in the presence of protonophoric uncouplers and in the complete absence of potassium or in detergent-lysed suspensions. Gramicidin had similar effects and it was determined that the ionophores acted by specific interaction with cytochrome oxidase rather than by the previously assumed collapse of membrane potentials. When hydrophobic proteins and appropriate coupling factors were incorporated into the cytochrome oxidase, vesicles phosphorylation of ADP could be coupled to the oxidation reaction of cytochrome oxidase. Relatively low P:O, representing poor coupling of the system, were problematical and precluded measurements of protonmotive force. However the system was used to study ion translocation.

  18. Cálculo del balance de energía para higuerilla (Ricinus communis L. desde las etapas de producción en campo hasta el valor energético de cada componente de la planta

    Directory of Open Access Journals (Sweden)

    Hipólito Ortíz-Laurel

    2017-01-01

    Full Text Available Introducción : Pruebas de balance de energía permiten redirigir los insumos desde las etapas de producción de un cultivo, e igualmente, precesar la cantidad de energía utilizada para cada proceso y así, verificar la eficiencia al transformar la energía contenida en el cultivo cuando debe cumplir con una función deseada. Método : la planta de higuerilla (Ricinus communis L. con propósitos de cultivo energético fue sembrada en campo y sometida a procesos de mantenimiento de l cultivo y en la cosecha, la planta completa fue colectada para análisis energético, donde cada una de sus partes inclu i das las semillas fueron evaluadas en función de su contenido de energía. Así, para determinar el balance de energía; los valores de la energía biológica de la planta fueron comparados con la energía aplicada en cada uno de los procesos técnicos y físicos para la producción del cult i vo y en su procesamiento . Resultados : La energía aplicada para producir el cultivo r esulta un 28% superior a la energía a obtener de la planta. Asimismo, la biomasa de la planta completa de higuerilla, sin contar las semillas genera el doble de energía comparado con el aceite de las semillas, por lo que, conviene utilizar toda la planta e n términos de energía . Conclusión : Es recomendable utilizar el aceite de las seillas como biomaterial, ya que el b a lance es positivo en un 15%.

  19. Vibrationally Excited Carbon Monoxide Produced via a Chemical Reaction Between Carbon Vapor and Oxygen

    Science.gov (United States)

    Jans, Elijah R.; Eckert, Zakari; Frederickson, Kraig; Rich, Bill; Adamovich, Igor V.

    2017-06-01

    Measurements of the vibrational distribution function of carbon monoxide produced via a reaction between carbon vapor and molecular oxygen has shown a total population inversion on vibrational levels 4-7. Carbon vapor, produced using an arc discharge to sublimate graphite, is mixed with an argon oxygen flow. The excited carbon monoxide is vibrationally populated up to level v=14, at low temperatures, T=400-450 K, in a collision-dominated environment, 15-20 Torr, with total population inversions between v=4-7. The average vibrational energy per CO molecule formed by the reaction is 0.6-1.2 eV/molecule, which corresponds to 10-20% of the reaction enthalpy. Kinetic modeling of the flow reactor, including state specific vibrational processes, was performed to infer the vibrational distribution of the products of the reaction. The results show viability of developing of a new chemical CO laser from the reaction of carbon vapor and oxygen.

  20. Silicon micromachined vibrating gyroscopes

    Science.gov (United States)

    Voss, Ralf

    1997-09-01

    This work gives an overview of silicon micromachined vibrating gyroscopes. Market perspectives and fields of application are pointed out. The advantage of using silicon micromachining is discussed and estimations of the desired performance, especially for automobiles are given. The general principle of vibrating gyroscopes is explained. Vibrating silicon gyroscopes can be divided into seven classes. for each class the characteristic principle is presented and examples are given. Finally a specific sensor, based on a tuning fork for automotive applications with a sensitivity of 250(mu) V/degrees is described in detail.

  1. System Detects Vibrational Instabilities

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1990-01-01

    Sustained vibrations at two critical frequencies trigger diagnostic response or shutdown. Vibration-analyzing electronic system detects instabilities of combustion in rocket engine. Controls pulse-mode firing of engine and identifies vibrations above threshold amplitude at 5.9 and/or 12kHz. Adapted to other detection and/or control schemes involving simultaneous real-time detection of signals above or below preset amplitudes at two or more specified frequencies. Potential applications include rotating machinery and encoders and decoders in security systems.

  2. Exotic helium molecules; Molecules exotiques d'helium

    Energy Technology Data Exchange (ETDEWEB)

    Portier, M

    2007-12-15

    We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}P{sub 0}) molecule, or a {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 {+-} 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime {tau} = (1.4 {+-} 0.3) {mu}s is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

  3. Exotic helium molecules; Molecules exotiques d'helium

    Energy Technology Data Exchange (ETDEWEB)

    Portier, M

    2007-12-15

    We study the photo-association of an ultracold cloud of magnetically trapped helium atoms: pairs of colliding atoms interact with one or two laser fields to produce a purely long range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}P{sub 0}) molecule, or a {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) long range molecule. Light shifts in one photon photo-association spectra are measured and studied as a function of the laser polarization and intensity, and the vibrational state of the excited molecule. They result from the light-induced coupling between the excited molecule, and bound and scattering states of the interaction between two metastable atoms. Their analysis leads to the determination of the scattering length a = (7.2 {+-} 0.6) ruling collisions between spin polarized atoms. The two photon photo-association spectra show evidence of the production of polarized, long-range {sup 4}He{sub 2}(2{sup 3}S{sub 1}-2{sup 3}S{sub 1}) molecules. They are said to be exotic as they are made of two metastable atoms, each one carrying a enough energy to ionize the other. The corresponding lineshapes are calculated and decomposed in sums and products of Breit-Wigner and Fano profiles associated to one and two photon processes. The experimental spectra are fit, and an intrinsic lifetime {tau} = (1.4 {+-} 0.3) {mu}s is deduced. It is checked whether this lifetime could be limited by spin-dipole induced Penning autoionization. This interpretation requires that there is a quasi-bound state close to the dissociation threshold in the singlet interaction potential between metastable helium atoms for the theory to match the experiment. (author)

  4. Imaging quantum vibrations on an ultrashort timescale: the deuterium molecular ion

    International Nuclear Information System (INIS)

    McKenna, J; Calvert, C R; Bryan, W A; English, E M L; Wood, J; Murphy, D S; Turcu, I C E; Smith, J M; Ertel, K G; Chekhlov, O; Divall, E J; McCann, J F; Newell, W R; Williams, I D

    2007-01-01

    The vibrational wavepacket revival of a basic quantum system is demonstrated experimentally. Using few-cycle laser pulse technology, pump and probe imaging of the vibrational motion of D + 2 molecules is conducted, and together with a quantum-mechanical simulation of the excited wavepacket motion, the vibrational revival phenomenon has been characterised. The simulation shows good correlation with the temporal motion and structural features obtained from the data, relaying fundamental information on this diatomic system

  5. Vibrational spectra and normal co-ordinate analysis of 2-aminopyridine and 2-amino picoline.

    Science.gov (United States)

    Jose, Sujin P; Mohan, S

    2006-05-01

    The Fourier transform infrared (FT-IR) and Raman (FT-R) spectra of 2-aminopyridine and 2-amino picoline were recorded and the observed frequencies were assigned to various modes of vibration in terms of fundamentals by assuming Cs point group symmetry. A normal co-ordinate analysis was also carried out for the proper assignment of the vibrational frequencies using simple valence force field. A complete vibrational analysis is presented here for the molecules and the results are briefly discussed.

  6. Raman Optical Activity of Biological Molecules

    Science.gov (United States)

    Blanch, Ewan W.; Barron, Laurence D.

    Now an incisive probe of biomolecular structure, Raman optical activity (ROA) measures a small difference in Raman scattering from chiral molecules in right- and left-circularly polarized light. As ROA spectra measure vibrational optical activity, they contain highly informative band structures sensitive to the secondary and tertiary structures of proteins, nucleic acids, viruses and carbohydrates as well as the absolute configurations of small molecules. In this review we present a survey of recent studies on biomolecular structure and dynamics using ROA and also a discussion of future applications of this powerful new technique in biomedical research.

  7. Quenching vibrations by collisions in cold traps: A quantum study for ...

    Indian Academy of Sciences (India)

    Scattering theory; ion-molecule collisions vibrational quenching. 1. ... Hence, considerable attention has now turned to .... computed spatial features of the interaction potential for .... radial integration of the coupled equation was extended.

  8. Intramolecular Vibrational Energy Transfer and Bond-Selected Photochemistry in Liquids

    National Research Council Canada - National Science Library

    Crim, F

    2001-01-01

    .... In the gas phase experiments, one pulse excited the first overtone of the O-H stretching vibration in nitric acid and the second pulse probed the excited molecule by excitation to a dissociative...

  9. Apparatus for deploying and energizing submersible electric motor downhole

    International Nuclear Information System (INIS)

    Conner, S.E.; Dwiggins, J.L.; Brookbank, E.B.

    1991-01-01

    This patent describes an apparatus for deploying and energizing a submergible electric motor downhole. It comprises a cable socket assembly and a cable connecting-and-sealing chamber assembly adapted to be arranged seriatim in the path of cable means and the motor, the assemblies having first and second housings, respectively, means for connecting a lower end of the first housing to an upper end of the second housing, a lower end of the second housing being adapted for connection to the motor, the cable socket assembly having an attachment portion including means for attaching a weight-bearing cable of the cable means to the first housing via a breakaway connection, the first housing having a passage therein adapted to pass an electrical cable of the cable means to the second housing, the second housing being divided by a body therein into first and second chambers sealed from each other, the first chamber being adapted to communicate sealingly with the passage and the second chamber being adapted to communicate sealingly with the interior of the motor, a first set of electrical conductors in the first chamber and a second set of electrical conductors in the second chamber, the body having feed-through means for electrically interconnecting conductors of the first set with corresponding conductors of the second set, the conductors of the first set having electrical connector parts adapted to connect releasably with corresponding electrical connector parts of the electrical cable, and the conductors of the second set having electrical connector parts adapted to connect with corresponding electrical connector parts of the motor, each of the chambers being adapted to be filled with fluid to exclude well fluid therefrom

  10. Molecule Matters van der Waals Molecules

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Molecule Matters van der Waals Molecules - Rg•••HF Complexes are Debye Molecules! E Arunan. Feature Article Volume 15 Issue 7 July 2010 pp 667-674. Fulltext. Click here to view fulltext PDF. Permanent link:

  11. Excited states rotational effects on the behavior of excited molecules

    CERN Document Server

    Lim, Edward C

    2013-01-01

    Excited States, Volume 7 is a collection of papers that discusses the excited states of molecules. The first paper reviews the rotational involvement in intra-molecular in vibrational redistribution. This paper analyzes the vibrational Hamiltonian as to its efficacy in detecting the manifestations of intra-molecular state-mixing in time-resolved and time-averaged spectroscopic measurements. The next paper examines the temporal behavior of intra-molecular vibration-rotation energy transfer (IVRET) and the effects of IVRET on collision, reaction, and the decomposition processes. This paper also

  12. Precise Ab-initio prediction of terahertz vibrational modes in crystalline systems

    DEFF Research Database (Denmark)

    Jepsen, Peter Uhd; Clark, Stewart J.

    2007-01-01

    We use a combination of experimental THz time-domain spectroscopy and ab-initio density functional perturbative theory to accurately predict the terahertz vibrational spectrum of molecules in the crystalline phase. Our calculations show that distinct vibrational modes found in solid-state materials...

  13. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 4th edition of this textbook on linear stochastic vibration th...... theory is unchanged in comparison to the 3rd edition. Only a few errors have been corrected.......The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 4th edition of this textbook on linear stochastic vibration...

  14. Improved Laser Vibration Radar

    National Research Council Canada - National Science Library

    Hilaire, Pierre

    1998-01-01

    .... This thesis reconfigured an existing CO2 laboratory laser radar system that is capable of measuring the frequencies of vibration of a simulated target into a more compact and rugged form for field testing...

  15. NIF Ambient Vibration Measurements

    International Nuclear Information System (INIS)

    Noble, C.R.; Hoehler, M.S.; S.C. Sommer

    1999-01-01

    LLNL has an ongoing research and development project that includes developing data acquisition systems with remote wireless communication for monitoring the vibrations of large civil engineering structures. In order to establish the capability of performing remote sensing over an extended period of time, the researchers needed to apply this technology to a real structure. The construction of the National Ignition Facility provided an opportunity to test the data acquisition system on a large structure to monitor whether the facility is remaining within the strict ambient vibration guidelines. This document will briefly discuss the NIF ambient vibration requirements and summarize the vibration measurements performed during the Spring and Summer of 1999. In addition, a brief description of the sensors and the data acquisition systems will be provided in Appendix B

  16. A vibration sieve

    Energy Technology Data Exchange (ETDEWEB)

    Alekhin, S.A.; Denisenko, V.V.; Dzhalalov, M.G.; Kirichek, F.P.; Pitatel, Yu.A.; Prokopov, L.I.; Tikhonov, Yu.P.

    1982-01-01

    A vibration sieve is proposed which includes a vibration drive, a body and a screen installed on shock absorbers, a device for washing out the screen, and a subassembly for loading the material. To increase the operational reliability and effectiveness of the vibration sieve by improving the cleaning of the screen, the loading subassembly is equipped with a baffle with a lever which is hinged to it. The device for washing out the screen is made in the form of an electromagnet with a connecting rod, a switch and an eccentric, a friction ratchet mechanism and sprinkling systems. Here, the latter are interconnected, using a connecting rod, while the sprinkling system is installed on rollers under the screen. The electromagnetic switch is installed under the lever. The body is made with grooves for installing the sprinkling system. The vibration sieve is equipped with a switch which interacts with the connecting rod. The friction ratchet mechanism is equipped with a lug.

  17. La Seguridad Energética y la Estrategia Global de Seguridad de la Unión Europea

    Directory of Open Access Journals (Sweden)

    Ruben Herrero

    2016-10-01

    Full Text Available El presente artículo plantea una definición ampliada del concepto de seguridad energética, yendo más allá del concepto clásico establecido por la Agencia Internacional de la Energía, incorporando cuestiones relativas a la eficiencia energética, la aceptabilidad del modelo energético y los retos que impone el cambio climático, pero sin perder de perspectiva las exigencias y las dinámicas competitivas económicas globales. Sobre la base de este concepto ampliado, se examina la evolución de la seguridad energética en el marco de la Unión Europea, con una atención particular a cómo se concibe la seguridad energética en la Estrategia Global de Seguridad de 2016.

  18. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

    This book offers an integrated introduction to the topic of stability and vibration. Strikingly, it describes stability as a function of boundary conditions and eigenfrequency as a function of both boundary conditions and column force. Based on a post graduate course held by the author at the Uni...... and their derivation, thus stimulating them to write interactive and dynamic programs to analyze instability and vibrational modes....

  19. Costo energético de muros y techos utilizados en la zona sur de Tamaulipas

    Directory of Open Access Journals (Sweden)

    Mireya Alicia Rosas Lusett

    2015-01-01

    Full Text Available El presente trabajo muestra los procedimientos y resultados obtenidos del análisis de la energía trasmitida en techos y muros de las viviendas seleccionadas de la zona sur del estado de Tamaulipas, una de las cinco áreas establecidas dentro del proyecto “Desarrollo y validación de una metodología para estimar los impactos en el ahorro de energía por el uso de sistemas pasivo-constructivos en la edificación para diferentes climas de México”. Este proyecto fue financiado por la Convocatoria S0019-2009-01 del Fondo Sectorial de Sustentabilidad Energética SENER-CONACYT con registro Nº 118665, cuyo objetivo en su tercera etapa de ejecución, consistió en hacer uso de la herramienta Ener-Habitat, la cual fue desarrollada durante la segunda fase del proyecto. Con dicho programa de cálculo se determinaron los gastos de energía, comparativa de cuatro sistemas constructivos para muros y tres sistemas constructivos para losas utilizadas en la zona sur de Tamaulipas. Con la información obtenida y mediante el uso de la metodología desarrollada para estimar los impactos en el ahorro de energía, se evaluó el costo energético de cada uno de los sistemas constructivos. Con los resultados obtenidos se pudo determinar cuál era el muro y techo de menor gasto de energía para la zona de estudio. Adicionalmente se realizó un estudio de la influencia de la absortancia solar de la superficie exterior de los muros, cuyos resultados darán la pauta para diseñar una vivienda que pretende sea adecuada y cómoda al clima cálido húmedo que prevalece en el área.

  20. Electric moments in molecule interferometry

    International Nuclear Information System (INIS)

    Eibenberger, Sandra; Gerlich, Stefan; Arndt, Markus; Tuexen, Jens; Mayor, Marcel

    2011-01-01

    We investigate the influence of different electric moments on the shift and dephasing of molecules in a matter wave interferometer. Firstly, we provide a quantitative comparison of two molecules that are non-polar yet polarizable in their thermal ground state and that differ in their stiffness and response to thermal excitations. While C 25 H 20 is rather rigid, its larger derivative C 49 H 16 F 52 is additionally equipped with floppy side chains and vibrationally activated dipole moment variations. Secondly, we elucidate the role of a permanent electric dipole momentby contrasting the quantum interference pattern of a (nearly) non-polar and a polar porphyrin derivative. We find that a high molecular polarizability and even sizeable dipole moment fluctuations are still well compatible with high-contrast quantum interference fringes. The presence of permanent electric dipole moments, however, can lead to a dephasing and rapid degradation of the quantum fringe pattern already at moderate electric fields. This finding is of high relevance for coherence experiments with large organic molecules, which are generally equipped with strong electric moments.

  1. Vibrational and orientational dynamics of water in aqueous hydroxide solutions.

    Science.gov (United States)

    Hunger, Johannes; Liu, Liyuan; Tielrooij, Klaas-Jan; Bonn, Mischa; Bakker, Huib

    2011-09-28

    We report the vibrational and orientational dynamics of water molecules in isotopically diluted NaOH and NaOD solutions using polarization-resolved femtosecond vibrational spectroscopy and terahertz time-domain dielectric relaxation measurements. We observe a speed-up of the vibrational relaxation of the O-D stretching vibration of HDO molecules outside the first hydration shell of OH(-) from 1.7 ± 0.2 ps for neat water to 1.0 ± 0.2 ps for a solution of 5 M NaOH in HDO:H(2)O. For the O-H vibration of HDO molecules outside the first hydration shell of OD(-), we observe a similar speed-up from 750 ± 50 fs to 600 ± 50 fs for a solution of 6 M NaOD in HDO:D(2)O. The acceleration of the decay is assigned to fluctuations in the energy levels of the HDO molecules due to charge transfer events and charge fluctuations. The reorientation dynamics of water molecules outside the first hydration shell are observed to show the same time constant of 2.5 ± 0.2 ps as in bulk liquid water, indicating that there is no long range effect of the hydroxide ion on the hydrogen-bond structure of liquid water. The terahertz dielectric relaxation experiments show that the transfer of the hydroxide ion through liquid water involves the simultaneous motion of ~7 surrounding water molecules, considerably less than previously reported for the proton. © 2011 American Institute of Physics

  2. Performance of bismuth tape current leads under vibration; Bi tepu sei denryu rido no shindo tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Suzuki, E.; Kurihara, M. [Railway Techniical Research Institute, Tokyo (Japan)

    2000-02-25

    The superconducting magnets on Maglev vehicles when running vibrate mechanically due to electromagnetic disturbance from the ground coils. Therefore, the current leads fixed on the superconducting coil, which is vibration at about 98 m/s{sup 2} (=10g), are also required to endure the vibration. We executed dynamic vibration tests for two types of current leads (straight and arc types) which had a multi-stacked configuration of Ag-sheathed Bi2223 tapes impregnated with epoxy resin in a concaved reinforcing gutter. We evaluated the straight-type lead for an operating current of 700 A after every vibration test in liquid nitrogen for one hour under the dynamic strain deformation of 50-100 {mu} on the surface of the reinforcing material covering the current lead. We could not detect degradation of the current lead by vibration through the total cycles of 3.9 x 10{sup 6} after continuous vibration tests. We also executed vibration tests for arc-type current leads which were combined with an actual energized superconducting coil for a Maglev. Large accelerations of these current leads occurred at frequencies of 308 and 375 Hz. In spite of the maximum acceleration of 600-700 m/s{sup 2} generated by actuating the excessive force on a superconducting coil for two seconds, which occurred on these current leads carrying 500 A, the superconductivity of the current leads did not shift to normal conductivity. There was no damage to either type of current lead during these vibration tests. So we confirmed the good prospect for the application of these current leads to actual Maglev superconducting magnets. (author)

  3. Determining the static electronic and vibrational energy correlations via two-dimensional electronic-vibrational spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Hui; Lewis, Nicholas H. C.; Oliver, Thomas A. A.; Fleming, Graham R., E-mail: grfleming@lbl.gov [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, Californial 94720 (United States); Kavli Energy NanoSciences Institute at Berkeley, Berkeley, California 94720 (United States)

    2015-05-07

    Changes in the electronic structure of pigments in protein environments and of polar molecules in solution inevitably induce a re-adaption of molecular nuclear structure. Both changes of electronic and vibrational energies can be probed with visible or infrared lasers, such as two-dimensional electronic spectroscopy or vibrational spectroscopy. The extent to which the two changes are correlated remains elusive. The recent demonstration of two-dimensional electronic-vibrational (2DEV) spectroscopy potentially enables a direct measurement of this correlation experimentally. However, it has hitherto been unclear how to characterize the correlation from the spectra. In this paper, we present a theoretical formalism to demonstrate the slope of the nodal line between the excited state absorption and ground state bleach peaks in the spectra as a characterization of the correlation between electronic and vibrational transition energies. We also show the dynamics of the nodal line slope is correlated to the vibrational spectral dynamics. Additionally, we demonstrate the fundamental 2DEV spectral line-shape of a monomer with newly developed response functions.

  4. Extracción de energía del agua mediante generadores piezoeléctricos

    OpenAIRE

    Rodríguez Mendoza, Iker

    2014-01-01

    El desarrollo del Proyecto consiste, por una parte, en el estudio sobre la respuesta de los materiales piezoeléctricos como generadores de energía en un entorno acuoso que está sometido a variaciones de potencial y, por otra, en el estudio técnico y económico de un equipo basado en la utilización esta fuente de energía y su comercialización en el mercado energético. Esta energía es la que se obtiene de la fuerza de arrastre del agua al desplazarse a causa del movimiento ondulatorio de las ol...

  5. Costo energético de las labores de preparación de suelo en Cuba

    OpenAIRE

    Pedro Paneque Rondón; Dailyn Soto León

    2007-01-01

    El objetivo fundamental del trabajo fue determinar el costo energético de las operaciones agrícolas mecanizadas y comparar los costos energéticos de los distintos tamaños (anchos de trabajo) de los aperos más utilizados en el país para la preparación de suelo, testando la hipótesis de que el costo energético expresado en MJ/ha es independiente del tamaño del equipo. Los resultados de la investigación permitieron llegar a las siguientes conclusiones: los mayores costos energéticos cor...

  6. Vulnerabilidad energética en la metrópoli de Buenos Aires

    Directory of Open Access Journals (Sweden)

    Silvina Carrizo

    2014-06-01

    Full Text Available Argentina declaró el uso racional y la eficacia energética una prioridad nacional, en consonancia con las recomendaciones de la Agencia Internacional de la Energía. Buenos Aires se ha comprometido con varios programas internacionales de preparación al cambio climático. Así a distintas escalas surgen iniciativas para modificar las condiciones y modalidades de aprovisionamiento y consumo energéticos, que revelan la precariedad y vulnerabilidad del sistema y los servicios. Este trabajo presenta una reflexión sobre los cambios que se dan en ese sentido, mostrando los inconvenientes del modelo energético argentino en Buenos Aires y las estrategias o medidas que tienden a revertirlos y a preparar la ciudad para situaciones críticas. En general, se trata de iniciativas que se implementan individual o parcialmente, sin que haya un plan integral promovido a escala colectiva. Las correcciones resultan marginales en el conjunto sin aliviar los problemas que se agravan por el crecimiento vertiginoso de las demandas. Entonces la continuidad del modelo energético argentino basado en hidrocarburos, para abastecer infraestructura que trabaja al límite de su capacidad y servir territorios que no se han preparado para las posibles crisis, explicaría la vulnerabilidad del sistema de abastecimiento metropolitano.

  7. Development of high electrical resistance persistent current switch for high speed energization system

    International Nuclear Information System (INIS)

    Jizo, Y.; Furuta, Y.; Nakashima, H.

    1986-01-01

    Japanese National Railways is now developing a superconducting magnetically-levitated train system. A persistent current switch is incorporated in the super-conducting magnet used in the magnetically-levitated train. In recent years, the switch has been required to have higher electrical resistance during its off-state in order to realize the high speed energization/de-energization system of the superconducting magnets. The system aims to decrease evaporation volume of liquid helium during the energization/de-energization of the magnet, by means of energizing the superconducting magnet with high current increasing/decreasing rate. Consequently, it would be possible to decrease the dependence of the on-board magnet system upon the ground cooling system. Through the development of a stable superconductive wire material and a coil structure for the persistent current switch using many small model switches which were produced in order to improve their current carrying capacities, the authors have succeeded in manufacturing the high electrical resistance persistent current switch whose electrical resistance was 5 ohms. The switch, of cylindrical shape, has a diameter of about 100mm, a length of about 100mm. These 5 ohm PCSs are now functioning in stable conditions being incorporated in the superconducting magnets of No.2 vehicle of MLU001 at the JNR's Miyazaki test track. Further, the authors are now developing the PCS of still higher resistance values, such as 50 ohms, through studies for stabilization in structural aspects of the winding and obtaining results therefrom

  8. Perspectivas del potencial energético de la biomasa en el marco global y latinoamericano

    Directory of Open Access Journals (Sweden)

    Julián Rodrigo Quintero González

    2015-06-01

    Full Text Available El calentamiento global y los cambios climáticos que éste conlleva han fomentado desde hace algunos años la exploración de otros tipos de obtención energética para disminuir el uso del combustible fósil, siendo éste último uno de los principales causantes de dicho problema ambiental. El presente artículo expone algunas investigaciones recientes sobre la bioenergía u obtención de energía a partir de biomasa, considerada como energía limpia. Se abarcan temáticas como la bioenergía y sus posibilidades desde el punto de vista energético, teniendo en cuenta las expectativas de producción según su potencial o productividad energética, además del aporte que este tipo de tecnología hace a la disminución de la huella ecológica.

  9. The Roles of Fluid Compression and Shear in Electron Energization during Magnetic Reconnection

    Science.gov (United States)

    Li, Xiaocan; Guo, Fan; Li, Hui; Birn, Joachim

    2018-03-01

    Particle acceleration in space and astrophysical reconnection sites is an important unsolved problem in studies of magnetic reconnection. Earlier kinetic simulations have identified several acceleration mechanisms that are associated with particle drift motions. Here, we show that, for sufficiently large systems, the energization processes due to particle drift motions can be described as fluid compression and shear, and that the shear energization is proportional to the pressure anisotropy of energetic particles. By analyzing results from fully kinetic simulations, we show that the compression energization dominates the acceleration of high-energy particles in reconnection with a weak guide field, and the compression and shear effects are comparable when the guide field is 50% of the reconnecting component. Spatial distributions of those energization effects reveal that reconnection exhausts, contracting islands, and island-merging regions are the three most important regions for compression and shear acceleration. This study connects particle energization by particle guiding-center drift motions with that due to background fluid motions, as in the energetic particle transport theory. It provides foundations for building particle transport models for large-scale reconnection acceleration such as those in solar flares.

  10. Design of a hybrid power system based on solar cell and vibration energy harvester

    Science.gov (United States)

    Zhang, Bin; Li, Mingxue; Zhong, Shaoxuan; He, Zhichao; Zhang, Yufeng

    2018-03-01

    Power source has become a serious restriction of wireless sensor network. High efficiency, self-energized and long-life renewable source is the optimum solution for unmanned sensor network applications. However, single renewable power source can be easily affected by ambient environment, which influences stability of the system. In this work, a hybrid power system consists of a solar panel, a vibration energy harvester and a lithium battery is demonstrated. The system is able to harvest multiple types of ambient energy, which extends its applicability and feasibility. Experiments have been conducted to verify performance of the system.

  11. CO 2 laser photoacoustic spectra and vibrational modes of heroin ...

    Indian Academy of Sciences (India)

    Heroin, morphine and narcotine are very large molecules having 50, 40 and 53 atoms respectively. Moderately high resolution photoacoustic (PA) spectra have been recorded in 9.6 m and 10.6 m regions of CO2 laser. It is very difficult to assign the modes of vibrations for PA bands by comparison with conventional low ...

  12. Vibrational spectroscopy on intermolecular interactions in solutions and at interfaces

    NARCIS (Netherlands)

    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

  13. On the nature of highly vibrationally excited states of thiophosgene

    Indian Academy of Sciences (India)

    Understanding the nature of the highly excited molecu- lar eigenstates is equivalent to deciphering the mecha- nism of intramolecular vibrational energy redistribution. (IVR) occurring in the molecule.1 However, the assign- ment of eigenstates is far from simple. The existence of and interplay of several strong anharmonic ...

  14. Vibrational Analysis of (SCN)2 and the Transient (SCN)2

    DEFF Research Database (Denmark)

    Jensen, N. H.; Wilbrandt, Robert Walter; Pagsberg, Palle Bjørn

    1979-01-01

    The vibrational spectra of thiocyanogen and the transient radical anion (SCN)2− are interpreted in detail through molecular orbital and normal coordinate calculations. The results support the assignment of (SCN)2− to the anion of thiocyanogen and indicate a substantial weakening of the S–S and C......≡N bonds in going from the parent molecule to its radical anion....

  15. Laser-induced vibrational dynamics of ozone in solid argon

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Amstrup, B.; Henriksen, Niels Engholm

    1997-01-01

    We consider the vibrational dynamics, induced by an intense infrared laser pulse, in an ozone molecule with isotopic substitution, that is, (OOO)-O-16-O-16-O-18 and compare the dynamics in the gas phase and in solid ar on. not perturbed by argon on a time-scale of a few picoseconds and selective...

  16. Manipulation of molecular vibrational motions via pure rotational excitations

    DEFF Research Database (Denmark)

    Shu, Chuan-Cun; Henriksen, Niels Engholm

    2015-01-01

    The coupling between different molecular degrees of freedom plays a decisive role in many quantum phenomena, including electron transfer and energy redistribution. Here, we demonstrate a quantum-mechanical time-dependent simulation to explore how a vibrational motion in a molecule can be affected...

  17. Nonadiabatic Response Model of Laser-Induced Ultrafast π-Electron Rotations in Chiral Aromatic Molecules

    International Nuclear Information System (INIS)

    Kanno, Manabu; Kono, Hirohiko; Fujimura, Yuichi; Lin, Sheng H.

    2010-01-01

    We theoretically investigated the nonadiabatic couplings between optically induced π-electron rotations and molecular vibrations in a chiral aromatic molecule irradiated by a nonhelical, linearly polarized laser pulse. The results of wave packet dynamics simulation show that the vibrational amplitudes strongly depend on the initial rotation direction, clockwise or counterclockwise, which is controlled by the polarization direction of the incident pulse. This suggests that attosecond π-electron rotations can be observed by spectroscopic detection of femtosecond molecular vibrations.

  18. Low-energy positron interactions with atoms and molecules

    International Nuclear Information System (INIS)

    Surko, C M; Gribakin, G F; Buckman, S J

    2005-01-01

    This paper is a review of low-energy positron interactions with atoms and molecules. Processes of interest include elastic scattering, electronic and vibrational excitation, ionization, positronium formation and annihilation. An overview is presented of the currently available theoretical and experimental techniques to study these phenomena, including the use of trap-based positron beam sources to study collision processes with improved energy resolution. State-resolved measurements of electronic and vibrational excitation cross sections and measurement of annihilation rates in atoms and molecules as a function of incident positron energy are discussed. Where data are available, comparisons are made with analogous electron scattering cross sections. Resonance phenomena, common in electron scattering, appear to be less common in positron scattering. Possible exceptions include the sharp onsets of positron-impact electronic and vibrational excitation of selected molecules. Recent energy-resolved studies of positron annihilation in hydrocarbons containing more than a few carbon atoms provide direct evidence that vibrational Feshbach resonances underpin the anomalously large annihilation rates observed for many polyatomic species. We discuss open questions regarding this process in larger molecules, as well as positron annihilation in smaller molecules where the theoretical picture is less clear. (topical review)

  19. Propuesta de la certificación energética, mediante simulación dinámica, como herramienta de gestión energética ISO 50001 Versus auditoria energética en edificios.

    OpenAIRE

    Rey Hernández, Javier María; Rey Hernández, Alberto; Velasco, Eloy; San José, Julio; Rey Martinez, Francisco Javier

    2017-01-01

    Producción Científica El objetivo es el estudio de la gestión energética ISO 50001, mediante las herramientas de sistema de gestión tales como la auditoría energética y compararlo con la certificación energética mediante simulación dinámica, aplicadas a un edificio universitario estándar. La metodología empleada para alcanzar unos resultados de ahorro y eficiencia energética, aplicados a un edificio universitario, pretenden servir de modelo para poder extrapolarlos a edificios que compo...

  20. Inelastic Transport through Molecules: Comparing First-Principles Calculations to Experiments

    DEFF Research Database (Denmark)

    Paulsson, Magnus; Frederiksen, Thomas; Brandbyge, Mads

    2006-01-01

    We present calculations of the elastic and inelastic conductance through three different hydrocarbon molecules connected to gold electrodes. Our method is based on a combination of the nonequilibrium Green's function method with density functional theory. Vibrational effects in these molecular...

  1. Formation of ultracold NaRb Feshbach molecules

    International Nuclear Information System (INIS)

    Wang, Fudong; He, Xiaodong; Li, Xiaoke; Zhu, Bing; Chen, Jun; Wang, Dajun

    2015-01-01

    We report the creation of ultracold bosonic 23 Na 87 Rb Feshbach molecules via magneto-association. By ramping the magnetic field across an interspecies Feshbach resonance (FR), at least 4000 molecules can be produced out of the near degenerate ultracold mixture. Fast loss due to inelastic atom–molecule collisions is observed, which limits the pure molecule number, after residual atoms removal, to 1700. The pure molecule sample can live for 21.8(8) ms in the optical trap, long enough for future molecular spectroscopy studies toward coherently transferring to the singlet ro-vibrational ground state, where these molecules are stable against chemical reaction and have a permanent electric dipole moment of 3.3 Debye. We have also measured the Feshbach molecule’s binding energy near the FR by the oscillating magnetic field method and found these molecules have a large closed-channel fraction. (paper)

  2. Far-infrared vibrational modes of DNA components studied by terahertz time-domain spectroscopy

    International Nuclear Information System (INIS)

    Fischer, B M; Walther, M; Jepsen, P Uhd

    2002-01-01

    The far-infrared dielectric function of a wide range of organic molecules is dominated by vibrations involving a substantial fraction of the atoms forming the molecule and motion associated with intermolecular hydrogen bond vibrations. Due to their collective nature such modes are highly sensitive to the intra- and intermolecular structure and thus provide a unique fingerprint of the conformational state of the molecule and effects of its environment. We demonstrate the use of terahertz time-domain spectroscopy (THz-TDS) for recording the far-infrared (0.5-4.0 THz) dielectric function of the four nucleobases and corresponding nucleosides forming the building blocks of deoxyribose nucleic acid (DNA). We observe numerous distinct spectral features with large differences between the molecules in both frequency-dependent absorption coefficient and index of refraction. Assisted by results from density-functional calculations we interpret the origin of the observed resonances as vibrations of hydrogen bonds between the molecules

  3. Global bending quantum number and the absence of monodromy in the HCN-CNH molecule

    NARCIS (Netherlands)

    Efstathiou, K; Joyeux, M; Sadovskií, D. A.

    We introduce and analyze a model system based on a deformation of a spherical pendulum that can be used to reproduce large amplitude bending vibrations of flexible triatomic molecules with two stable linear equilibria. On the basis of our model and the recent vibrational potential [ J. Chem. Phys.

  4. Vibration transducer calibration techniques

    Science.gov (United States)

    Brinkley, D. J.

    1980-09-01

    Techniques for the calibration of vibration transducers used in the Aeronautical Quality Assurance Directorate of the British Ministry of Defence are presented. Following a review of the types of measurements necessary in the calibration of vibration transducers, the performance requirements of vibration transducers, which can be used to measure acceleration, velocity or vibration amplitude, are discussed, with particular attention given to the piezoelectric accelerometer. Techniques for the accurate measurement of sinusoidal vibration amplitude in reference-grade transducers are then considered, including the use of a position sensitive photocell and the use of a Michelson laser interferometer. Means of comparing the output of working-grade accelerometers with that of previously calibrated reference-grade devices are then outlined, with attention given to a method employing a capacitance bridge technique and a method to be used at temperatures between -50 and 200 C. Automatic calibration procedures developed to speed up the calibration process are outlined, and future possible extensions of system software are indicated.

  5. Off-resonant vibrational excitation: Orientational dependence and spatial control of photofragments

    DEFF Research Database (Denmark)

    Machholm, Mette; Henriksen, Niels Engholm

    2000-01-01

    Off-resonant and resonant vibrational excitation with short intense infrared (IR) laser pulses creates localized oscillating wave packets, but differs by the efficiency of the excitation and surprisingly by the orientational dependence. Orientational selectivity of the vibrational excitation...... of randomly oriented heteronuclear diatomic molecules can be obtained under simultaneous irradiation by a resonant and an off-resonant intense IR laser pulse: Molecules with one initial orientation will be vibrationally excited, while those with the opposite orientation will be at rest. The orientation-dependent...... distribution. (C) 2000 American Institute of Physics....

  6. El hidrógeno y la energía

    OpenAIRE

    Aurelio Mendoza Medellín

    2006-01-01

    El hidrógeno es el elemento más simple, pero es fundamental para la vida. En el futuro sustituirá a los combustibles fósiles como fuente de energía para las máquinas hechas por el hombre. Hoy en día su uso es muy caro, pero ya existen motores que trabajan quemando este gas. En el sol la fusión de hidrógeno libera cantidades inconmensurables de energía, que en parte es captada por los cloroplastos, que la transforman en la energía química contenida en los carbohidratos resultantes de la fotosí...

  7. El hidrógeno y la energía

    OpenAIRE

    Aurelio Mendoza Medellín

    2006-01-01

    El hidrógeno es el elemento más simple, pero es fundamental para la vida. En el futuro sustituirá a los combustibles fósiles como fuente de energía para las máquinas hechas por el hombre. Hoy en día su uso es muy caro, pero ya existen motores que trabajan quemando este gas. En el sol la fusión de hidrógeno libera cantidades inconmensurables de energía, que en parte es captada por los cloroplastos, que la transforman en la energía química contenida en los carbohidratos resultantes ...

  8. Los balances energéticos en la producción agropecuaria.

    OpenAIRE

    Yepes Jaramillo, Guillermo; Martínez Bustamante, Enrique

    2011-01-01

    A través de este ensayo se presenta otro enfoque de análisis de la energía utilizada por los vegetales para la producción agraria. Se parte de los conceptos fundamentales relacionados con la termodinámica y la manera como el flujo de energía incide sobre el follaje de la vegetación y se distribuye, a través de las hojas, en todo el dosel de comunidades de plantas. La vida en la tierra es mantenida por el flujo de energía radiado por el sol y que entra en la biosfera. Por medio de la fotosínte...

  9. Stabilizing photoassociated Cs2 molecules by optimal control

    International Nuclear Information System (INIS)

    Zhang Wei; Xie Ting; Huang Yin; Wang Gao-Ren; Cong Shu-Lin

    2013-01-01

    We demonstrate theoretically that photoassociated molecules can be stabilized to deeply bound states. This process is achieved by transferring the population from the outer well to the inner well using the optimal control theory, the Cs 2 molecule is taken as an example. Numerical calculations show that weakly bound molecules formed in the outer well by a pump pulse can be compressed to the inner well via a vibrational level of the ground electronic state as an intermediary by an additionally optimized laser pulse. The positively chirped pulse can enhance the population of the target state. With a transform-limited dump pulse, nearly all the photoassociated molecules in the inner well of the excited electronic state can be transferred to the deeply vibrational level of the ground electronic state. (atomic and molecular physics)

  10. Layers of Cold Dipolar Molecules in the Harmonic Approximation

    DEFF Research Database (Denmark)

    R. Armstrong, J.; Zinner, Nikolaj Thomas; V. Fedorov, D.

    2012-01-01

    We consider the N-body problem in a layered geometry containing cold polar molecules with dipole moments that are polarized perpendicular to the layers. A harmonic approximation is used to simplify the hamiltonian and bound state properties of the two-body inter-layer dipolar potential are used...... to adjust this effective interaction. To model the intra-layer repulsion of the polar molecules, we introduce a repulsive inter-molecule potential that can be parametrically varied. Single chains containing one molecule in each layer, as well as multi-chain structures in many layers are discussed...... and their energies and radii determined. We extract the normal modes of the various systems as measures of their volatility and eventually of instability, and compare our findings to the excitations in crystals. We find modes that can be classified as either chains vibrating in phase or as layers vibrating against...

  11. Hydrogen molecules and hydrogen-related defects in crystalline silicon

    Science.gov (United States)

    Fukata, N.; Sasaki, S.; Murakami, K.; Ishioka, K.; Nakamura, K. G.; Kitajima, M.; Fujimura, S.; Kikuchi, J.; Haneda, H.

    1997-09-01

    We have found that hydrogen exists in molecular form in crystalline silicon treated with hydrogen atoms in the downstream of a hydrogen plasma. The vibrational Raman line of hydrogen molecules is observed at 4158 cm-1 for silicon samples hydrogenated between 180 and 500 °C. The assignment of the Raman line is confirmed by its isotope shift to 2990 cm-1 for silicon treated with deuterium atoms. The Raman intensity has a maximum for hydrogenation at 400 °C. The vibrational Raman line of the hydrogen molecules is broad and asymmetric. It consists of at least two components, possibly arising from hydrogen molecules in different occupation sites in crystalline silicon. The rotational Raman line of hydrogen molecules is observed at 590 cm-1. The Raman band of Si-H stretching is observed for hydrogenation temperatures between 100 and 500 °C and the intensity has a maximum for hydrogenation at 250 °C.

  12. Stabilizing photoassociated Cs2 molecules by optimal control

    Science.gov (United States)

    Zhang, Wei; Xie, Ting; Huang, Yin; Wang, Gao-Ren; Cong, Shu-Lin

    2013-01-01

    We demonstrate theoretically that photoassociated molecules can be stabilized to deeply bound states. This process is achieved by transferring the population from the outer well to the inner well using the optimal control theory, the Cs2 molecule is taken as an example. Numerical calculations show that weakly bound molecules formed in the outer well by a pump pulse can be compressed to the inner well via a vibrational level of the ground electronic state as an intermediary by an additionally optimized laser pulse. The positively chirped pulse can enhance the population of the target state. With a transform-limited dump pulse, nearly all the photoassociated molecules in the inner well of the excited electronic state can be transferred to the deeply vibrational level of the ground electronic state.

  13. Super-multiplex vibrational imaging

    Science.gov (United States)

    Wei, Lu; Chen, Zhixing; Shi, Lixue; Long, Rong; Anzalone, Andrew V.; Zhang, Luyuan; Hu, Fanghao; Yuste, Rafael; Cornish, Virginia W.; Min, Wei

    2017-04-01

    The ability to visualize directly a large number of distinct molecular species inside cells is increasingly essential for understanding complex systems and processes. Even though existing methods have successfully been used to explore structure-function relationships in nervous systems, to profile RNA in situ, to reveal the heterogeneity of tumour microenvironments and to study dynamic macromolecular assembly, it remains challenging to image many species with high selectivity and sensitivity under biological conditions. For instance, fluorescence microscopy faces a ‘colour barrier’, owing to the intrinsically broad (about 1,500 inverse centimetres) and featureless nature of fluorescence spectra that limits the number of resolvable colours to two to five (or seven to nine if using complicated instrumentation and analysis). Spontaneous Raman microscopy probes vibrational transitions with much narrower resonances (peak width of about 10 inverse centimetres) and so does not suffer from this problem, but weak signals make many bio-imaging applications impossible. Although surface-enhanced Raman scattering offers high sensitivity and multiplicity, it cannot be readily used to image specific molecular targets quantitatively inside live cells. Here we use stimulated Raman scattering under electronic pre-resonance conditions to image target molecules inside living cells with very high vibrational selectivity and sensitivity (down to 250 nanomolar with a time constant of 1 millisecond). We create a palette of triple-bond-conjugated near-infrared dyes that each displays a single peak in the cell-silent Raman spectral window; when combined with available fluorescent probes, this palette provides 24 resolvable colours, with the potential for further expansion. Proof-of-principle experiments on neuronal co-cultures and brain tissues reveal cell-type-dependent heterogeneities in DNA and protein metabolism under physiological and pathological conditions, underscoring the

  14. Long-Lived Feshbach Molecules in a Three-Dimensional Optical Lattice

    International Nuclear Information System (INIS)

    Thalhammer, G.; Winkler, K.; Lang, F.; Schmid, S.; Denschlag, J. Hecker; Grimm, R.

    2006-01-01

    We have created and trapped a pure sample of 87 Rb 2 Feshbach molecules in a three-dimensional optical lattice. Compared to previous experiments without a lattice, we find dramatic improvements such as long lifetimes of up to 700 ms and a near unit efficiency for converting tightly confined atom pairs into molecules. The lattice shields the trapped molecules from collisions and, thus, overcomes the problem of inelastic decay by vibrational quenching. Furthermore, we have developed an advanced purification scheme that removes residual atoms, resulting in a lattice in which individual sites are either empty or filled with a single molecule in the vibrational ground state of the lattice

  15. Recovering Intrinsic Fragmental Vibrations Using the Generalized Subsystem Vibrational Analysis.

    Science.gov (United States)

    Tao, Yunwen; Tian, Chuan; Verma, Niraj; Zou, Wenli; Wang, Chao; Cremer, Dieter; Kraka, Elfi

    2018-05-08

    Normal vibrational modes are generally delocalized over the molecular system, which makes it difficult to assign certain vibrations to specific fragments or functional groups. We introduce a new approach, the Generalized Subsystem Vibrational Analysis (GSVA), to extract the intrinsic fragmental vibrations of any fragment/subsystem from the whole system via the evaluation of the corresponding effective Hessian matrix. The retention of the curvature information with regard to the potential energy surface for the effective Hessian matrix endows our approach with a concrete physical basis and enables the normal vibrational modes of different molecular systems to be legitimately comparable. Furthermore, the intrinsic fragmental vibrations act as a new link between the Konkoli-Cremer local vibrational modes and the normal vibrational modes.

  16. Eficiencia energética de los edificios: repercusión medioambiental

    Directory of Open Access Journals (Sweden)

    Maria Nieves Pacheco Jiménez

    2009-06-01

    Full Text Available Los recientes Planes, Estrategias y normas atinentes al fomento de la eficiencia energética en los edificios1 nacen en un contexto de preocupación por el cambio climático y sus consecuencias. Todos ellos persiguen la reducción de costes energéticos y la promoción de la sostenibilidad económica, política y ambiental. Un reflejo de esta inquietud por el bajo impacto ambiental puede observarse en el sector de la vivienda, cuyo consumo final de energía es muy elevado, y en la consiguiente intención de construir edificios bioclimáticos que aprovechen la energía del entorno. En aras a la consecución de estos objetivos, el Plan de Acción 2008-2012 impulsa una serie de medidas que recaen sobre el sector transporte, la industria, el sector residencial y el sector terciario, articulándose en torno a cuatro líneas de actuación: transversal, de movilidad, de edificios y de ahorro eléctrico. Este estudio aborda las pautas de ahorro y eficiencia energética propuestas para los edificios, tanto existentes como de nueva construcción, así como residenciales y del sector terciario. Para ello se hace imprescindible la remisión al concepto de “calidad” de los edificios, contemplado en la propia Exposición de Motivos de la Ley 38/1999, de Ordenación de la Edificación, y ligado estrechamente a la eficiencia energética de aquéllos.

  17. Vibrations in orthopedics.

    Science.gov (United States)

    Nokes, L D; Thorne, G C

    1988-01-01

    Measurements of various mechanical properties of skeletal material using vibration techniques have been reported. The purposes of such investigations include the monitoring of pathogenic disorders such as osteoporosis, the rate and extent of fracture healing, and the status of internal fixations. Early investigations pioneered the application of conventional vibration measurement equipment to biological systems. The more recent advent of the microcomputer has made available to research groups more sophisticated techniques for data acquisition and analysis. The economical advantages of such equipment has led to the development of portable research instrumentation which lends itself to use in a clinical environment. This review article reports on the developments and progression of the various vibrational techniques and theories as applied to musculoskeletal systems.

  18. Resonant inelastic collisions of electrons with diatomic molecules

    International Nuclear Information System (INIS)

    Houfek, Karel

    2012-01-01

    In this contribution we give a review of applications of the nonlocal resonance theory which has been successfully used for treating the nuclear dynamics of low-energy electron collisions with diatomic molecules over several decades. We give examples and brief explanations of various structures observed in the cross sections of vibrational excitation and dissociative electron attachment to diatomic molecules such as threshold peaks, boomerang oscillations below the dissociative attachment threshold, or outer-well resonances.

  19. Resonant inelastic collisions of electrons with diatomic molecules

    Energy Technology Data Exchange (ETDEWEB)

    Houfek, Karel, E-mail: karel.houfek@gmail.com [Institute of Theoretical Physics, Faculty of Mathematics and Physics, Charles University, V Holesovickach 2, 180 00 Prague 8 (Czech Republic)

    2012-05-15

    In this contribution we give a review of applications of the nonlocal resonance theory which has been successfully used for treating the nuclear dynamics of low-energy electron collisions with diatomic molecules over several decades. We give examples and brief explanations of various structures observed in the cross sections of vibrational excitation and dissociative electron attachment to diatomic molecules such as threshold peaks, boomerang oscillations below the dissociative attachment threshold, or outer-well resonances.

  20. Climatización de una vivienda con energía geotérmica

    OpenAIRE

    González Elosua, Ignacio Isaías

    2013-01-01

    El presente proyecto consiste en el estudio, diseño y definición de una instalación de aprovechamiento de energía geotérmica para la climatización a lo largo de todo el año de una vivienda unifamiliar en la localidad de Fornells en el término municipal de Es Mercadal, en Menorca. Para ello, se ha calculado la demanda energética térmica requerida por la vivienda debido a su forma arquitectónica, materiales empleados y necesidades interiores, siguiendo criterios legales, funcionales y constr...

  1. La Reforma Energética: a 20 años del TLCAN

    OpenAIRE

    Vargas, Rosío

    2015-01-01

    La visita del presidente estadounidense Barack Obama a México, en mayo de 2013, fue la ocasión para buscar el acceso al petróleo y gas mexicano, amparado en el argumento de los 20 años del TLCAN, bajo "la necesidad" de su relanzamiento. Cabilderos nacionales y extranjeros se dieron a la tarea de elaborar la estrategia para la apertura total del sector energético mexicano bajo la propuesta de la Reforma Energética mexicana, aprobada el 20 de diciembre de 2013. En las modificaciones constitucio...

  2. Mejora de la eficiencia energética en una vivienda

    OpenAIRE

    Díaz Oliva, Marc

    2013-01-01

    El objetivo de este proyecto es la mejora de la eficiencia energética de la vivienda este objetivo me viene por una estancia en Alemania donde todas las viviendas están concebidas para obtener la máxima eficiencia y por consiguiente ahorro una de las cosas que más me llamo la atención fue la implantación de energías renovables ya que las horas de luz son menores a las obtenidas en España por este motivo quise comprobar cuanto se podía mejorar la eficiencia en mi vivienda y s...

  3. Estudio comparativo de eficiencia energética: Fachada ventilada frente a fachada vegetal

    OpenAIRE

    Azkorra Larrinaga, Zaloa

    2015-01-01

    398 p. + anexos En la actualidad se desarrollan multitud de investigaciones relacionadas con la rehabilitación energética lo que la ha convertido en un campo emergente en el sector de la construcción y de la arquitectura.El objetivo general de la tesis es evaluar la aplicabilidad de diferentes sistemas pasivos de rehabilitación de fachadas (fachada ventilada y fachada vegetal) y analizar los beneficios de la incorporación de dichos sistemas en el ahorro energético de edificios.Para ello, s...

  4. Energía de oleaje en la isla de Tenerife

    OpenAIRE

    Imaz Gómez, Mario

    2016-01-01

    El objeto de este proyecto es realizar todos los estudios necesarios para la construcción de la primera fase de un parque de dispositivos de extracción de energía undimotriz que permita obtener información fiable y necesaria sobre el comportamiento de los dispositivos en grupo y poder ver si el rendimiento es el esperado para posteriormente realizar las otras dos fases con el fin de abastecer a la ciudad de Puerto de la Cruz, situada en el norte de la isla de Tenerife. Actualmente las energía...

  5. Sustentabilidad empresarial, seguridad energética y ética ambiental en Chile

    OpenAIRE

    Suárez,Andrés

    2013-01-01

    El artículo explora la relación entre sustentabilidad empresarial -asociada tanto a la rentabilidad financiera como a las relaciones con colectivos locales- y el medioambiente, en el contexto de una economía internacionalizada como la chilena. Asimismo, analiza conflictos recientes originados en Chile para la provisión de energía y las dificultades en la definición de una matriz energética, y, finalmente, la influencia de la ética ecológica para la preservación de los ecosistemas de alta biod...

  6. Proyectos pilotos WHIX de energía renovable y seguridad ambiental en El Salvador.

    OpenAIRE

    Ochoa Córdova, Carlos Roberto

    2008-01-01

    El Programa WHIX aporta proyectos de Energía y Medio Ambiente para abrir un diálogo entre los militares de la Región, organizaciones gubernamentales y no-gubernamentales y sus equivalentes en los EE.UU. Este programa cataliza proyectos de energía renovable y el medioambiente para demostrar y validar estas tecnologías en los países de la región. Al mismo tiempo provee un foro de intercambio internacional de las “Mejores Prácticas” y la oportunidad de trabajar en conjunto en promisorias investi...

  7. Cómo producen energía las células

    OpenAIRE

    Carlos Alberto Ordoñez

    2014-01-01

    El adenosín trifosfato (ATP), es la moneda energética de los seres vivos. Para poder ser sintetizado, los organismos requieren oxidar los sustratos energéticos de la dieta, proteínas, grasas y carbohidratos. Inicialmente estas sustancias tienen vías metabólicas separadas hasta alcanzar en su degradación un metabolito común que es el acetil CoA. A partir de este punto entran al ciclo de Krebs, con producción de CO2 e hidrogeniones, estos últimos se transportan por óxido reducción a la cadena r...

  8. Problemas institucionales de las energías renovables en México

    OpenAIRE

    Samuel Brugger; Ma. Elena Nancy Dávila Moreno; Manuel Francisco Llamas Galván

    2011-01-01

    Este ensayo trata de explicar los problemas institucionales y jurídicos que han limitado el aprovechamiento de dichas energías alternativas. El trabajo presenta la situación actual de México; después analiza el potencial que tiene el país. De ahí se pasa al estudio de la problemática institucional y jurídica que no ha logrado fomentar la promoción de energías renovables en México.

  9. Limitaciones para el desarrollo de energías renovables en Argentina

    OpenAIRE

    Marina Yesica Recalde; Daniel Hugo Bouille; Leónidas Osvaldo Girardin

    2015-01-01

    En las últimas décadas las energías renovables han cobrado impulso a nivel mundial con un significativo impacto sobre el desarrollo sustentable de las naciones. Si bien diferentes trabajos analizan la eficiencia de políticas e instrumentos para la promoción de dichas fuentes, la mayoría de las veces se deja de lado el análisis de cómo el contexto en el cual las políticas son implementadas determina su performance. En este trabajo se analiza el desarrollo de las energías renovables en el merca...

  10. Análisis armónico de compensadores de energía reactiva

    OpenAIRE

    González Hernández, Jaime

    2011-01-01

    Desde la implantación de la generación y distribución de la energía eléctrica en corriente alterna, la energía reactiva ha sido un factor clave en el diseño y explotación de los consumos y redes eléctricas. El carácter reactivo (inductivo) que presentan, en general, los consumos y los elementos de las redes eléctricas han hecho aparecer a lo largo del tiempo distintos dispositivos y técnicas que buscan "compensar" ese carácter reactivo.

  11. Problemas institucionales de las energías renovables en México

    Directory of Open Access Journals (Sweden)

    Samuel Brugger

    2011-09-01

    Full Text Available Este ensayo trata de explicar los problemas institucionales y jurídicos que han limitado el aprovechamiento de dichas energías alternativas. El trabajo presenta la situación actual de México; después analiza el potencial que tiene el país. De ahí se pasa al estudio de la problemática institucional y jurídica que no ha logrado fomentar la promoción de energías renovables en México.

  12. Vibrational spectra of aminoacetonitrile

    International Nuclear Information System (INIS)

    Bak, B.; Hansen, E.L.; Nicolaisen, F.M.; Nielsen, O.F.

    1975-01-01

    The preparation of pure, stable aminoacetonitrile(1-amino, 1'-cyanomethane)CH 2 NH 2 CN (1) is described. The Raman spectrum, now complete, and a novel infrared spectrum extending over the 50-3600 cm -1 region are reported. A tentative normal vibration analysis is presented and supported by Raman and infrared data from the spectra of CH 2 NHDCN (2) and CH 2 ND 2 CN (3). The predominance of the trans rotamer may be attributed to intramolecular hydrogen bonding but this is too unimportant to influence the vibrational frequencies of gaseous 1, 2, and 3. However, large gas/liquid frequency shifts occur. (author)

  13. Vibrations and waves

    CERN Document Server

    Kaliski, S

    2013-01-01

    This book gives a comprehensive overview of wave phenomena in different media with interacting mechanical, electromagnetic and other fields. Equations describing wave propagation in linear and non-linear elastic media are followed by equations of rheological models, models with internal rotational degrees of freedom and non-local interactions. Equations for coupled fields: thermal, elastic, electromagnetic, piezoelectric, and magneto-spin with adequate boundary conditions are also included. Together with its companion volume Vibrations and Waves. Part A: Vibrations this work provides a wealth

  14. Vibration Theory, Vol. 3

    DEFF Research Database (Denmark)

    Nielsen, Søren R. K.

    The present textbook has been written based on previous lecture notes for a course on stochastic vibration theory that is being given on the 9th semester at Aalborg University for M. Sc. students in structural engineering. The present 2nd edition of this textbook on linear stochastic vibration th...... theory is basically unchanged in comparison to the 1st edition. Only section 4.2 on single input - single output systems and chapter 6 on offshore structures have been modified in order to enhance the clearness....

  15. Molecule scattering from insulator and metal surfaces

    International Nuclear Information System (INIS)

    Moroz, Iryna; Ambaye, Hailemariam; Manson, J R

    2004-01-01

    Calculations are carried out and compared with data for the scattering of CH 4 molecules from a LiF(001) surface and for O 2 scattering from Al(111). The theory is a mixed classical-quantum formalism that includes energy and momentum transfers between the surface and projectile for translational and rotational motions as well as internal mode excitation of the projectile molecule. The translational and rotational degrees of freedom couple most strongly to multiphonon excitations of the surface and are treated with classical dynamics. Internal vibrational excitations of the molecules are treated with a semiclassical formalism with extension to arbitrary numbers of modes and arbitrary quantum numbers. Calculations show good agreement for the dependence on incident translational energy, incident beam angle and surface temperature when compared with data for energy-resolved intensity spectra and angular distributions

  16. Estudio de viabilidad de un sistema de generación de energía eléctrica basado en energías renovables para países en vías de desarrollo

    OpenAIRE

    Villanueva Fernández, Gemma

    2010-01-01

    En este proyecto, primero se realiza una pequeña introducción para que el lector adquiera unos conocimientos mínimos sobre las energías renovables. Posteriormente, se describe los conceptos básicos de la energía solar fotovoltaica y los materiales usados en la misma. La energía solar fotovoltaica, es una transformación de la energía luminosa en energía eléctrica. El material más utilizado en la fabricación de los paneles solares es el silicio. De igual forma, se describe conceptos básicos de ...

  17. Rotational dependence of Fermi-type resonance interactions in molecules

    Science.gov (United States)

    Mikhailov, Vladimir M.; Smirnov, M. A.

    1997-03-01

    In Pasadena, (Milliken Lab., USA, 1930) F. Rossetti has observed in Raman spectrum of carbon-dioxide molecule the full symmetric vibration of carbon dioxide appeared as the group of four near lying lines instead of the waited single line. The true interpretation of this enigmatic effect (in that time) was given by E. Fermi -- accidental degeneration of the first excited state of the full symmetric vibration in carbon dioxide. It was the first example of the event observed later in various organic molecules. This event was named as resonance Fermi. The rotational dependence of Fermi type resonance interactions in quasirigid molecules in dominant approximation can be selected in an expansion of the effective vibration-rotation Hamiltonian Hvib- roteff by the operator H(g)(Fermi) equals H30 plus (Sigma) nH3n(g). Let us consider in detail the problem of the construction of the effective vibration-rotational Hamiltonian HVR yields Heff from the point of view of various ordering schemes (grouping) of the vibrational-rotational interactions with sequential analysis of the choice of the convenient grouping adequate to the spectroscopic problem.

  18. Desarrollo e implantación de energías renovables: situación actual y tendencias

    OpenAIRE

    Picó Heras, Sergio

    2002-01-01

    En esta tesina se tratarán las posibilidades que ofrecen las energías renovables com base de una planificicación energética. El tema se enfocará tanto desde puntos de vista económicos, ambientales, técnicos, políticos, etc

  19. Vibration in car repair work.

    Science.gov (United States)

    Hansson, J E; Eklund, L; Kihlberg, S; Ostergren, C E

    1987-03-01

    The main objective of the study was to find efficient hand tools which caused only minor vibration loading. Vibration measurements were carried out under standardised working conditions. The time during which car body repairers in seven companies were exposed to vibration was determined. Chisel hammers, impact wrenches, sanders and saws were the types of tools which generated the highest vibration accelerations. The average daily exposure at the different garages ranged from 22 to 70 min. The risk of vibration injury is currently rated as high. The difference between the highest and lowest levels of vibration was considerable in most tool categories. Therefore the choice of tool has a major impact on the magnitude of vibration exposure. The importance of choosing the right tools and working methods is discussed and a counselling service on vibration is proposed.

  20. Maximizing semi-active vibration isolation utilizing a magnetorheological damper with an inner bypass configuration

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xian-Xu, E-mail: bai@hfut.edu.cn [Department of Vehicle Engineering, Hefei University of Technology, Hefei 230009 (China); Wereley, Norman M.; Hu, Wei [Department of Aerospace Engineering, University of Maryland, College Park, Maryland 20742 (United States)

    2015-05-07

    A single-degree-of-freedom (SDOF) semi-active vibration control system based on a magnetorheological (MR) damper with an inner bypass is investigated in this paper. The MR damper employing a pair of concentric tubes, between which the key structure, i.e., the inner bypass, is formed and MR fluids are energized, is designed to provide large dynamic range (i.e., ratio of field-on damping force to field-off damping force) and damping force range. The damping force performance of the MR damper is modeled using phenomenological model and verified by the experimental tests. In order to assess its feasibility and capability in vibration control systems, the mathematical model of a SDOF semi-active vibration control system based on the MR damper and skyhook control strategy is established. Using an MTS 244 hydraulic vibration exciter system and a dSPACE DS1103 real-time simulation system, experimental study for the SDOF semi-active vibration control system is also conducted. Simulation results are compared to experimental measurements.

  1. Nexo agua-energía: desde el nacimiento del río Llobregat hasta Manresa

    OpenAIRE

    Prieto Márquez, Kelly; Badia Padilla, Ester; Grau Vilalta, Maria Dolors

    2017-01-01

    En este trabajo se estudia el nexo agua-energía en el tramo del río Llobregat desde Castellar de N’hug hasta Manresa. Se lleva a cabo una evaluación de la cantidad de energía necesaria en las estaciones potabilizadoras y depuradoras para adecuar el agua del río, además de determinar la cantidad de energía que generan las centrales mini-hidroeléctricas. Estos dos valores de energía finales son comparados para demostrar si se consume más energía que la que se genera, o al contrario. Se estud...

  2. Structural Stability and Vibration

    DEFF Research Database (Denmark)

    Wiggers, Sine Leergaard; Pedersen, Pauli

    at the University of Southern Denmark, it reports on fundamental formulas and makes uses of graphical representation to promote understanding. Thanks to the emphasis put on analytical methods and numerical results, the book is meant to make students and engineers familiar with all fundamental equations...... and their derivation, thus stimulating them to write interactive and dynamic programs to analyze instability and vibrational modes....

  3. Vibrations and Eigenvalues

    Indian Academy of Sciences (India)

    The vibrating string problem is the source of much mathe- matics and physics. ... ing this science [mechanics],and the art of solving the problems pertaining to it, to .... used tools for finding maxima and minima of functions of several variables.

  4. Heat exchanger vibration

    International Nuclear Information System (INIS)

    Richards, D.J.W.

    1977-01-01

    The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration

  5. Man-Induced Vibrations

    DEFF Research Database (Denmark)

    Jönsson, Jeppe; Hansen, Lars Pilegaard

    1994-01-01

    work has been done on the measurement of the exact load functions and related reponse analysis. A recent work using a spectral description has been performed by Per-Erik Erikson and includes a good literature survey. Bachmann and Ammann give a good overview of vibrations caused by human activity. Other...

  6. Heat exchanger vibration

    Energy Technology Data Exchange (ETDEWEB)

    Richards, D J.W. [CERL, CEGB, Leatherhead, Surrey (United Kingdom)

    1977-12-01

    The heat exchangers of various types are common items of plant in the generation and transmission of electricity. The amount of attention given to the flow-induced vibrations of heat exchangers by designers is usually related to the operational history of similar items of plant. Consequently, if a particular design procedure yields items of plant which behave in a satisfactory manner during their operational life, there is little incentive to improve or refine the design procedure. On the other hand, failures of heat exchangers clearly indicate deficiencies in the design procedures or in the data available to the designer. When such failures are attributable to flow-induced vibrations, the identification of the mechanisms involved is a prime importance. Ideally, basic research work provides the background understanding and the techniques necessary to be able to identify the important mechanisms. In practice, the investigation of a flow-induced vibration problem may identify the presence of mechanisms but may not be able to quantify their effects adequately. In these circumstances the need for additional work is established and the objectives of the research programme emerge. The purpose of this paper is to outline the background to the current research programme at C.E.R.L. on heat exchanger vibration.

  7. High-Temperature Vibration Damper

    Science.gov (United States)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  8. Mathematical Modelling and Parameter Identification of an Electro-Magneto-Mechanical Actuator for Vibration Control

    DEFF Research Database (Denmark)

    Darula, Radoslav; Stein, George Juraj; Kallesøe, Carsten Skovmose

    2012-01-01

    . The electric circuit is closed with a shunt resistance connected to the electromagnet. The current induced in the circuit generates additional alternating magnetic force. This force counteracts the original vibration and damps it. In this way the coupled electro-magneto-mechanical system suppresses the forced...... of the electromagnetic circuit in its various operational regimes. The parametric identification supplements mathematical derivations. The analyzed mechanical system is essentially a Single Degree-Of-Freedom (SDOF) oscillatory system augmented by magnetic force influence. The additional magnetic force is generated...... by an electromagnet with armature. The electromagnet is energized by a constant voltage source. The SDOF system is excited by a harmonic force causing vibration of the armature. Due to the reluctance variation of the air gap of the magnetic circuit alternating voltage is generated across the coil terminals...

  9. Examining the impact of harmonic correlation on vibrational frequencies calculated in localized coordinates

    Energy Technology Data Exchange (ETDEWEB)

    Hanson-Heine, Magnus W. D., E-mail: magnus.hansonheine@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom)

    2015-10-28

    Carefully choosing a set of optimized coordinates for performing vibrational frequency calculations can significantly reduce the anharmonic correlation energy from the self-consistent field treatment of molecular vibrations. However, moving away from normal coordinates also introduces an additional source of correlation energy arising from mode-coupling at the harmonic level. The impact of this new component of the vibrational energy is examined for a range of molecules, and a method is proposed for correcting the resulting self-consistent field frequencies by adding the full coupling energy from connected pairs of harmonic and pseudoharmonic modes, termed vibrational self-consistent field (harmonic correlation). This approach is found to lift the vibrational degeneracies arising from coordinate optimization and provides better agreement with experimental and benchmark frequencies than uncorrected vibrational self-consistent field theory without relying on traditional correlated methods.

  10. Double ionization of molecule H2 in intense ultrashort laser fields

    International Nuclear Information System (INIS)

    Le, Thu-Thuy; Nguyen, Ngoc-Ty

    2015-01-01

    By solving numerically the time-dependent Schrödinger equation (TDSE), we have calculated the double ionization probability when a vibrating hydrogen molecule interacts with intense ultrashort laser pulses. The results show that in the case of vibrating nuclei the double ionization probability is higher than that of the fixed nuclei. Additionally, the double ionization probability is larger if the molecule is vibrating in a higher level. This is due to the decreasing of ionization potential when the inter-nuclei separation increases. (paper)

  11. El hidrógeno y la energía

    Directory of Open Access Journals (Sweden)

    Aurelio Mendoza Medellín

    2006-01-01

    Full Text Available El hidrógeno es el elemento más simple, pero es fundamental para la vida. En el futuro sustituirá a los combustibles fósiles como fuente de energía para las máquinas hechas por el hombre. Hoy en día su uso es muy caro, pero ya existen motores que trabajan quemando este gas. En el sol la fusión de hidrógeno libera cantidades inconmensurables de energía, que en parte es captada por los cloroplastos, que la transforman en la energía química contenida en los carbohidratos resultantes de la fotosíntesis. Esto implica la transferencia del hidrógeno del agua al dióxido de carbono. Los animales liberan la energía de los combustibles biológicos revirtiendo dicha reacción a través del metabolismo oxidativo, la cadena respiratoria y la fosforilación oxidativa. El hidrógeno es vital para producir ATP y por lo tanto para la vida.

  12. Effectiveness of the Energize Elementary School Program to Improve Diet and Exercise

    Science.gov (United States)

    Herbert, Patrick C.; Lohrmann, David K.; Seo, Dong-Chul; Stright, Anne D.; Kolbe, Lloyd J.

    2013-01-01

    Background: The rate of childhood obesity has more than tripled during the past 30?years. Research shows that prevention at an early age is more effective than treatment later in life. Energize is a multicomponent intervention incorporated into the school day that combines nutrition education and physical activity aimed at maintaining healthy…

  13. Gas exchange and leaf contents in bell pepper under energized water and biofertilizer doses

    Directory of Open Access Journals (Sweden)

    Francisca R. M. Borges

    2016-06-01

    Full Text Available ABSTRACT The objective of this study was to evaluate the effect of energized water and bovine biofertilizer doses on the gas exchange and NPK contents in leaves of yellow bell pepper plants. The experiment was conducted at the experimental area of the Federal University of Ceará, in Fortaleza-CE, Brazil, from June to November 2011. The experiment was set in a randomized block design, in a split-plot scheme; the plots were composed of treatments with energized and non-energized water and the subplots of five doses of liquid biofertilizer (0, 250, 500, 750 and 1000 mL plant-1 week-1. The following variables were analyzed: transpiration, stomatal conductance, photosynthesis and leaf contents of nitrogen (N, phosphorus (P and potassium (K. Water energization did not allow significant increases in the analyzed variables. The use of biofertilizer as the only source of fertilization was sufficient to provide the nutrients N, P and K at appropriate levels for the bell pepper crop.

  14. Proyecto Energético Palmdale; Decisión del Permiso Final

    Science.gov (United States)

    Proyecto Energético Palmdale: EPA Región 9 por el presente emite aviso de su decisión final, el cumplimiento con la Ley Federal de Aire Limpio, para la construcción de una planta generadora de electricidad de ciclo combinado y alimentada por gas natural

  15. Implicaciones ambientales de las tecnologías de energía renovable

    Directory of Open Access Journals (Sweden)

    Jan Mahirt-Smith

    2011-12-01

    Full Text Available Las tecnologías de energía renovable como la eólica, la solar y la biomasa, hacen un uso del suelo más intenso que las de combustibles fósiles tradicionales y, geográficamente, sus implicaciones ambientales son más heterogéneas, por lo que presentan un gran desafío para las técnicas de evaluación de su ciclo de vida. Este trabajo presenta los resultados de una investigación bibliográfica alrededor de los siguientes temas: 1 cambios en el uso del suelo debido a la mayor producción de energía renovable; 2 impactos del uso de suelo; 3 variabilidad geográfica en el inventario de datos; y 4 efectos de la distribución de energía. Además, se revisa el grado de investigación que actualmente se aplica acerca de las tecnologías de energía renovable en campos como el eólico, el solar y la bioenergía y en la evaluación del ciclo de vida en general.

  16. The effects of vibration-reducing gloves on finger vibration

    Science.gov (United States)

    Welcome, Daniel E.; Dong, Ren G.; Xu, Xueyan S.; Warren, Christopher; McDowell, Thomas W.

    2015-01-01

    Vibration-reducing (VR) gloves have been used to reduce the hand-transmitted vibration exposures from machines and powered hand tools but their effectiveness remains unclear, especially for finger protection. The objectives of this study are to determine whether VR gloves can attenuate the vibration transmitted to the fingers and to enhance the understanding of the mechanisms of how these gloves work. Seven adult male subjects participated in the experiment. The fixed factors evaluated include hand force (four levels), glove condition (gel-filled, air bladder, no gloves), and location of the finger vibration measurement. A 3-D laser vibrometer was used to measure the vibrations on the fingers with and without wearing a glove on a 3-D hand-arm vibration test system. This study finds that the effect of VR gloves on the finger vibration depends on not only the gloves but also their influence on the distribution of the finger contact stiffness and the grip effort. As a result, the gloves increase the vibration in the fingertip area but marginally reduce the vibration in the proximal area at some frequencies below 100 Hz. On average, the gloves reduce the vibration of the entire fingers by less than 3% at frequencies below 80 Hz but increase at frequencies from 80 to 400 Hz. At higher frequencies, the gel-filled glove is more effective at reducing the finger vibration than the air bladder-filled glove. The implications of these findings are discussed. Relevance to industry Prolonged, intensive exposure to hand-transmitted vibration can cause hand-arm vibration syndrome. Vibration-reducing gloves have been used as an alternative approach to reduce the vibration exposure. However, their effectiveness for reducing finger-transmitted vibrations remains unclear. This study enhanced the understanding of the glove effects on finger vibration and provided useful information on the effectiveness of typical VR gloves at reducing the vibration transmitted to the fingers. The new

  17. Redes de energía en la Argentina del siglo XXI. Proyectos locales innovadores

    Directory of Open Access Journals (Sweden)

    Silvina Carrizo

    2015-04-01

    Full Text Available En Argentina se construyeron de forma pionera, extensas redes de electricidad, gas y combustibles. El 98% de los hogares están conectados a la red eléctrica y el 51% de la población tiene acceso al gas natural por red (INDEC 2012. A pesar de la cobertura energética amplia, aún persisten en el país algunas regiones -como el Noroeste de la Provincia de Buenos Aires NOBAdonde las redes no llegan o tienen menor densidad. La región NOBA, situada entre las ciudades de Rosario y Buenos Aires, que cuentan con infraestructura considerable para su aprovisionamiento, presenta redes eléctricas y gasíferas poco densas -especialmente hacia el interior- y escaso desarrollo de fuentes de energías alternativas. En materia de gas, faltan gasoductos troncales o regionales. En el sistema eléctrico, hay poca capacidad de generación y se necesita mayor interconexión. Desde distintos niveles se han promovido alternativas en materia de producción, transporte y distribución de energía, pero los avances aún no alcanzan para asegurar la resiliencia energética enla región NOBA. En un contexto de esta índole, actores locales se han organizado para satisfacer sus necesidades energéticas con proyectos nuevos de transporte de gas y de aprovechamiento de recursos locales renovables, con un potencial que aún no ha sido puesto en valor. Abordando proyectos energéticos locales y regionales, este trabajo propone reflexionar acerca de la nueva geografía que podría delinearse en la producción y circulación de la energía, más flexible, fiable y sustentable, fomentando la innovación y la productividad, así como la equidad regional.

  18. Assessing potential impacts of energized submarine power cables on crab harvests

    Science.gov (United States)

    Love, Milton S.; Nishimoto, Mary M.; Clark, Scott; McCrea, Merit; Bull, Ann Scarborough

    2017-12-01

    Offshore renewable energy facilities transmit electricity to shore through submarine power cables. Electromagnetic field emissions (EMFs) are generated from the transmission of electricity through these cables, such as the AC inter-array (between unit) and AC export (to shore) cables often used in offshore energy production. The EMF has both an electric component and a magnetic component. While sheathing can block the direct electric field, the magnetic field is not blocked. A concern raised by fishermen on the Pacific Coast of North America is that commercially important Dungeness crab (Metacarcinus magister Dana, 1852)) might not cross over an energized submarine power cable to enter a baited crab trap, thus potentially reducing their catch. The presence of operating energized cables off southern California and in Puget Sound (cables that are comparable to those within the arrays of existing offshore wind energy devices) allowed us to conduct experiments on how energized power cables might affect the harvesting of both M. magister and another commercially important crab species, Cancer productus Randall, 1839. In this study we tested the questions: 1) Is the catchability of crabs reduced if these animals must traverse an energized power cable to enter a trap and 2) if crabs preferentially do not cross an energized cable, is it the cable structure or the EMF emitted from that cable that deters crabs from crossing? In field experiments off southern California and in Puget Sound, crabs were given a choice of walking over an energized power cable to a baited trap or walking directly away from that cable to a second baited trap. Based on our research we found no evidence that the EMF emitted by energized submarine power cables influenced the catchability of these two species of commercially important crabs. In addition, there was no difference in the crabs' responses to lightly buried versus unburied cables. We did observe that, regardless of the position of the cable

  19. Sum frequency generation for surface vibrational spectroscopy

    International Nuclear Information System (INIS)

    Hunt, J.H.; Guyot-Sionnest, P.; Shen, Y.R.

    1987-01-01

    Surface vibrational spectroscopy is one of the best means for characterizing molecular adsorbates. For this reason, many techniques have been developed in the past. However, most of them suffer from poor sensitivity, low spectral and temporal resolution, and applications limited to vacuum solid interfaces. Recently, the second harmonic generation (SHG) technique was proved repeatedly to be a simple but versatile surface probe. It is highly sensitive and surface specific; it is also capable of achieving high temporal, spatial, and spectral resolution. Being an optical technique, it can be applied to any interface accessible by light. The only serious drawback is its lack of molecular selectivity. An obvious remedy is the extension of the technique to IR-visible sum frequency generation (SFG). Surface vibrational spectroscopy with submonolayer sensitivity is then possible using SFG with the help of a tunable IR laser. The authors report here an SFG measurement of the C-H stretch vibration of monolayers of molecules at air-solid and air-liquid interfaces

  20. Eckart frame vibration-rotation Hamiltonians: Contravariant metric tensor

    International Nuclear Information System (INIS)

    Pesonen, Janne

    2014-01-01

    Eckart frame is a unique embedding in the theory of molecular vibrations and rotations. It is defined by the condition that the Coriolis coupling of the reference structure of the molecule is zero for every choice of the shape coordinates. It is far from trivial to set up Eckart kinetic energy operators (KEOs), when the shape of the molecule is described by curvilinear coordinates. In order to obtain the KEO, one needs to set up the corresponding contravariant metric tensor. Here, I derive explicitly the Eckart frame rotational measuring vectors. Their inner products with themselves give the rotational elements, and their inner products with the vibrational measuring vectors (which, in the absence of constraints, are the mass-weighted gradients of the shape coordinates) give the Coriolis elements of the contravariant metric tensor. The vibrational elements are given as the inner products of the vibrational measuring vectors with themselves, and these elements do not depend on the choice of the body-frame. The present approach has the advantage that it does not depend on any particular choice of the shape coordinates, but it can be used in conjunction with all shape coordinates. Furthermore, it does not involve evaluation of covariant metric tensors, chain rules of derivation, or numerical differentiation, and it can be easily modified if there are constraints on the shape of the molecule. Both the planar and non-planar reference structures are accounted for. The present method is particular suitable for numerical work. Its computational implementation is outlined in an example, where I discuss how to evaluate vibration-rotation energies and eigenfunctions of a general N-atomic molecule, the shape of which is described by a set of local polyspherical coordinates

  1. Simulations of vibrational relaxation in dense molecular fluids

    International Nuclear Information System (INIS)

    Holian, B.L.

    1985-07-01

    In the understanding of high-temperatre and -pressure chemistry in explosives, first step is the study of the transfer of energy from translational degrees of freedom into internal vibrations of the molecules. We present new methods using nonequilibrium molecular dynamics (NEMD) for measuring vibrational relaxation in a diatomic fluid, where we expect a classical treatment of many-body collisions to be relevant because of the high densities (2 to 3 times compressed compared to the normal fluid) and high temperatures (2000 to 4000 K) involved behind detonation waves. NEMD techniques are discussed, including their limitations, and qualitative results presented

  2. Stokes-attenuated tunneling ionization of molecules

    Science.gov (United States)

    Kornev, Aleksei S.; Zon, Boris A.

    2018-03-01

    We set forth the quantum theory of ionic vibrational-level population by means of tunneling ionization of a molecule. Specific calculations are carried out for the H2 molecule. The results are in qualitative agreement with the experimental data [X. Urbain et al., Phys. Rev. Lett. 92, 163004 (2004), 10.1103/PhysRevLett.92.163004]. Our account for the excited vibrational levels reveals an interplay of two tendencies which contribute to the ionization rate: (i) It decreases due to additional energy absorption needed to populate these states and (ii) it increases together with the Franck-Condon factors which are large for these states. We show that these two tendencies practically compensate each other. The average quantitative disagreement between the theory and experiment amounts to ˜30 %. The same disagreement takes place when using the frozen approximation for the description of the nuclei motion. We demonstrated that the light-dressing effect for H2 leads to the dependence of the ionization rate on the angle between the molecule axis and the polarization vector of the radiation.

  3. Lifetime cost effectiveness of a through-school nutrition and physical programme: Project Energize.

    Science.gov (United States)

    Rush, Elaine; Obolonkin, Victor; McLennan, Stephanie; Graham, David; Harris, James D; Mernagh, Paul; Weston, Adéle R

    2014-01-01

    Project Energize, a multicomponent through-school physical activity and nutrition programme, is delivered to all primary school children in the Waikato region. The programme aim is to improve the overall health and reduce the rate of weight gain of all Waikato primary school children. An existing economic model was used to extrapolate the programme effects, initial costs, lifetime health treatment cost structures, quality-adjusted-life-years gained and increased life expectancy to the general and Māori child population of New Zealand. In March 2011, a sample of 2474 younger (7.58 ± 0.57 years, mean ± SD) and 2330 older (10.30 ± 0.51 years) children (36% Māori) attending Energize schools had body mass index measured and compared using mixed effect modelling with unEnergized comparison children from 2004 and 2006 from the same region. In 2011 the median body mass index reduction compared with the comparison younger children was -0.504 (90% CI -0.435 to -0.663) kg/m(2) and in the older children -0.551 (-0.456 to -0.789) kg/m(2). In 2010 there were 42,067 children attending Energize schools and in the same year NZ$1,891,175 was spent to deliver the programme; a cost of $44.96/child/year. Compared to the comparison children the increment in cost/quality-adjusted-life-year gained was $30,438 for the younger and $24,690 for the older children, and lower for Māori (younger $28,241, older $22,151) and for the middle socioeconomic status schools ($23,211, $17,891). Project Energize would improve quality and length of life and when compared with other obesity prevention programmes previously assessed with this model, it would be relatively cost-effective from the health treatment payer's perspective.

  4. La energía nuclear y la industria en Francia

    Directory of Open Access Journals (Sweden)

    Roux, A.

    1980-09-01

    Full Text Available In this article an analysis is made of the favorable effects for industry involved in the development of nuclear energy and the interaction between them. Reference is made to the problem of energy supply in France and the need for an effort in energy savings, to the development of new sources and priority in the establishment of an important program of nuclear power plants. Also, an analysis is made of the role of Industry, the Atomic Energy and Electricity Commission of France in the supply and processing of the nuclear materials. Finally, a general review of the manpower and technical means presently available is made, as well as an examination of the investments foreseen for local development of this energy.

    En este artículo se analizan los efectos favorables que para la Industria tiene el desarrollo de la energía nuclear y las interacciones entre ambas. Se hace referencia al problema del aprovisionamiento energético en Francia y a la necesidad de un esfuerzo en materia de ahorro de energía, al desarrollo de nuevas fuentes y a la prioridad en el establecimiento de un importante programa de centrales nucleares. También es analizado el papel de la Industria, la Comisaría de Energía Atómica y Electricidad de Francia en el abastecimiento y en la transformación de los materiales nucleares. Por último, se hace un repaso general de los medios humanos y técnicos con que se cuenta en la actualidad, así como de las inversiones previstas para un desarrollo nacional de esta energía.

  5. Single Molecules as Optical Probes for Structure and Dynamics

    Science.gov (United States)

    Orrit, Michel

    Single molecules and single nanoparticles are convenient links between the nanoscale world and the laboratory. We discuss the limits for their optical detection by three different methods: fluorescence, direct absorption, and photothermal detection. We briefly review some recent illustrations of qualitatively new information gathered from single-molecule signals: intermittency of the fluorescence intensity, acoustic vibrations of nanoparticles (1-100 GHz) or of extended defects in molecular crystals (0.1-1 MHz), and dynamical heterogeneity in glass-forming molecular liquids. We conclude with an outlook of future uses of single-molecule methods in physical chemistry, soft matter, and material science.

  6. Thermo-dynamical contours of electronic-vibrational spectra simulated using the statistical quantum-mechanical methods

    DEFF Research Database (Denmark)

    Pomogaev, Vladimir; Pomogaeva, Anna; Avramov, Pavel

    2011-01-01

    Three polycyclic organic molecules in various solvents focused on thermo-dynamical aspects were theoretically investigated using the recently developed statistical quantum mechanical/classical molecular dynamics method for simulating electronic-vibrational spectra. The absorption bands of estradiol...

  7. A new potential energy surface for vibration-vibration coupling in HF-HF collisions. Formulation and quantal scattering calculations

    Science.gov (United States)

    Schwenke, David W.; Truhlar, Donald G.

    1988-04-01

    We present new ab initio calculations of the HF-HF interaction potential for the case where both molecules are simultaneously displaced from their equilibrium internuclear distance. These and previous ab initio calculations are then fit to a new analytic representation which is designed to be efficient to evaluate and to provide an especially faithful account of the forces along the vibrational coordinates. We use the new potential for two sets of quantal scattering calculations for collisions in three dimensions with total angular momentum zero. First we test that the angular harmonic representation of the anisotropy is adequate by comparing quantal rigid rotator calculations to those carried out for potentials involving higher angular harmonics and for which the expansion in angular harmonics is systematically increased to convergence. Then we carry out large-scale quantal calculations of vibration-vibration energy transfer including the coupling of both sets of vibrational and rotational coordinates. These calculations indicate that significant rotational energy transfer accompanies the vibration-to-vibration energy transfer process.

  8. Vibrational Spectroscopy of the CCl[subscript 4] v[subscript 1] Mode: Theoretical Prediction of Isotopic Effects

    Science.gov (United States)

    Gaynor, James D.; Wetterer, Anna M.; Cochran, Rea M.; Valente, Edward J.; Mayer, Steven G.

    2015-01-01

    Raman spectroscopy is a powerful experimental technique, yet it is often missing from the undergraduate physical chemistry laboratory curriculum. Tetrachloromethane (CCl[subscript 4]) is the ideal molecule for an introductory vibrational spectroscopy experiment and the symmetric stretch vibration contains fine structure due to isotopic variations…

  9. Vibration of fuel bundles

    International Nuclear Information System (INIS)

    Chen, S.S.

    1975-06-01

    Several mathematical models have been proposed for calculating fuel rod responses in axial flows based on a single rod consideration. The spacing between fuel rods in liquid metal fast breeder reactors is small; hence fuel rods will interact with one another due to fluid coupling. The objective of this paper is to study the coupled vibration of fuel bundles. To account for the fluid coupling, a computer code, AMASS, is developed to calculate added mass coefficients for a group of circular cylinders based on the potential flow theory. The equations of motion for rod bundles are then derived including hydrodynamic forces, drag forces, fluid pressure, gravity effect, axial tension, and damping. Based on the equations, a method of analysis is presented to study the free and forced vibrations of rod bundles. Finally, the method is applied to a typical LMFBR fuel bundle consisting of seven rods

  10. Cuantificación del potencial energético undimotriz en las costas del Caribe colombiano

    Directory of Open Access Journals (Sweden)

    Jaime P

    2017-11-01

    Full Text Available En este documento se describen los avances en la cuantificación de la energía de las olas de la costa caribeña colombiana. La metodología utilizada servirá como punto de partida para establecer el potencial energético en Colombia para este tipo de suministro energético. En la actualidad, el potencial energético teórico estimado en las ondas de la costa cercana en la costa atlántica es de aproximadamente 1107 MW y esto fue posible con datos que se han recogido y procesado desde enero de 2014. Las ecuaciones que tienen en cuenta variables tales como: la densidad del agua de mar, la temperatura y la velocidad del viento en la zona. También muestra el progreso del diseño del sistema Near Shore para la verificación del potencial de energía de las olas que consiste en un dispositivo que transforma la energía cinética de las ondas del mar en energía potencial gravitacional que se va a usar para mover un generador de corriente alterna.

  11. The influence of molecular rotation on vibration--translation energy transfer

    International Nuclear Information System (INIS)

    McKenzie, R.L.

    1977-01-01

    The role of molecular rotations in the exchange of vibrational and translational energy is investigated for collisions between anharmonic diatomic molecules and structureless atoms. A three-dimensional, semiclassical, impact parameter description is applied with emphasis directed towards the influence of rotational coupling on the net rate of vibrational energy transfer summed over all final rotational states. These results are then related to the predictions of an equivalent collinear collision model, and their comparison allows an evaluation of the collinear approximation. The mechanisms of vibrational energy transfer including rotational transitions are shown to be separable into three classes, with the molecules belonging to each class identified first and foremost by their ratio of fundamental vibrational and rotational frequencies, ω/sub e//B/sub e/, and second by the proximity of their initial state to a near-resonant vibration--rotation transition with a small change in angular momentum. While the dynamics of molecules with ω/sub e//B/sub e/ ratios that are comparable to the range of angular momentum transitions having strong coupling are found to require a complete three-dimensional description, the rates of vibrational energy transfer in molecules with large ω/sub e//B/sub e/ ratios appear to be well approximated by a collinear collision model

  12. Pickin’ up good vibrations

    CERN Multimedia

    Katarina Anthony

    2015-01-01

    In preparation for the civil engineering work on the HL-LHC, vibration measurements were carried out at the LHC’s Point 1 last month. These measurements will help evaluate how civil engineering work could impact the beam, and will provide crucial details about the site’s geological make-up before construction begins.   A seismic truck at Point 1 generated wave-like vibrations measured by EN/MME. From carrying out R&D to produce state-of-the-art magnets to developing innovative, robust materials capable of withstanding beam impact, the HL-LHC is a multi-faceted project involving many groups and teams across CERN’s departments. It was in this framework that the project management mandated CERN's Mechanical and Materials Engineering (EN/MME) group to measure the propagation of vibrations around Point 1. Their question: can civil engineering work for the HL-LHC – the bulk of which is scheduled for LS2 – begin while the LHC is running? Alth...

  13. Vibrational stability of graphene

    Directory of Open Access Journals (Sweden)

    Yangfan Hu

    2013-05-01

    Full Text Available The mechanical stability of graphene as temperature rises is analyzed based on three different self-consistent phonon (SCP models. Compared with three-dimensional (3-D materials, the critical temperature Ti at which instability occurs for graphene is much closer to its melting temperature Tm obtained from Monte Carlo simulation (Ti ≃ 2Tm, K. V. Zakharchenko, A. Fasolino, J. H. Los, and M. I. Katsnelson, J. Phys. Condens. Matter 23, 202202. This suggests that thermal vibration plays a significant role in melting of graphene while melting for 3-D materials is often dominated by topologic defects. This peculiar property of graphene derives from its high structural anisotropy, which is characterized by the vibrational anisotropic coefficient (VAC, defined upon its Lindermann ratios in different directions. For any carbon based material with a graphene-like structure, the VAC value must be smaller than 5.4 to maintain its stability. It is also found that the high VAC value of graphene is responsible for its negative thermal expansion coefficient at low temperature range. We believe that the VAC can be regarded as a new criterion concerning the vibrational stability of any low-dimensional (low-D materials.

  14. An experimental and theoretical study of molecular structure and vibrational spectra of 2-methylphenyl boronic acid by density functional theory calculations

    Science.gov (United States)

    Hiremath, Sudhir M.; Hiremath, C. S.; Khemalapure, S. S.; Patil, N. R.

    2018-05-01

    This paper reports the experimental and theoretical study on the structure and vibrations of 2-Methylphenyl boronic acid (2MPBA). The different spectroscopic techniques such as FT-IR (4000-400 cm-1) and FT-Raman (4000-50 cm-1) of the title molecule in the solid phase were recorded. The geometry of the molecule was fully optimized using density functional theory (DFT) (B3LYP) with 6-311++G(d, p) basis set calculations. The vibrational wavenumbers were also corrected with scale factor to take better results for the calculated data. Vibrational spectra were calculated and fundamental vibrations were assigned on the basis of the potential energy distribution (PED) of the vibrational modes obtained from VEDA 4 program. The calculated wavenumbers showed the best agreement with the experimental results. Whereas, it is observed that, the theoretical frequencies are more than the experimental one for O-H stretching vibration modes of the title molecule.

  15. Thermally induced charge current through long molecules

    Science.gov (United States)

    Zimbovskaya, Natalya A.; Nitzan, Abraham

    2018-01-01

    In this work, we theoretically study steady state thermoelectric transport through a single-molecule junction with a long chain-like bridge. Electron transmission through the system is computed using a tight-binding model for the bridge. We analyze dependences of thermocurrent on the bridge length in unbiased and biased systems operating within and beyond the linear response regime. It is shown that the length-dependent thermocurrent is controlled by the lineshape of electron transmission in the interval corresponding to the HOMO/LUMO transport channel. Also, it is demonstrated that electron interactions with molecular vibrations may significantly affect the length-dependent thermocurrent.

  16. La utilización eficaz del hormigón térmico en rehabilitación energética de edifcios

    OpenAIRE

    Moraño Rodríguez, Alfonso Javier

    2016-01-01

    Como sabrá el lector, se ha establecido en España por consecuencia de la Directiva 2012/27/ UE, un Programa de Ayudas para la Rehabilitación Energética de Edificios existentes (Programa PAREER-CRECE) con el fin de incentivar y promover la realización de actuaciones de reforma que favorezcan el ahorro energético, la mejora de la eficiencia energética, el aprovechamiento de las energías renovables y la reducción de emisiones de dióxido de carbono. El Ministerio de Industria, Energía y Turismo, ...

  17. Proyecto de vivienda energéticamente sostenible situada en Ontinyent (Valencia). Instalación fotovoltaica.

    OpenAIRE

    MOLLÁ CALABUIG, SERGIO

    2015-01-01

    [ES] Se van a diseñar las instalaciones necesarias para que una vivienda unifamiliar sea energéticamente sostenible. La única fuente de energía disponible es la solar Se calcualrán las instalaciones para dos opciones. 1. Vivienda conectada a la red eléctrica general. 2. Vivienda aislada de la red eléctrica. [ES] El objeto de este trabajo es el diseño y comparación, de las instalaciones necesarias para que una vivienda unifamiliar sea energéticamente sostenible, con la única fuen...

  18. Proyecto de vivienda energéticamente sostenible situada en Almería. Instalación fotovoltaica.

    OpenAIRE

    CORBERÁ FERRANDO, JOSÉ Mª

    2015-01-01

    [ES] Se van a diseñar las instalaciones necesarias para que una vivienda unifamiliar sea energéticamente sostenible. La única fuente de energía disponible es la solar Se calcualrán las instalaciones para dos opciones. 1. Vivienda conectada a la red eléctrica general. 2. Vivienda aislada de la red eléctrica. Corberá Ferrando, JM. (2015). Proyecto de vivienda energéticamente sostenible situada en Almería. Instalación fotovoltaica. http://hdl.handle.net/10251/53541. TFGM

  19. Planeamiento estratégico del sector de las fuentes no convencionales de energía renovable en Colombia

    OpenAIRE

    Torres Wilches, Carlos Rolando; Rojas Patiño, Alejandro; Higuera Rincón, Diana Astrid; Hernández Henríquez, Jorge Daniel; Calle Forero, Jorge Alberto

    2017-01-01

    xiv, 192 h. : il. ; 30 cm. A través de los años y en el ámbito mundial, la generación de energía eléctrica por medio de fuentes no convencionales de energía como el sol, el viento, la biomasa, y la energía mareomotriz, ha estado creciendo constantemente tanto en capacidad instalada (i.e., megawatt) como en número de proyectos implementados. Parte importante de este crecimiento se debe a la mejora continua en la tecnología de producción que utilizan entre otros los paneles so...

  20. Liga de magnésio como material para bateria de alta densidade energética

    OpenAIRE

    Munhoz, Igor Polezi

    2014-01-01

    Orientador: Prof. Dr. Jorge Tomioka Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2014. No contexto energético, as mudanças climáticas e as crescentes crises energéticas aumentaram as preocupações e as pesquisas na área de acumuladores de energia, visando alcançar melhorias no cenário energético e ambiental global. Ao mesmo tempo, a sociedade tornou-se dependente do consumo de energia elétrica, sendo que falhas no fornec...

  1. Estimación del potencial de energías renovables en el estado de Sonora

    OpenAIRE

    Jorge Luis Taddei Bringas; María de los Ángeles Navarrete Hinojosa; Pablo Daniel Taddei Arriola; Rafael Cabanillas López.

    2016-01-01

    La etapa de uso de combustibles fósiles está llegando a su fin, debido principalmente a la escasez y problemas de contaminación que originan. En la actualidad existe una marcada tendencia en aprovechar las fuentes renovables de energía, por su bajo impacto ambiental y menor emisión de gases de efecto invernadero (GEI), lo cual contribuye a independizar las políticas energéticas locales de las del mercado global, basadas en la supremacía petrolera. Para obtener el mayor provecho de las energía...

  2. Consistent quantum approach to new laser-electron-nuclear effects in diatomic molecules

    International Nuclear Information System (INIS)

    Glushkov, A V; Malinovskaya, S V; Loboda, A V; Shpinareva, I M; Prepelitsa, G P

    2006-01-01

    We present a consistent, quantum approach to the calculation of electron-nuclear γ. spectra (set of vibrational and rotational satellites) for nuclei in diatomic molecules. The approach generelizes the well known Letokhov-Minogin model and is based on the Dunham model potential approximation for potential curves of diatomic molecules. The method is applied to the calculation of probabilities of the vibration-rotation-nuclear transitions in a case of emission and absorption spectrum for the nucleus 127 I (E γ (0) = 203 keV) linked with the molecule H 127 I

  3. Formation of Ultracold Molecules

    Energy Technology Data Exchange (ETDEWEB)

    Cote, Robin [Univ. of Connecticut, Storrs, CT (United States)

    2016-01-28

    Advances in our ability to slow down and cool atoms and molecules to ultracold temperatures have paved the way to a revolution in basic research on molecules. Ultracold molecules are sensitive of very weak interactions, even when separated by large distances, which allow studies of the effect of those interactions on the behavior of molecules. In this program, we have explored ways to form ultracold molecules starting from pairs of atoms that have already reached the ultracold regime. We devised methods that enhance the efficiency of ultracold molecule production, for example by tuning external magnetic fields and using appropriate laser excitations. We also investigates the properties of those ultracold molecules, especially their de-excitation into stable molecules. We studied the possibility of creating new classes of ultra-long range molecules, named macrodimers, thousand times more extended than regular molecules. Again, such objects are possible because ultra low temperatures prevent their breakup by collision. Finally, we carried out calculations on how chemical reactions are affected and modified at ultracold temperatures. Normally, reactions become less effective as the temperature decreases, but at ultracold temperatures, they can become very effective. We studied this counter-intuitive behavior for benchmark chemical reactions involving molecular hydrogen.

  4. Deviations from the Boltzmann distribution in vibrationally excited gas flows

    International Nuclear Information System (INIS)

    Offenhaeuser, F.; Frohn, A.

    1986-01-01

    A new model for the exchange of vibrational energy in one-dimensional flows of CO 2 -H 2 O-N 2 -O 2 -He gas mixtures is presented. In contrast to previous models, the assumption of local Boltzmann distributions for the vibrational degrees of freedom is not required. This generalization was achieved by the assumption that the molecules are harmonic oscillators with one or more degrees of freedom represented by finite numbers of energy levels. The population densities of these energy levels are coupled by a set of rate equations. It is shown that in some cases of molecular gas flow the Boltzmann distribution for the vibrational degrees of freedom may be disturbed. 12 references

  5. On selection rules in vibrational and rotational molecular spectroscopy

    International Nuclear Information System (INIS)

    Guichardet, A.

    1986-01-01

    The aim of this work is a rigorous proof of the Selection Rules in Molecular Spectroscopy (Vibration and Rotation). To get this we give mathematically rigorous definitions of the (tensor) transition operators, in this case the electric dipole moment; this is done, firstly by considering the molecule as a set of point atomic kernels performing arbitrary motions, secondly by limiting ourselves either to infinitesimal vibration motions, or to arbitrary rotation motions. Then the selection rules follow from an abstract formulation of the Wigner-Eckart theorem. In a last paragraph we discuss the problem of separating vibration and rotation motions; very simple ideas from Differential Geometry, linked with the ''slice theorem'', allow us to define the relative speeds, the solid motions speeds, the Coriolis energies and the moving Eckart frames [fr

  6. Conformational, vibrational, NMR and DFT studies of N-methylacetanilide.

    Science.gov (United States)

    Arjunan, V; Santhanam, R; Rani, T; Rosi, H; Mohan, S

    2013-03-01

    A detailed conformational, vibrational, NMR and DFT studies of N-methylacetanilide have been carried out. In DFT, B3LYP method have been used with 6-31G(**), 6-311++G(**) and cc-pVTZ basis sets. The vibrational frequencies were calculated resulting in IR and Raman frequencies together with intensities and Raman depolarisation ratios. The dipole moment derivatives were computed analytically. Owing to the complexity of the molecule, the potential energy distributions of the vibrational modes of the compound are also calculated. Isoelectronic molecular electrostatic potential surface (MEP) and electron density surface were examined. (1)H and (13)C NMR isotropic chemical shifts were calculated and the assignments made are compared with the experimental values. The energies of important MO's of the compound were also determined from TD-DFT method. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Random vibrations theory and practice

    CERN Document Server

    Wirsching, Paul H; Ortiz, Keith

    1995-01-01

    Random Vibrations: Theory and Practice covers the theory and analysis of mechanical and structural systems undergoing random oscillations due to any number of phenomena— from engine noise, turbulent flow, and acoustic noise to wind, ocean waves, earthquakes, and rough pavement. For systems operating in such environments, a random vibration analysis is essential to the safety and reliability of the system. By far the most comprehensive text available on random vibrations, Random Vibrations: Theory and Practice is designed for readers who are new to the subject as well as those who are familiar with the fundamentals and wish to study a particular topic or use the text as an authoritative reference. It is divided into three major sections: fundamental background, random vibration development and applications to design, and random signal analysis. Introductory chapters cover topics in probability, statistics, and random processes that prepare the reader for the development of the theory of random vibrations a...

  8. VIBRATION ISOLATION SYSTEM PROBABILITY ANALYSIS

    Directory of Open Access Journals (Sweden)

    Smirnov Vladimir Alexandrovich

    2012-10-01

    Full Text Available The article deals with the probability analysis for a vibration isolation system of high-precision equipment, which is extremely sensitive to low-frequency oscillations even of submicron amplitude. The external sources of low-frequency vibrations may include the natural city background or internal low-frequency sources inside buildings (pedestrian activity, HVAC. Taking Gauss distribution into account, the author estimates the probability of the relative displacement of the isolated mass being still lower than the vibration criteria. This problem is being solved in the three dimensional space, evolved by the system parameters, including damping and natural frequency. According to this probability distribution, the chance of exceeding the vibration criteria for a vibration isolation system is evaluated. Optimal system parameters - damping and natural frequency - are being developed, thus the possibility of exceeding vibration criteria VC-E and VC-D is assumed to be less than 0.04.

  9. Augmented-plane-wave calculations on small molecules

    International Nuclear Information System (INIS)

    Serena, P.A.; Baratoff, A.; Soler, J.M.

    1993-01-01

    We have performed ab initio calculations on a wide range of small molecules, demonstrating the accuracy and flexibility of an alternative method for calculating the electronic structure of molecules, solids, and surfaces. It is based on the local-density approximation (LDA) for exchange and correlation and the nonlinear augmented-plane-wave method. Very accurate atomic forces are obtained directly. This allows for implementation of Car-Parrinello-like techniques to determine simultaneously the self-consistent electron wave functions and the equilibrium atomic positions within an iterative scheme. We find excellent agreement with the best existing LDA-based calculations and remarkable agreement with experiment for the equilibrium geometries, vibrational frequencies, and dipole moments of a wide variety of molecules, including strongly bound homopolar and polar molecules, hydrogen-bound and electron-deficient molecules, and weakly bound alkali and noble-metal dimers, although binding energies are overestimated

  10. Vibration damping method and apparatus

    Science.gov (United States)

    Redmond, James M.; Barney, Patrick S.; Parker, Gordon G.; Smith, David A.

    1999-01-01

    The present invention provides vibration damping method and apparatus that can damp vibration in more than one direction without requiring disassembly, that can accommodate varying tool dimensions without requiring re-tuning, and that does not interfere with tool tip operations and cooling. The present invention provides active dampening by generating bending moments internal to a structure such as a boring bar to dampen vibration thereof.

  11. Atomic beams probe surface vibrations

    International Nuclear Information System (INIS)

    Robinson, A.L.

    1982-01-01

    In the last two years, surface scientist have begun trying to obtain the vibrational frequencies of surface atoms in both insulating and metallic crystals from beams of helium atoms. It is the inelastic scattering that researchers use to probe surface vibrations. Inelastic atomic beam scattering has only been used to obtain vibrational frequency spectra from clean surfaces. Several experiments using helium beams are cited. (SC)

  12. The status of molecules

    International Nuclear Information System (INIS)

    Barnes, T.; Oak Ridge National Lab., TN; Tennessee Univ., Knoxville, TN

    1994-06-01

    This report summarizes the experimental and theoretical status of hadronic molecules, which are weakly-bound states of two or more hadrons. We begin with a brief history of the subject and discuss a few good candidates, and then abstract some signatures for molecules which may be of interest in the classification of possible molecule states. Next we argue that a more general understanding of 2 → 2 hadron-hadron scattering amplitudes will be crucial for molecule searches, and discuss some of our recent work in this area. We conclude with a discussion of a few more recent molecule candidates (notably the f o (1710)) which are not well established as molecules but satisfy some of the expected signatures. (Author)

  13. Hydrogen molecules and hydrogen-related defects in crystalline silicon

    OpenAIRE

    Fukata, N.; Sasak, S.; Murakami, K.; Ishioka, K.; Nakamura, K. G.; Kitajima, M.; Fujimura, S.; Kikuchi, J.; Haneda, H.

    1997-01-01

    We have found that hydrogen exists in molecular form in crystalline silicon treated with hydrogen atoms in the downstream of a hydrogen plasma. The vibrational Raman line of hydrogen molecules is observed at 4158cm-1 for silicon samples hydrogenated between 180 and 500 °C. The assignment of the Raman line is confirmed by its isotope shift to 2990cm-1 for silicon treated with deuterium atoms. The Raman intensity has a maximum for hydrogenation at 400 °C. The vibrational Raman line of the hydro...

  14. Time-resolved spectroscopy defines perturbation in molecules

    International Nuclear Information System (INIS)

    Ahmed, K.

    1998-01-01

    Time-resolved LIF spectroscopy is employed in order to investigate perturbations in different excited electronic state of alkali molecules. Dunham Coefficients are used to search the selected excited ro-vibrational level, which is overlap with the other nearby excited states. Lifetime measurement has been performed of more than 50 ro-vibrational levels. Out of these 25 levels were observed drastically different lifetimes from the other unperturbed levels. In this report, influence of different perturbations on this anomalous behavior is investigated and discussed. (author)

  15. Advances in molecular vibrations and collision dynamics molecular clusters

    CERN Document Server

    Bacic, Zatko

    1998-01-01

    This volume focuses on molecular clusters, bound by van der Waals interactions and hydrogen bonds. Twelve chapters review a wide range of recent theoretical and experimental advances in the areas of cluster vibrations, spectroscopy, and reaction dynamics. The authors are leading experts, who have made significant contributions to these topics.The first chapter describes exciting results and new insights in the solvent effects on the short-time photo fragmentation dynamics of small molecules, obtained by combining heteroclusters with femtosecond laser excitation. The second is on theoretical work on effects of single solvent (argon) atom on the photodissociation dynamics of the solute H2O molecule. The next two chapters cover experimental and theoretical aspects of the energetics and vibrations of small clusters. Chapter 5 describes diffusion quantum Monte Carlo calculations and non additive three-body potential terms in molecular clusters. The next six chapters deal with hydrogen-bonded clusters, refle...

  16. Vibrational excitations in molecular layers probed by ballistic electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Kajen, Rasanayagam Sivasayan; Chandrasekhar, Natarajan [Institute of Materials Research and Engineering, 3 Research Link, 117602 (Singapore); Feng Xinliang; Muellen, Klaus [Max-Planck-Institut fuer Polymerforschung, Postfach 3148, D-55021 Mainz (Germany); Su Haibin, E-mail: n-chandra@imre.a-star.edu.sg, E-mail: muellen@mpip-mainz.mpg.de, E-mail: hbsu@ntu.edu.sg [Division of Materials Science, Nanyang Technological University, 50 Nanyang Avenue, 639798 (Singapore)

    2011-10-28

    We demonstrate the information on molecular vibrational modes via the second derivative (d{sup 2}I{sub B}/dV{sup 2}) of the ballistic electron emission spectroscopy (BEES) current. The proposed method does not create huge fields as in the case of conventional derivative spectroscopy and maintains a zero bias across the device. BEES studies carried out on three different types of large polycyclic aromatic hydrocarbon (PAH) molecular layers show that the d{sup 2}I{sub B}/dV{sup 2} spectra consist of uniformly spaced peaks corresponding to vibronic excitations. The peak spacing is found to be identical for molecules within the same PAH family though the BEES onset voltage varies for different molecules. In addition, injection into a particular orbital appears to correspond to a specific vibrational mode as the manifestation of the symmetry principle.

  17. Experimental and computational study on molecular structure and vibrational analysis of an antihyperglycemic biomolecule: Gliclazide

    Science.gov (United States)

    Karakaya, Mustafa; Kürekçi, Mehmet; Eskiyurt, Buse; Sert, Yusuf; Çırak, Çağrı

    2015-01-01

    In present study, the experimental and theoretical harmonic vibrational frequencies of gliclazide molecule have been investigated. The experimental FT-IR (400-4000 cm-1) and Laser-Raman spectra (100-4000 cm-1) of the molecule in the solid phase were recorded. Theoretical vibrational frequencies and geometric parameters (bond lengths and bond angles) have been calculated using ab initio Hartree Fock (HF), density functional theory (B3LYP hybrid function) methods with 6-311++G(d,p) and 6-31G(d,p) basis sets by Gaussian 09W program. The assignments of the vibrational frequencies were performed by potential energy distribution (PED) analysis by using VEDA 4 program. Theoretical optimized geometric parameters and vibrational frequencies have been compared with the corresponding experimental data, and they have been shown to be in a good agreement with each other. Also, the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies have been found.

  18. Cold Rydberg molecules

    Science.gov (United States)

    Raithel, Georg; Zhao, Jianming

    2017-04-01

    Cold atomic systems have opened new frontiers at the interface of atomic and molecular physics. These include research on novel types of Rydberg molecules. Three types of molecules will be reviewed. Long-range, homonuclear Rydberg molecules, first predicted in [1] and observed in [2], are formed via low-energy electron scattering of the Rydberg electron from a ground-state atom within the Rydberg atom's volume. The binding mostly arises from S- and P-wave triplet scattering. We use a Fermi model that includes S-wave and P-wave singlet and triplet scattering, the fine structure coupling of the Rydberg atom and the hyperfine structure coupling of the 5S1/2 atom (in rubidium [3]). The hyperfine structure gives rise to mixed singlet-triplet potentials for both low-L and high-L Rydberg molecules [3]. A classification into Hund's cases [3, 4, 5] will be discussed. The talk further includes results on adiabatic potentials and adiabatic states of Rydberg-Rydberg molecules in Rb and Cs. These molecules, which have even larger bonding length than Rydberg-ground molecules, are formed via electrostatic multipole interactions. The leading interaction term of neutral Rydberg-Rydberg molecules is between two dipoles, while for ionic Rydberg molecules it is between a dipole and a monopole. NSF (PHY-1506093), NNSF of China (61475123).

  19. Mechanism of Occurring Over-Voltage Phenomena in Distributed Power System on Energization of Transformers

    Science.gov (United States)

    Nakachi, Yoshiki; Ueda, Fukashi; Kajikawa, Takuya; Amau, Tooru; Kameyama, Hirokazu; Ito, Hisanori

    This paper verifies the mechanism of occurring over voltage phenomena in the distributed power system on energizing the transformer. This over-voltage, which is observed at the actual distributed power system, with heavy inrush current is found to occur at about 0.1-0.2sec after the energizing and continue for a duration of more than 0.1[sec]. There is a concern that this over-voltage may operate the protection relay and deteriorate the insulation of apparatus. It is basically caused by the resonance between the shunt capacitors and saturated/unsaturated magnetizing inductance of transformer, system inductance. By using analytical formulation of a simple equivalent circuit, its mechanism has been verified through simulations carried out by using EMTP. Moreover, the sympathetic interaction between transformers is prolonged the duration of the over-voltage by the field test data is discussed in this paper.

  20. Integración energética: una incertidumbre regulatoria

    Directory of Open Access Journals (Sweden)

    María de la Cruz Bayá C.

    2006-01-01

    Full Text Available Este artículo pretende introducir en la reflexión de los elementos que están insertos hoy por hoy en la agenda de la integración energética, como uno de los baluartes más importantes para la consolidación de los procesos subregionales ya que establece, per se, la base de la nueva configuración de las relaciones interestatales a partir de la relación de oferta y demanda energética. En este sentido, los métodos utilizados en la presente investigación han sido el exegético, comparado, estudio de caso y bibliográfico, lo cual ha permitido concluir que se requiere de la generación de un marco regulatorio comunitario armonizado, vinculado a los principios de supranacionalidad y de sustentabilidad.

  1. Design and Implementation of Energized Fracture Treatment in Tight Gas Sands

    Energy Technology Data Exchange (ETDEWEB)

    Mukul Sharma; Kyle Friehauf

    2009-12-31

    Hydraulic fracturing is essential for producing gas and oil at an economic rate from low permeability sands. Most fracturing treatments use water and polymers with a gelling agent as a fracturing fluid. The water is held in the small pore spaces by capillary pressure and is not recovered when drawdown pressures are low. The un-recovered water leaves a water saturated zone around the fracture face that stops the flow of gas into the fracture. This is a particularly acute problem in low permeability formations where capillary pressures are high. Depletion (lower reservoir pressures) causes a limitation on the drawdown pressure that can be applied. A hydraulic fracturing process can be energized by the addition of a compressible, sometimes soluble, gas phase into the treatment fluid. When the well is produced, the energized fluid expands and gas comes out of solution. Energizing the fluid creates high gas saturation in the invaded zone, thereby facilitating gas flowback. A new compositional hydraulic fracturing model has been created (EFRAC). This is the first model to include changes in composition, temperature, and phase behavior of the fluid inside the fracture. An equation of state is used to evaluate the phase behavior of the fluid. These compositional effects are coupled with the fluid rheology, proppant transport, and mechanics of fracture growth to create a general model for fracture creation when energized fluids are used. In addition to the fracture propagation model, we have also introduced another new model for hydraulically fractured well productivity. This is the first and only model that takes into account both finite fracture conductivity and damage in the invaded zone in a simple analytical way. EFRAC was successfully used to simulate several fracture treatments in a gas field in South Texas. Based on production estimates, energized fluids may be required when drawdown pressures are smaller than the capillary forces in the formation. For this field

  2. D0 Central Tracking Solenoid Energization, Controls, Interlocks and Quench Protection Initial Validation Procedures

    International Nuclear Information System (INIS)

    Jaskierny, W.; Hance, R.

    1998-01-01

    This note presents the inspection and tests to be performed on the DZERO solenoid energization, controls, interlocks and quench protection system before it is energized for the first time. This test is to be performed with a 5000A jumper at the end of the bus instead of the solenoid. This system is based in DZERO room 511. A copy of this note shall be annotated, signed and dated by the person coordinating the procedure; and filed with the system maintenance records. Annotations shall include comments about any aspect of the procedure that is abnormal or unsuccessful. The following inspections and tests shall be performed by persons knowledgeable about the system. Each individual test step should be reviewed and understood before proceeding with that step.

  3. Programación por metas Energía alternativa mediante biomasa.

    Directory of Open Access Journals (Sweden)

    Guerrero Casas, Flor María

    2003-01-01

    Full Text Available En este trabajo se presenta un modelo multicriterio de localización de centrales de generación de energía eléctrica mediante biomasa. Los objetivos considerados son: (1 minimizar el coste total de la operación, (2 maximizar la producción de electricidad obtenida, (3 maximizar la distancia entre plantas, (4 maximizar la aceptación social y (5 establecer las plantas o ampliaciones en aquellos lugares donde exista una mayor predisposición por parte de las administraciones locales. Finalmente, se concluye con una aplicación práctica mediante programación por metas ponderadas para la región andaluza, considerando los residuos procedentes del olivar como fuente de energía.

  4. Vibrational quasi-continuum in unimolecular multiphoton dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Fernandez, P.; Gonzalez-Diaz, P.F.

    1987-04-01

    The vibrational quasi-continuum of the boron trifluoride molecule has been qualitatively studied and the formalism extended to treat N-normal-mode molecules. The anharmonic potential curves for the BF/sub 3/ normal modes have been calculated, and the computed anharmonicity constants have been tested against the fundamental frequencies. The potential curve of the wagging mode has been simulated by an internal rotation of one of the fluoride atoms. The vibrational-energy levels and wave functions have been calculated applying second-order perturbation theory. The quasi-continuum energy levels of BF/sub 3/ have been obtained by means of a method based in forming adequate linear combinations of wave functions belonging to the N-1 modes resulting from removing the i.r.-active mode;the associated energies have been minimized using a constrained minimization procedure. It has been found that the energy pattern of the N-1 vibrational modes possesses an energy density high enough for constituting a vibrational heat bath and, finally, it has been verified that the ''fictitious'' pattern of the active mode is included in the pattern of the N-1 modes.

  5. Digital analysis of vibrations

    International Nuclear Information System (INIS)

    Bohnstedt, H.J.; Walter, G.

    1982-01-01

    Vibrational measurements, e.g. on turbomachinery, can be evaluated rapidly and economically with the aid of a combination of the following instruments: a desk-top computer, a two-channel vector filter and a FFT spectral analyzer. This equipment combination is available within the Allianz Centre for Technology and has also been used for mobile, on-site investigations during the last year. It enables calculation and display of time functions, kinetic shaft orbits, displacement diagrams. Bode plots, polar-coordinate plots, cascade diagrams and histograms. (orig.) [de

  6. Turbine blade vibration dampening

    Science.gov (United States)

    Cornelius, C.C.; Pytanowski, G.P.; Vendituoli, J.S.

    1997-07-08

    The present turbine wheel assembly increases component life and turbine engine longevity. The combination of the strap and the opening combined with the preestablished area of the outer surface of the opening and the preestablished area of the outer circumferential surface of the strap and the friction between the strap and the opening increases the life and longevity of the turbine wheel assembly. Furthermore, the mass ``M`` or combined mass ``CM`` of the strap or straps and the centrifugal force assist in controlling vibrations and damping characteristics. 5 figs.

  7. Vibration control, machine diagnostics

    International Nuclear Information System (INIS)

    1990-01-01

    Changing vibrations announce damage in the form of wear or cracks on components of, e.g., engine rotors, pumps, power plant turbo sets, rounding-up tools, or marine diesel engines. Therefore, machine diagnostics use frequency analyses, system tests, trend analyses as well as expert systems to localize or estimate the causes of these damages and malfunctions. Data acquisistion, including not only sensors, but also reliable and redundant data processing systems and analyzing systems, play an important role. The lectures pertaining to the data base are covered in detail. (DG) [de

  8. Quantum interference experiments with complex organic molecules

    International Nuclear Information System (INIS)

    Eibenberger, S. I.

    2015-01-01

    Matter-wave interference with complex particles is a thriving field in experimental quantum physics. The quest for testing the quantum superposition principle with highly complex molecules has motivated the development of the Kapitza-Dirac-Talbot-Lau interferometer (KDTLI). This interferometer has enabled quantum interference with large organic molecules in an unprecedented mass regime. In this doctoral thesis I describe quantum superposition experiments which we were able to successfully realize with molecules of masses beyond 10 000 amu and consisting of more than 800 atoms. The typical de Broglie wavelengths of all particles in this thesis are in the order of 0.3-5 pm. This is significantly smaller than any molecular extension (nanometers) or the delocalization length in our interferometer (hundreds of nanometers). Many vibrational and rotational states are populated since the molecules are thermally highly excited (300-1000 K). And yet, high-contrast quantum interference patterns could be observed. The visibility and position of these matter-wave interference patterns is highly sensitive to external perturbations. This sensitivity has opened the path to extensive studies of the influence of internal molecular properties on the coherence of their associated matter waves. In addition, it enables a new approach to quantum-assisted metrology. Quantum interference imprints a high-contrast nano-structured density pattern onto the molecular beam which allows us to resolve tiny shifts and dephasing of the molecular beam. I describe how KDTL interferometry can be used to investigate a number of different molecular properties. We have studied vibrationally-induced conformational changes of floppy molecules and permanent electric dipole moments using matter-wave deflectometry in an external electric field. We have developed a new method for optical absorption spectroscopy which uses the recoil of the molecules upon absorption of individual photons. This allows us to

  9. Algebraic descriptions of nuclear and molecular rotation-vibration spectra

    International Nuclear Information System (INIS)

    Roosmalen, O.S. van.

    1982-01-01

    The application of algebraic models to the description of rotational and vibrational degrees of freedom of nuclei and molecules are discussed. Simple model Hamiltonians are shown to give good agreement with the energy spectra of diatomic molecules and nuclei. Some formal aspects of path integral methods for many-boson systems are treated. The two representations for the quantum mechanical propagator are compared and appear to be identical in leading order in 1/N (N is the number of bosons). Approximations for both are static and dynamic problems are discussed. Applications of mean field techniques are also treated. A description of tri- and tetra-atomic molecules in terms of a U(4)xU(4) and U(4)xU(4)xU(4) group structure is given. Linear molecules appear to correspond with symmetries of O(4) type. S-matrix elements are calculated to test mean field methods, and the results compared with exact calculations. (Auth.)

  10. Costa Rica: Hydroelectric utility Energía Global finances upstream reforestation

    OpenAIRE

    Energía Global (Global Energy S.A.); The National Forest Office; National Fund for Forest Financing (FONAFIFO)

    2006-01-01

    Metadata only record The goal of Energía Global is to increase both the stream flow and decrease sedimentation in the hydroelectric reservoirs. They are attempting to do this by reforestation projects as well as forest conservation. The sources of revenue for this project are from the private hydroelectric company and the government through taxes on fossil fuels. PES-1 (Payments for Environmental Services Associate Award)

  11. Voltage dip caused by the sequential energization of wind turbine transformers

    DEFF Research Database (Denmark)

    Arana Aristi, Iván; Holbøll, Joachim; Sørensen, T.

    2009-01-01

    motors, this recommendation automatically applies to the wind turbine transformers in a wind farm, regardless of the fact that wind turbine transformers are rarely energized and the investment of timed relays might be significant. At the design stage of the collection grid of large offshore wind farms...... farms in Denmark and the UK. However, there is still work to be done to optimize the investment and protection system of the internal grid of the wind power plants....

  12. D0 Central Tracking Solenoid Energization, Controls, Interlocks and Quench Protection Operating Procedures

    International Nuclear Information System (INIS)

    Hance, R.

    1998-01-01

    This procedure is used when it is necessary to operate the solenoid energization, controls, interlocks and quench detection system. Note that a separate procedure exists for operating the solenoid 'cryogenic' systems. Only D0 Control Room Operators or the Project Electrical Engineer are qualified to execute these procedures or operate the solenoid system. This procedure assumes that the operator is familiar with using the Distributed Manufacturing Automation and Control Software (DMACS).

  13. Transformer inrush current reduction through sequential energization for wind farm applications

    Energy Technology Data Exchange (ETDEWEB)

    Abdulsalam, S.; Xu, W. [Alberta Univ., Edmonton, AB (Canada)

    2008-07-01

    Wind power is considered as one of the fastest growing technologies in the power industry. The electrical configuration of a wind farm consists of long spans of medium voltage collector feeders. Each wind generator is connected to the collector circuit/feeder through either a pad mount oil filled, or a nacelle-mounted dry type transformer. All collector feeders connect to a single collector substation where the connection to the high-voltage transmission is established through a step up transformer. With a large number of wind generators per feeder, large inrush current will flow due to simultaneous transformer energization which can cause high voltage sag at the point of common coupling. Wind farms are generally located in unpopulated remote areas where no access to strong network connection is feasible. It is common to have the PCC on a relatively weak location on the sub-transmission/distribution network. In order to meet interconnection standards requirements, the amount of voltage sag due to the energization of a number of transformers needs to be evaluated. This paper presented an effective solution to the mitigation of inrush currents and associated voltage sag for wind farm applications. The paper presented a diagram of a typical configuration of a wind farm electrical distribution system and also described the analytical methodologies for the evaluation of inrush current level together with simulation results. A simplified analysis and sizing criteria for the associated neutral resistor size was presented. It was concluded that the scheme could significantly reduce inrush current level when a large number of transformers are simultaneously energized. The presented application eliminates the need to sectionalize feeders, thereby simplifying them for the energization process. 6 refs., 5 figs.

  14. Investigation of Prevalence of Energizer Drugs and Supplements Consumption and Effective Factors Among Bodybuilder Men in Karaj (2011)

    OpenAIRE

    F. Shoshtarizadeh; F. Bahramian; A.A. Safari; M. Pourghaderi; H. Barati

    2013-01-01

    Background: Body builder athletes’ high attention to form of body can result in high prevalence of nutritional disorders and habit to energizer drugs consumption. With notice to abuse problems of these drugs, this research was carried out to estimate prevalence of energizer drugs and supplements consumption in Karaj body builder men in 2011. Method: In cross-sectional (description- analytical) research 780 Karaj body builder men were selected randomly. Data were collected through interv...

  15. Off-axis Modal Active Vibration Control Of Rotational Vibrations

    NARCIS (Netherlands)

    Babakhani, B.; de Vries, Theodorus J.A.; van Amerongen, J.

    Collocated active vibration control is an effective and robustly stable way of adding damping to the performance limiting vibrations of a plant. Besides the physical parameters of the Active Damping Unit (ADU) containing the collocated actuator and sensor, its location with respect to the

  16. Vibrational spectroscopic and non-linear optical activity studies on nicotinanilide : A DFT approach

    Science.gov (United States)

    Premkumar, S.; Jawahar, A.; Mathavan, T.; Dhas, M. Kumara; Benial, A. Milton Franklin

    2015-06-01

    The molecular structure of nicotinanilide was optimized by the DFT/B3LYP method with cc-pVTZ basis set using Gaussian 09 program. The first order hyperpolarizability of the molecule was calculated, which exhibits the higher nonlinear optical activity. The natural bond orbital analysis confirms the presence of intramolecular charge transfer and the hydrogen bonding interaction, which leads to the higher nonlinear optical activity of the molecule. The Frontier molecular orbitals analysis of the molecule shows that the delocalization of electron density occurs within the molecule. The lower energy gap indicates that the hydrogen bond formation between the charged species. The vibrational frequencies were calculated and assigned on the basis of potential energy distribution calculation using the VEDA 4.0 program and the corresponding vibrational spectra were simulated. Hence, the nicotinanilide molecule can be a good candidate for second-order NLO material.

  17. Estudio regional del potencial de secado con aire natural y energía solar

    Directory of Open Access Journals (Sweden)

    Jorge Domínguez P.

    1983-09-01

    Full Text Available En este artículo se presenta y aplica una metodología de trabajo basada en la técnica de simulación matemática y desarrollada con el fin de realizar estudios sobre el potencial de secado de productos agropecuarios con aire natural y energía solar de regiones tropicales. La metodología se basa en el uso de un programa de computador e Incluye otros elementos metodológicos en relación con el manejo de la información meteorológica, el patrón de operación del ventilador, el uso de energía solar y la interpretación de los resultados con el fin de optimizar el sistema. Se reportan los resultados del estudio del potencial de secado con aire natural y energía solar de Tuluá (Valle y se proporcionan recomendaciones específicas para la implementación de sistemas de secado a bala temperatura en la Reglón.

  18. A statistical study of ion energization at 1700 km in the auroral region

    Directory of Open Access Journals (Sweden)

    M. Hamrin

    2002-12-01

    Full Text Available We present a comprehensive overview of several potentially relevant causes for the oxygen energization in the auroral region. Data from the Freja satellite near 1700 km altitude are used for an unconditional statistical investigation. The data are obtained in the Northern Hemisphere during 21 months in the declining phase of the solar cycle. The importance of various wave types for the ion energization is statistically studied. We also investigate the correlation of ion heating with precipitating protons, accelerated auroral electrons, suprathermal electron bursts, the electron density variations, Kp index and solar illumination of the nearest conjugate ionosphere. We find that sufficiently strong broad-band ELF waves, electromagnetic ion cyclotron waves, and waves around the lower hybrid frequency are foremost associated with the ion heating. However, magnetosonic waves, with a sharp, lower frequency cutoff just below the proton gyrofrequency, are not found to contribute to the ion heating. In the absence of the first three wave emissions, transversely energized ions are rare. These wave types are approximately equally efficient in heating the ions, but we find that the main source for the heating is broadband ELF waves, since they are most common in the auroral region. We have also observed that the conditions for ion heating are more favourable for smaller ratios of the spectral densities SE /SB of the broadband ELF waves at the oxygen gyrofrequency.Key words. Ionosphere (auroral ionosphere; wave propogation Magnetospheric physics (electric fields

  19. The role of fluid compression in energy conversion and particle energization during magnetic reconnection

    Science.gov (United States)

    Li, X.; Guo, F.; Li, G.; Li, H.

    2016-12-01

    Theories of particle transport and acceleration have shown that fluid compression is the leading mechanism for particle acceleration and plasma energization. However, the role of compression in particle acceleration during magnetic reconnection is unclear. We use two approaches to study this issue. First, using fully kinetic simulations, we quantitatively calculate the effect of compression in energy conversion and particle energization during magnetic reconnection for a range of plasma beta and guide field. We show that compression has an important contribution for the energy conversion between the bulk kinetic energy and the internal energy when the guide field is smaller than the reconnecting component. Based on this result, we then study the large-scale reconnection acceleration by solving the Parker's transport equation in a background reconnecting flow provided by MHD simulations. Due to the compression effect, the simulations suggest fast particle acceleration to high energies in the reconnection layer. This study clarifies the nature of particle acceleration in reconnection layer, and may be important to understand particle acceleration and plasma energization during solar flares.

  20. Ion Composition and Energization in the Earth's Inner Magnetosphere and the Effects on Ring Current Buildup

    Science.gov (United States)

    Keika, K.; Kistler, L. M.; Brandt, P. C.

    2014-12-01

    In-situ observations and modeling work have confirmed that singly-charged oxygen ions, O+, which are of Earth's ionospheric origin, are heated/accelerated up to >100 keV in the magnetosphere. The energetic O+ population makes a significant contribution to the plasma pressure in the Earth's inner magnetosphere during magnetic storms, although under quiet conditions H+ dominates the plasma pressure. The pressure enhancements, which we term energization, are caused by adiabatic heating through earthward transport of source population in the plasma sheet, local acceleration in the inner magnetosphere and near-Earth plasma sheet, and enhanced ion supply from the topside ionosphere. The key issues regarding stronger O+ energization than H+ are non-adiabatic local acceleration, responsible for increase in O+ temperature, and more significant O+ supply than H+, responsible for increase in O+ density. Although several acceleration mechanisms and O+ supply processes have been proposed, it remains an open question what mechanism(s)/process(es) play the dominant role in stronger O+ energization. In this paper we summarize important spacecraft observations including those from Van Allen Probes, introduces the proposed mechanisms/processes that generate O+-rich energetic plasma population, and outlines possible scenarios of O+ pressure abundance in the Earth's inner magnetosphere.