Bound-state quark and gluon contributions to structure functions in QCD

International Nuclear Information System (INIS)

Brodsky, S.J.

1991-01-01

One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: 'intrinsic' contributions, which are due to the direct scattering on the bound-state constituents, and 'extrinsic' contributions, which are derived from particles created in the collision. In this talk, I discuss several aspects of deep inealstic structure functions in which the bound-state structure of the proton plays a crucial role: (1) the properties of the intrinsic gluon distribution associated with the proton bound-state wavefunction; (2) the separation of the quark structure function of the proton into intrinsic 'bound-valence' and extrinsic 'non-valence' components which takes into account the Pauli principle; (3) the properties and identification of intrinsic heavy quark structure functions; and (4) a theory of shadowing and anti-shadowing of nuclear structure functions, directly related to quark-nucleon interactions and the gluon saturation phenomenon. (orig.)

Bound-state quark and gluon contributions to structure functions in QCD

International Nuclear Information System (INIS)

Brodsky, S.J.

1990-08-01

One can distinguish two types of contributions to the quark and gluon structure functions of hadrons in quantum chromodynamics: ''intrinsic'' contributions, which are due to the direct scattering on the bound-state constituents, and ''extrinsic'' contributions, which are derived from particles created in the collision. In this talk, I discussed several aspects of deep inelastic structure functions in which the bound-state structure of the proton plays a crucial role: the properties of the intrinsic gluon distribution associated with the proton bound-state wavefunction; the separation of the quark structure function of the proton onto intrinsic ''bound-valence'' and extrinsic ''non-valence'' components which takes into account the Pauli principle; the properties and identification of intrinsic heavy quark structure functions; and a theory of shadowing and anti-shadowing of nuclear structure functions, directly related to quark-nucleon interactions and the gluon saturation phenomenon. 49 refs., 5 figs

Studies on the valence electronic structure of Fe and Ni in FexNi1−x ...

Indian Academy of Sciences (India)

structure of Fe and Ni in various Fex Ni1−x alloys. Since Kβ-to-Kα X-ray intensity ratio has been reported [2–7] to be a sensitive physical parameter to investigate the changes in the valence electronic structure of 3d-transition metals [2], we have undertaken the study of the valence electronic structure of Fe and Ni in the Fex ...

Valence electronic properties of porphyrin derivatives.

Science.gov (United States)

Stenuit, G; Castellarin-Cudia, C; Plekan, O; Feyer, V; Prince, K C; Goldoni, A; Umari, P

2010-09-28

We present a combined experimental and theoretical investigation of the valence electronic structure of porphyrin-derived molecules. The valence photoemission spectra of the free-base tetraphenylporphyrin and of the octaethylporphyrin molecule were measured using synchrotron radiation and compared with theoretical spectra calculated using the GW method and the density-functional method within the generalized gradient approximation. Only the GW results could reproduce the experimental data. We found that the contribution to the orbital energies due to electronic correlations has the same linear behavior in both molecules, with larger deviations in the vicinity of the HOMO level. This shows the importance of adequate treatment of electronic correlations in these organic systems.

16O + 16O + valence neutrons in molecular orbitals structures of positive- and negative-parity superdeformed bands in 34S

International Nuclear Information System (INIS)

Taniguchi, Yasutaka

2015-01-01

The structures of superdeformed (SD) states in 34 S have been investigated using the antisymmetrized molecular dynamics and generator coordinate method (GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of two positive- and one negative-parity SD bands are predicted, and low-lying states and other deformed bands are obtained. The SD bands have structures of 16 O + 16 O + two valence neutrons in molecular orbitals around the two 16 O cores in a cluster picture. The configurations of the two valence neutrons are δ 2 and π 2 for the positive-parity SD bands and π 1 δ 1 for the negative-parity SD band. (author)

16O + 16O + valence neutrons in molecular orbitals structures of positive- and negative-parity superdeformed bands in 34S

International Nuclear Information System (INIS)

Taniguchi, Yasutaka

2014-01-01

The structures of superdeformed (SD) states in 34 S are investigated using the antisymmetrized molecular dynamics and generator coordinate method (GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of two positive- and one negative-parity SD bands are predicted, and low-lying states and other deformed bands are obtained. The SD bands have structures of 16 O + 16 O + two valence neutrons in molecular orbitals around the two 16 O cores in a cluster picture. The configurations of the two valence neutrons are δ 2 and π 2 for the positive-parity SD bands and π 1 δ 1 for the negative-parity SD band

Valence band structure of PDMS surface and a blend with MWCNTs: A UPS and MIES study of an insulating polymer

Energy Technology Data Exchange (ETDEWEB)

Schmerl, Natalya M.; Khodakov, Dmitriy A.; Stapleton, Andrew J.; Ellis, Amanda V.; Andersson, Gunther G., E-mail: gunther.andersson@flinders.edu.au

2015-10-30

Graphical abstract: - Highlights: • Valence electron spectroscopy was performed on an insulating polymer using different charge compensation methods. • MWCNT were embedded in PDMS and found to be the most effective method for reducing the charging of the insulating polymer. • The valence band spectrum of PDMS was obtained via MIES and UPS. • Ion scattering spectroscopy was used to determine the concentration depth profile of the PDMS in the sample. - Abstract: The use of polydimethylsiloxane (PDMS) is increasing with new technologies working toward compact, flexible and transparent devices for use in medical and microfluidic systems. Electronic characterization of PDMS and other insulating materials is difficult due to charging, yet necessary for many applications where the interfacial structure is vital to device function or further modification. The outermost layer in particular is of importance as this is the area where chemical reactions such as surface functionalization will occur. Here, we investigate the valence band structure of the outermost layer and near surface area of PDMS through the use of metastable induced photoelectron spectroscopy (MIES) paired with ultraviolet photoelectron spectroscopy (UPS). The chemical composition of the samples under investigation were measured via X-ray photoelectron spectroscopy (XPS), and the vertical distribution of the polymer was shown with neutral impact collision ion scattering spectroscopy (NICISS). Three separate methods for charge compensation are used for the samples, and their effectiveness is compared.

Pressure-induced valence and structure change in some anti-Th3P4 structure rare earth compounds

International Nuclear Information System (INIS)

Werner, A.; Hochheimer, H.D.; Jayaraman, A.; Bucher, E.

1981-01-01

The anti-Th 3 P 4 structure compounds Yb 4 Bi 3 and Yb 4 Sb 3 have been investigated to 350 kbar by high pressure X-ray diffraction, using the diamond anvil cell. From the P-V data it is found that Yb 4 Bi 3 and Yb 4 Sb 3 are much more compressible, compared to Sm 4 Bi 3 before the valence transition. This suggests that a continuous change in the valence state of Yb takes place with pressure in the two compounds and that they may be in the mixed valent state already at ambient pressure. The ''collapsed'' anti-Th 3 P 4 structure becomes unstable in Yb 4 Bi 3 and Yb 4 Sb 3 and new lines appear at high pressure, that fit the NaCl structure. The latter structure change seems to occur also in the electronically collapsed Sm 4 Bi 3 . The results are presented and discussed. (Auth.)

Ferromagnetic dinuclear mixed-valence Mn(II)/Mn(III) complexes: building blocks for the higher nuclearity complexes. structure, magnetic properties, and density functional theory calculations.

Science.gov (United States)

Hänninen, Mikko M; Välivaara, Juha; Mota, Antonio J; Colacio, Enrique; Lloret, Francesc; Sillanpää, Reijo

2013-02-18

A series of six mixed-valence Mn(II)/Mn(III) dinuclear complexes were synthesized and characterized by X-ray diffraction. The reactivity of the complexes was surveyed, and structures of three additional trinuclear mixed-valence Mn(III)/Mn(II)/Mn(III) species were resolved. The magnetic properties of the complexes were studied in detail both experimentally and theoretically. All dinuclear complexes show ferromagnetic intramolecular interactions, which were justified on the basis of the electronic structures of the Mn(II) and Mn(III) ions. The large Mn(II)-O-Mn(III) bond angle and small distortion of the Mn(II) cation from the ideal square pyramidal geometry were shown to enhance the ferromagnetic interactions since these geometrical conditions seem to favor the orthogonal arrangement of the magnetic orbitals.

Influence of changes in the valence electronic configuration on the structure of L-X-ray spectra of molybdenum

International Nuclear Information System (INIS)

Polasik, M; Koziol, K; Slabkowska, K; Czarnota, M; Pajek, M

2009-01-01

Extensive multiconfiguration Dirac-Fock (MCDF) calculations with the inclusion of the transverse (Breit) interaction and QED corrections have been carried out on molybdenum to explain the dependence of the structure of Lα 1,2 and Lβ 1 lines on the changes in configurations of the valence electrons belonging to two different configuration types: three open-shell 4d 6-r 5s r (r = 2,1,0) configurations and one closed-shell 4d 4 3/2 5s 2 configuration. It has been found that the MCDF predictions for open-shell valence configurations (4d 4 5s 2 , 4d 5 5s 1 , 4d 6 5s 0 ) much better reproduce observed structure of Lα 1,2 lines in X-ray spectra of molybdenum than closed-shell 4d 4 3/2 5s 2 valence configuration. The influence of changes in the valence electronic configuration on the structure of L-X-ray spectra of molybdenum is noticeable. Moreover, the observation of the shapes of L-X-ray spectra seems to be very good method to investigate the changes of the valence electronic configuration caused by the chemical environment.

Structure and Magnetic Properties of a Mixed-Valence Heptanuclear Manganese Cluster.

Science.gov (United States)

Abbati, Gian Luca; Cornia, Andrea; Fabretti, Antonio C.; Caneschi, Andrea; Gatteschi, Dante

1998-07-27

Two novel polynuclear manganese(II,III) complexes have been synthesized by exploiting controlled methanolysis. A one-pot reaction of MnCl(2), NaOMe, dibenzoylmethane (Hdbm), and O(2) in anhydrous methanol, followed by recrystallization from MeOH/CHCl(3) mixtures, afforded the alkoxomanganese complexes [Mn(7)(OMe)(12)(dbm)(6)].CHCl(3).14MeOH (2) and [Mn(2)(OMe)(2)(dbm)(4)] (3). Complex 2 crystallizes in trigonal space group R&thremacr; with a = 14.439(2) Å, alpha = 86.34(1) degrees, and Z = 1. Complex 3 crystallizes in triclinic space group P&onemacr; with a = 9.612(1) Å, b = 10.740(1) Å, c = 13.168(1) Å, alpha = 80.39(1) degrees, beta = 87.66(1) degrees, gamma = 83.57(1) degrees, and Z = 1. The solid-state structure of 2 comprises a [Mn(6)(OMe)(12)(dbm)(6)] "crown" with crystallographically imposed 6-fold symmetry plus a central manganese ion. The layered Mn/O core mimics a fragment of the manganese oxide mineral lithiophorite. Conductivity measurements confirmed the nonionic character of 2 and suggested a mixed-valence Mn(II)(3)Mn(III)(4) formulation. The metrical parameters of the core were analyzed with the aid of bond-valence sum calculations. The central ion is essentially a valence-trapped Mn(II) ion, whereas the average Mn-O distances for the manganese ions of the "crown" are consistent with the presence of two Mn(II) and four Mn(III) ions. However, (1)H NMR spectra in solution strongly support valence localization and suggest that the observed solid-state structure may be a result of static disorder effects. Magnetic susceptibility vs T and magnetization vs field data at low temperature are consistent with an S = (17)/(2) ground state. Complex 3 is a symmetric alkoxo-bridged dimer. The two high-spin Mn(III) ions are antiferromagnetically coupled with J = 0.28(4) cm(-)(1), g = 1.983(2), and D = -2.5(4) cm(-)(1).

The valence electron structure and property analysis of TiC

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

The valence electron structure of TiC was calculated by using the empirical electron theory of solids and molecules. The calculated results show that with the increase of temperature the number of common electrons of TiC increases, which indicates that TiC has a good thermal sta-bility; and there exists a close relationship between hardness and brittleness of TiC. According to the number of lattice electrons, the differences among the crystals with different structures can be explained qualitatively. Using the "bond- strengthening factor", the differences of hardness among the crystals with different structures can also be qualitatively explained to some extent.

A study of the valence shell electronic states of s-triazine by photoabsorption spectroscopy and ab initio calculations

Energy Technology Data Exchange (ETDEWEB)

Holland, D.M.P., E-mail: david.holland@stfc.ac.uk [Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Shaw, D.A. [Daresbury Laboratory, Daresbury, Warrington, Cheshire WA4 4AD (United Kingdom); Stener, M.; Decleva, P. [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri, I-34127 Trieste (Italy); Consorzio Interuniversitario Nazionale per la Scienze e Tecnologia dei Materiali, INSTM, Unità di Trieste (Italy); CNR-IOM, Trieste (Italy); Coriani, S. [Dipartimento di Scienze Chimiche e Farmaceutiche, Università degli Studi di Trieste, Via L. Giorgieri, I-34127 Trieste (Italy); Consorzio Interuniversitario Nazionale per la Scienze e Tecnologia dei Materiali, INSTM, Unità di Trieste (Italy); Aarhus Institute of Advanced Studies, Aarhus University, 8000 Aarhus C (Denmark)

2016-09-30

Highlights: • The valence shell photoabsorption spectrum of s-triazine has been measured. • Electronic structure calculated with TDDFT and coupled cluster approaches. • Assignments proposed for Rydberg and valence states. • Mixing between Rydberg and valence states important. - Abstract: The absolute photoabsorption cross section of s-triazine has been measured between 4 and 40 eV, and is dominated by bands associated with valence states. Structure due to Rydberg excitations is both weak and irregular. Jahn-Teller interactions affect the vibronic structure observed in the Rydberg absorption bands due to excitation from the 1e″ or 6e′ orbitals. The interpretation of the experimental spectrum has been guided by transition energies and oscillator strengths, for Rydberg and valence states, calculated with the time-dependent version of density functional theory and with the coupled cluster linear response approach. The theoretical studies indicate that Rydberg/Rydberg and Rydberg/valence mixing is important.

Experimental determination of the π meson structure functions by the Drell-Yan mechanism

International Nuclear Information System (INIS)

Badier, J.; Bourotte, J.; Mine, P.; Vanderhaghen, R.; Weisz, S.; Boucrot, J.; Callot, O.; Decamp, D.; Karyotakis, Y.; Lefrancois, J.; Crozon, M.; Delpierre, P.; Leray, T.; Maillard, J.; Tilquin, A.; Valentin, J.

1983-01-01

We have studied high statistics samples of dimuon events (proportional35,000) produced from πsup(+-) on platinum target in the mass interval 4.2 2 sigma/dx 1 dx 2 to π + and π - data. At 200 GeV, the simultaneous use of π + and π - data allows a separate determination of the valence and sea structure functions of the π. Furthermore, the 150 and 280 GeV data allow an accurate determination of the shape of the valence structure function and give an estimate of its evolution between Q 2 =25 and 50 GeV 2 . (orig.)

Valence band structures of InAs/GaAs quantum rings using the Fourier transform method

International Nuclear Information System (INIS)

Jia Boyong; Yu Zhongyuan; Liu Yumin

2009-01-01

The valence band structures of strained InAs/GaAs quantum rings are calculated, with the four-band k · p model, in the framework of effective-mass envelope function theory. When determining the Hamiltonian matrix elements, we develop the Fourier transform method instead of the widely used analytical integral method. Using Fourier transform, we have investigated the energy levels as functions of the geometrical parameters of the rings and compared our results with those obtained by the analytical integral method. The results show that the energy levels in the quantum rings change dramatically with the inner radius, outer radius, average radius, width, height of the ring and the distance between two adjacent rings. Our method can be adopted in low-dimensional structures with arbitrary shape. Our results are consistent with those in the literature and should be helpful for studying and fabricating optoelectronic devices

Localized description of valence fluctuations

International Nuclear Information System (INIS)

Alascio, B.; Allub, R.; Aligia, A.

1979-07-01

The authors set up a model for intermediate valence equivalent to the ''atomic'' limit of the Anderson Hamiltonian. Detailed analysis of this model shows that most of the essential characteristics of valence fluctuators are already present in this crudely simplified Hamiltonian. The spin-spin and the 4f charge-charge correlation functions are studied and it is shown that it is possible to define a spin fluctuation frequency ωsub(s.f.) and a charge fluctuation frequency ωsub(ch.f.).ωsub(s.f.) and ωsub(ch.f.) can differ considerably for some values of the parameters of the model. The magnetic susceptibility and the specific heat are calculated as functions of temperature and it is shown how the results simulate the behaviour found in valence fluctuators. (author)

Valence electron structure of cast iron and graphltization behaviour criterion of elements

Institute of Scientific and Technical Information of China (English)

刘志林; 李志林; 孙振国; 杨晓平; 陈敏

1995-01-01

The valence electron structure of common alloy elements in phases of cast iron is calculated- The relationship between the electron structure of alloy elements and equilibrium, non-equilibrium solidification and graphitization is revealed by defining the bond energy of the strongest bond in a phase as structure formation factor S. A criterion of graphitization behaviour of elements is advanced with the critical value of the structure formation factor of graphite and the n of the strongest covalent bond in cementite. It is found that this theory conforms to practice very well when the criterion is applied to the common alloy elements.

Determination of the pion and kaon structure functions

International Nuclear Information System (INIS)

Aitkenhead, W.; Barton, D.S.; Brandenburg, G.W.; Busza, W.; Dobrowolski, T.; Friedman, J.I.; Kendall, H.W.; Lyons, T.; Nelson, B.; Rosenson, L.; Toy, W.; Verdier, R.; Votta, L.; Chiaradia, M.T.; DeMarzo, C.; Favuzzi, C.; Germinario, G.; Guerriero, L.; LaVopa, P.; Maggi, G.; Posa, F.; Selvaggi, G.; Spinelli, P.; Waldner, F.; Brenner, A.E.; Carey, D.C.; Elias, J.E.; Garbincius, P.H.; Mikenberg, G.; Polychronakos, V.A.; Meunier, R.; Cutts, D.; Dulude, R.S.; Lanou, R.E. Jr.; Massimo, J.T.

1980-01-01

Quark structure functions have been extracted from low-p/sub T/ inclusive hadron production data for the pion and kaon with use of the recombination model. n/sup π/=1.0 +- 0.1 and n/sup K/=2.5 +- 0.6 is obtained, where n is the leading (1-x) power of the nonstrange--valence-quark distribution. Both the pion and kaon nonstrange--sea-quark functions have napprox. =3.5

Determination of the pion structure function from muon-pair production

International Nuclear Information System (INIS)

Newman, C.B.; Anderson, K.J.; Coleman, R.N.; Hogan, G.E.; Karhi, K.P.; McDonald, K.T.; Pilcher, J.E.; Rosenberg, E.I.; Sanders, G.H.; Smith, A.J.S.; Thaler, J.J.

1979-01-01

Data on muon-pair production by pions are used to determine the momentum distribution for valence quarks in the pion. The shape of a nucleon structure function is also obtained and is compared with a calculation based on existing data

Orbital momentum distribution and binding energies for the complete valence shell of molecular bromine

International Nuclear Information System (INIS)

Frost, L.; Grisogono, A.M.; Weigold, E.

1987-08-01

The binding energy spectrum of Br 2 has been recorded in both the outer and inner valence regions using electron momentum spectroscopy. The measurements are compared with the results of several Green's function calculations using different approximations and based on both polarized and unpolarized wave functions. The inner valence region, observed for the first time, is found to exhibit complex structure that is shown to be due to many-body effects, thus indicating a breakdown of the simple MO picture for ionization in this region. Momentum distributions for the three outer valence orbitals are also measured and compared with spherically averaged calculations using the target Hartree-Fock and plane wave impulse approximations. The effect of polarization functions in the basis set is investigated. Orbital density maps in both momentum and position space have been calculated and compared with the experimental measurements

Analysis of the valence electronic structures and calculation of the physical properties of Fe,Co,and Ni

Institute of Scientific and Technical Information of China (English)

无

2009-01-01

The valence electronic structures of Fe, Co and Ni have been investigated with Empirical Electron Theory of Solids and Molecules. The magnetic moments, Curie temperature, cohesive energy and melting point have been calculated according to the valence electronic structure. These calculations fit the experimental data very well. Based on the calculations, the magnetic moments are proportional to the number of 3d magnetic electrons. Curie temperatures are related to the magnetic electrons and the bond lengths between magnetic atoms. Cohesive energies increase with the increase of the number of covalent electrons, and the decrease of the number of magnetic and dumb pair electrons. The melting point is mainly related to the number of covalent electron pairs distributed in the strongest bond. The contribution from the lattice electrons is very small, the dumb pair electrons weaken the melting point; however, the contribution to melting point of the magnetic electrons can be neglected. It reveals that the magnetic and thermal properties are closely related to the valence electronic structures, and the changes or transitions between the electrons obviously affect the physical properties.

Levels of valence

Directory of Open Access Journals (Sweden)

Vera eShuman

2013-05-01

Full Text Available The distinction between the positive and the negative is fundamental in our emotional life. In appraisal theories, in particular in the component process model of emotion (Scherer, 1984, 2010, qualitatively different types of valence are proposed based on appraisals of (unpleasantness, goal obstructiveness/conduciveness, low or high power, self- (incongruence, and moral badness/goodness. This multifaceted conceptualization of valence is highly compatible with the frequent observation of mixed feelings in real life. However, it seems to contradict the one-dimensional conceptualization of valence often encountered in psychological theories, and the notion of valence as a common currency used to explain choice behavior. Here, we propose a framework to integrate the seemingly disparate conceptualizations of multifaceted valence and one-dimensional valence by suggesting that valence should be conceived at different levels, micro and macro. Micro-valences correspond to qualitatively different types of evaluations, potentially resulting in mixed feelings, whereas one-dimensional macro-valence corresponds to an integrative common currency to compare alternatives for choices. We propose that conceptualizing levels of valence may focus research attention on the mechanisms that relate valence at one level (micro to valence at another level (macro, leading to new hypotheses and addressing various concerns that have been raised about the valence concept, such as the valence-emotion relation.

Dimensionality and its effects upon the valence electronic structure of ordered metallic systems

International Nuclear Information System (INIS)

Tobin, J.G.

1983-07-01

The system c(10x2)Ag/Cu(001) was investigated with Angle-Resolved Photoemission (ARP), Low Energy Electron Diffraction (LEED) and Auger Electron Spectroscopy (AES). LEED and AES provided the calibration of a quartz microbalance used to measure the amount of silver evaporated onto the copper single crystal and also established the monolayer geometrical structure at one monolayer exposure. An off-normal ARP bandmapping study performed with polarized HeI and NeI radiation demonstrated the electronically two-dimensional nature of the silver d-bands at coverages of near one monolayer. The states at the surface Brillouin Zone center were assigned upon the basis of their polarization dependences and a structural model of hexagonal symmetry. A normal emission ARP experiment was performed at the Stanford Synchrotron Radiation Laboratory (SSRL) over the photon energy range of 6 to 32 eV. Data from it documented the evolution of the valence electronic structure of the silver overlayer from a two-dimensional hexagonal valence to a three-dimensional behavior converging towards that of bulk Ag(111). A structural study was attempted using the ARP technique of Normal Emission Photoelectron Diffraction over the photon energy range of 3.4 to 3.7 keV at SSRL, the results of which are inconclusive

Levels of Valence

Science.gov (United States)

Shuman, Vera; Sander, David; Scherer, Klaus R.

2013-01-01

The distinction between the positive and the negative is fundamental in our emotional life. In appraisal theories, in particular in the component process model of emotion (Scherer, 1984, 2010), qualitatively different types of valence are proposed based on appraisals of (un)pleasantness, goal obstructiveness/conduciveness, low or high power, self-(in)congruence, and moral badness/goodness. This multifaceted conceptualization of valence is highly compatible with the frequent observation of mixed feelings in real life. However, it seems to contradict the one-dimensional conceptualization of valence often encountered in psychological theories, and the notion of valence as a common currency used to explain choice behavior. Here, we propose a framework to integrate the seemingly disparate conceptualizations of multifaceted valence and one-dimensional valence by suggesting that valence should be conceived at different levels, micro and macro. Micro-valences correspond to qualitatively different types of evaluations, potentially resulting in mixed feelings, whereas one-dimensional macro-valence corresponds to an integrative “common currency” to compare alternatives for choices. We propose that conceptualizing levels of valence may focus research attention on the mechanisms that relate valence at one level (micro) to valence at another level (macro), leading to new hypotheses, and addressing various concerns that have been raised about the valence concept, such as the valence-emotion relation. PMID:23717292

How Body Orientation Affects Concepts of Space, Time and Valence: Functional Relevance of Integrating Sensorimotor Experiences during Word Processing.

Directory of Open Access Journals (Sweden)

Martin Lachmair

Full Text Available The aim of the present study was to test the functional relevance of the spatial concepts UP or DOWN for words that use these concepts either literally (space or metaphorically (time, valence. A functional relevance would imply a symmetrical relationship between the spatial concepts and words related to these concepts, showing that processing words activate the related spatial concepts on one hand, but also that an activation of the concepts will ease the retrieval of a related word on the other. For the latter, the rotation angle of participant's body position was manipulated either to an upright or a head-down tilted body position to activate the related spatial concept. Afterwards participants produced in a within-subject design previously memorized words of the concepts space, time and valence according to the pace of a metronome. All words were related either to the spatial concept UP or DOWN. The results including Bayesian analyses show (1 a significant interaction between body position and words using the concepts UP and DOWN literally, (2 a marginal significant interaction between body position and temporal words and (3 no effect between body position and valence words. However, post-hoc analyses suggest no difference between experiments. Thus, the authors concluded that integrating sensorimotor experiences is indeed of functional relevance for all three concepts of space, time and valence. However, the strength of this functional relevance depends on how close words are linked to mental concepts representing vertical space.

Valence electronic structure of tantalum carbide and nitride

Institute of Scientific and Technical Information of China (English)

FAN; ChangZeng

2007-01-01

The valence electronic structures of tantalum carbide (TaC) and tantalum nitride (TaN) are studied by using the empirical electronic theory (EET). The results reveal that the bonds of these compounds have covalent, metallic and ionic characters. For a quantitative analysis of the relative strength of these components, their ionicities have been calculated by implanting the results of EET to the PVL model. It has been found that the ionicity of tantalum carbide is smaller than that of tantalum nitride. The EET results also reveal that the covalent electronic number of the strongest bond in the former is larger than that of the latter. All these suggest that the covalent bond of TaC is stronger than that of TaN, which coincides to that deduced from the first-principles method.……

Valence electronic structure of tantalum carbide and nitride

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

@@ The valence electronic structures of tantalum carbide (TaC) and tantalum nitride (TaN) are studied by using the empirical electronic theory (EET). The results reveal that the bonds of these compounds have covalent, metallic and ionic characters. For a quantitative analysis of the relative strength of these components, their ionicities have been calculated by implanting the results of EET to the PVL model. It has been found that the ionicity of tantalum carbide is smaller than that of tantalum nitride. The EET results also reveal that the covalent electronic number of the strongest bond in the former is larger than that of the latter. All these suggest that the covalent bond of TaC is stronger than that of TaN, which coincides to that deduced from the first-principles method.

Heparan sulfate chain valency controls syndecan-4 function in cell adhesion

DEFF Research Database (Denmark)

Gopal, Sandeep; Bober, Adam; Whiteford, James R

2010-01-01

, clustering of one-chain syndecan-4 forms with antibodies overcame the block, indicating that valency of interactions with ligands is a key component of syndecan-4 function. Measurements of focal contact/adhesion size and focal adhesion kinase phosphorylation correlated with syndecan-4 status and alpha...... of the core protein cytoplasmic domain, though not interactions with PDZ proteins. A second key requirement is multiple heparan sulfate chains. Mutant syndecan-4 with no chains, or only one chain, failed to restore the wild type phenotype, while those expressing two or three were competent. However......-smooth muscle actin organization, being reduced where syndecan-4 function was compromised by a lack of multiple heparan sulfate chains....

The valence state of Yb metal under high pressure determined by XANES measurement up to 34.6 GPa

International Nuclear Information System (INIS)

Fuse, Akinori; Nakamoto, Go; Kurisu, Makio; Ishimatsu, Naoki; Tanida, Hajime

2004-01-01

The purpose of this study was to accurately determine the valency of Yb at high pressure and room temperature and to clarify the relation between the valence state and the crystal structure of Yb metal. L III -edge X-ray absorption near-edge structure (XANES) spectra were measured to determine the valence state of Yb metal in the pressure range from 0 to 34.6 GPa at room temperature, using a diamond anvil cell (DAC) and synchrotron radiation at SPring-8. In the fcc phase, Yb metal exhibits mixed valence (the mean valence ν-bar >2.1). At the fcc-to-bcc phase transition, a 0.1 jump is found in ν-bar. In the bcc phase, ν-bar(P) is an increasing function of pressure with downward curvature, reaching only 2.55 at 26 GPa. The ν-bar is only 2.65 in the hcp phase at 34.6 GPa. A tendency for saturation in ν-bar(P) to values smaller than 3.0 is found

Valence nucleons in self-consistent fields

International Nuclear Information System (INIS)

Di Toro, M.; Lomnitz-Adler, J.

1978-01-01

An iterative approach to determine directly the best Hartree-Fock one-body density rho is extended by expressing rho in terms of a core and a valence part and allowing for general crossings of occupied and unoccupied levels in the valence part. Results are shown for 152 Sm and a microscopic analysis of the core structure of deformed light nuclei is carried out. (author)

The triple-pomeron regime and structure function of the pomeron in diffractive deep inelastic scattering at very small x

International Nuclear Information System (INIS)

Nikolaev, N.N.; Zakharov, B.G.

1994-01-01

We develop the novel description of diffractive deep inelastic scattering based on the technique of lightcone wave functions of multiparton Fock states of the photon. The technique takes advantage of the exact diagonalization of the diffractive S-matrix in the dipole-cross section representation. In this paper we derive properties of the diffractive dissociation of virtual photons in the triple-pomeron regime. We demonstrate that the photon-pomeron interactions can be described by the partonic structure function, which satisfies the conventional GLDAP evolution equations. We identify the valence and sea (anti) quark and the valence gluon structure functions of the pomeron. We show how the gluon structure of the pomeron can be described by the constituent gluon wave function. We derive the leading unitarization correction to the rising structure functions at small x and conclude that the unitarized structure function satisfies the linear GLDAP evolution equations. This result holds even when the multipomeron exchanges are included. (orig.)

Effect of Pressure on Valence and Structural Properties of YbFe₂Ge₂ Heavy Fermion Compound A Combined Inelastic X-ray Spectroscopy, X-ray Diffraction, and Theoretical Investigation

Energy Technology Data Exchange (ETDEWEB)

Kumar, Ravhi S.; Svane, Axel; Vaitheeswaran; #8741; , Ganapathy; Kanchana, Venkatakrishnan; Antonio, Daniel; Cornelius, Andrew L.; Bauer, Eric D.; Xiao, Yuming; Chow, Paul (Aarhus); (CIW); (Hyderabad - India); (IIT-India); (LANL); (UNLV)

2016-06-03

The crystal structure and the Yb valence of the YbFe₂Ge₂ heavy fermion compound was measured at room temperature and under high pressures using high-pressure powder X-ray diffraction and X-ray absorption spectroscopy via both partial fluorescence yield and resonant inelastic X-ray emission techniques. Furthermore, the measurements are complemented by first-principles density functional theoretical calculations using the self-interaction corrected local spin density approximation investigating in particular the magnetic structure and the Yb valence. While the ThCr₂Si₂-type tetragonal (I4/mmm) structure is stable up to 53 GPa, the X-ray emission results show an increase of the Yb valence from v = 2.72(2) at ambient pressure to v = 2.93(3) at ~9 GPa, where at low temperature a pressure-induced quantum critical state was reported.

Micro-Valences: Affective valence in neutral everyday objects

OpenAIRE

Sophie eLebrecht; Moshe eBar; Lisa F Barrett; Michael J Tarr

2012-01-01

Affective valence influences both our cognition and our perception of the world. Indeed, the speed and quality with which we recognize objects in a visual scene can vary dramatically depending on its affective content. However, affective processing of visual objects has been typically studied using only stimuli with strong affective valences (e.g., guns or roses). Here we explore whether affective valence must be strong or obvious to exert an effect on our perception. We conclude that the maj...

Features of the core-valence luminescence and electron energy band structure of A1-xCsxCaCl3 (A = K,Rb) crystals

International Nuclear Information System (INIS)

Chornodolskyy, Ya; Stryganyuk, G; Syrotyuk, S; Voloshinovskii, A; Rodnyi, P

2007-01-01

From luminescence spectroscopy of CsCaCl 3 , Rb 1-x Cs x CaCl 3 and K 1-x Cs x CaCl 3 crystals, we have found evidence for intrinsic and impurity core-valence luminescence due to the radiative recombination of valence electrons with the holes of intrinsic or impurity 5p Cs + core states. The structural similarity of core-valence luminescence spectra has been revealed for the A 1-x Cs x CaCl 3 (A = K,Rb) crystals investigated. The electron energy structure of the CsCaCl 3 crystal has been calculated using the pseudopotential approach taking into account the gradient corrections for the exchange-correlation energy. The calculated density of the electronic states of CsCaCl 3 has been compared with corresponding parameters obtained from the analysis of core-valence luminescence spectra

Emotional valence and the free-energy principle.

Science.gov (United States)

Joffily, Mateus; Coricelli, Giorgio

2013-01-01

The free-energy principle has recently been proposed as a unified Bayesian account of perception, learning and action. Despite the inextricable link between emotion and cognition, emotion has not yet been formulated under this framework. A core concept that permeates many perspectives on emotion is valence, which broadly refers to the positive and negative character of emotion or some of its aspects. In the present paper, we propose a definition of emotional valence in terms of the negative rate of change of free-energy over time. If the second time-derivative of free-energy is taken into account, the dynamics of basic forms of emotion such as happiness, unhappiness, hope, fear, disappointment and relief can be explained. In this formulation, an important function of emotional valence turns out to regulate the learning rate of the causes of sensory inputs. When sensations increasingly violate the agent's expectations, valence is negative and increases the learning rate. Conversely, when sensations increasingly fulfil the agent's expectations, valence is positive and decreases the learning rate. This dynamic interaction between emotional valence and learning rate highlights the crucial role played by emotions in biological agents' adaptation to unexpected changes in their world.

Emotional valence and the free-energy principle.

Directory of Open Access Journals (Sweden)

Mateus Joffily

Full Text Available The free-energy principle has recently been proposed as a unified Bayesian account of perception, learning and action. Despite the inextricable link between emotion and cognition, emotion has not yet been formulated under this framework. A core concept that permeates many perspectives on emotion is valence, which broadly refers to the positive and negative character of emotion or some of its aspects. In the present paper, we propose a definition of emotional valence in terms of the negative rate of change of free-energy over time. If the second time-derivative of free-energy is taken into account, the dynamics of basic forms of emotion such as happiness, unhappiness, hope, fear, disappointment and relief can be explained. In this formulation, an important function of emotional valence turns out to regulate the learning rate of the causes of sensory inputs. When sensations increasingly violate the agent's expectations, valence is negative and increases the learning rate. Conversely, when sensations increasingly fulfil the agent's expectations, valence is positive and decreases the learning rate. This dynamic interaction between emotional valence and learning rate highlights the crucial role played by emotions in biological agents' adaptation to unexpected changes in their world.

Exact ground-state correlation functions of one-dimenisonal strongly correlated electron models with resonating-valence-bond ground state

International Nuclear Information System (INIS)

Yamanaka, Masanori; Honjo, Shinsuke; Kohmoto, Mahito

1996-01-01

We investigate one-dimensional strongly correlated electron models which have the resonating-valence-bond state as the exact ground state. The correlation functions are evaluated exactly using the transfer matrix method for the geometric representations of the valence-bond states. In this method, we only treat matrices with small dimensions. This enables us to give analytical results. It is shown that the correlation functions decay exponentially with distance. The result suggests that there is a finite excitation gap, and that the ground state is insulating. Since the corresponding noninteracting systems may be insulating or metallic, we can say that the gap originates from strong correlation. The persistent currents of the present models are also investigated and found to be exactly vanishing

Architectural Representation of Valence in the Limbic System

Science.gov (United States)

Namburi, Praneeth; Al-Hasani, Ream; Calhoon, Gwendolyn G; Bruchas, Michael R; Tye, Kay M

2016-01-01

In order to thrive, animals must be able to recognize aversive and appetitive stimuli within the environment and subsequently initiate appropriate behavioral responses. This assignment of positive or negative valence to a stimulus is a key feature of emotional processing, the neural substrates of which have been a topic of study for several decades. Until recently, the result of this work has been the identification of specific brain regions, such as the basolateral amygdala (BLA) and nucleus accumbens (NAc), as important to valence encoding. The advent of modern tools in neuroscience has allowed further dissection of these regions to identify specific populations of neurons signaling the valence of environmental stimuli. In this review, we focus upon recent work examining the mechanisms of valence encoding, and provide a model for the systematic investigation of valence within anatomically-, genetically-, and functionally defined populations of neurons. PMID:26647973

Valence evaluation with approaching or withdrawing cues: directly testing valence-arousal conflict theory.

Science.gov (United States)

Wang, Yan Mei; Li, Ting; Li, Lin

2017-07-19

The valence-arousal conflict theory assumes that both valence and arousal will trigger approaching or withdrawing tendencies. It also predicts that the speed of processing emotional stimuli will depend on whether valence and arousal trigger conflicting or congruent motivational tendencies. However, most previous studies have provided evidence of the interaction between valence and arousal only, and have not provided direct proof of the interactive links between valence, arousal and motivational tendencies. The present study provides direct evidence for the relationship between approach-withdrawal tendencies and the valence-arousal conflict. In an empirical test, participants were instructed to judge the valence of emotional words after visual-spatial cues that appeared to be either approaching or withdrawing from participants. A three-way interaction (valence, arousal, and approach-withdrawal tendency) was observed such that the response time was shorter if participants responded to a negative high-arousal stimulus after a withdrawing cue, or to a positive low-arousal stimulus after an approaching cue. These findings suggest that the approach-withdrawal tendency indeed plays a crucial role in valence-arousal conflict, and that the effect depends on the congruency of valence, arousal and tendency at an early stage of processing.

Probing Transient Valence Orbital Changes with Picosecond Valence-to-Core X-ray Emission Spectroscopy

DEFF Research Database (Denmark)

March, Anne Marie; Assefa, Tadesse A.; Boemer, Christina

2017-01-01

We probe the dynamics of valence electrons in photoexcited [Fe(terpy)2]2+ in solution to gain deeper insight into the Fe ligand bond changes. We use hard X-ray emission spectroscopy (XES), which combines element specificity and high penetration with sensitivity to orbital structure, making...... valence orbitals to the nascent core-hole. Vtc-XES offers particular insight into the molecular orbitals directly involved in the light-driven dynamics; a change in the metal ligand orbital overlap results in an intensity reduction and a blue energy shift in agreement with our theoretical calculations...... and more subtle features at the highest energies reflect changes in the frontier orbital populations....

Unpolarized structure functions and the parton distributions for nucleon in an independent quark model

International Nuclear Information System (INIS)

Barik, N.; Mishra, R.N.

2001-01-01

Considering the nucleon as consisting entirely of its valence quarks confined independently in a scalar-vector harmonic potential; unpolarized structure functions F 1 (x, μ 2 ) and F 2 (x, μ 2 ) are derived in the Bjorken limit under certain simplifying assumptions; from which valence quark distribution functions u v (x, μ 2 ) and d v (x, μ 2 ) are appropriately extracted satisfying the normalization constraints. QCD-evolution of these input distributions from a model scale of μ 2 = 0.07 GeV 2 to a higher Q 2 scale of Q 0 2 = 15 GeV 2 yields xu v (x, Q 0 2 ) and xd v (x, Q 0 2 ) in good agreement with experimental data. The gluon and sea-quark distributions such as G (x, Q 0 2 ) and q s (x, Q 0 2 ) are dynamically generated with a reasonable qualitative agreement with the available data; using the leading order renormalization group equations with appropriate valence-quark distributions as the input. (author)

Band structure and dielectric function of TlInTe2

International Nuclear Information System (INIS)

Wakita, K.; Shim, Y.; Orudzhev, G.; Mamedov, N.; Hashimzade, F.

2006-01-01

The band structure of ternary chain TlInTe 2 was calculated with allowance for non-locality of ionic pseudo-potentials. The dielectric function, as well as the effective masses of holes and electrons, the effective number of valence electrons, and the function of characteristic losses were determined. The results of comparison between the calculated dielectric function and the one obtained ellipsometrically in the spectral range from 0.85 to 6 eV are quite favorable. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (Abstract Copyright [2006], Wiley Periodicals, Inc.)

Plutonium valence state distributions

International Nuclear Information System (INIS)

Silver, G.L.

1974-01-01

A calculational method for ascertaining equilibrium valence state distributions of plutonium in acid solutions as a function of the plutonium oxidation number and the solution acidity is illustrated with an example. The method may be more practical for manual use than methods based upon polynomial equations. (T.G.)

Valence photoelectron spectrum of KBr: Effects of electron correlation

International Nuclear Information System (INIS)

Calo, A.; Huttula, M.; Patanen, M.; Aksela, H.; Aksela, S.

2008-01-01

The valence photoelectron spectrum has been measured for molecular KBr. Experimental energies of the main and satellite structures have been compared with the results of ab initio calculations based on molecular orbital theory including configuration and multiconfiguration interaction approaches. Comparison between the experimental KBr spectrum and previously reported Kr valence photoelectron spectrum has also been performed in order to find out if electron correlation is of the same importance in the valence ionized state of KBr as in the corresponding state of Kr

Atomic contributions to the valence band photoelectron spectra of metal-free, iron and manganese phthalocyanines

Energy Technology Data Exchange (ETDEWEB)

Bidermane, I., E-mail: ieva.bidermane@physics.uu.se [Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala (Sweden); Institut des Nanosciences de Paris, UPMC Univ. Paris 06, CNRS UMR 7588, F-75005 Paris (France); Brumboiu, I.E. [Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala (Sweden); Totani, R. [Department of Physical and Chemical Sciences, University of L’Aquila, Via Vetoio, Coppito, I-67010 L’Aquila (Italy); Grazioli, C. [CNR-IOM, Laboratorio TASC, ss. 14 km. 163.5, Basovizza, 34149 Trieste (Italy); Departement of Chemical and Pharmaceutical Sciences, University of Trieste (Italy); Shariati-Nilsson, M.N.; Herper, H.C.; Eriksson, O.; Sanyal, B. [Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala (Sweden); Ressel, B. [University of Nova Gorica, Vipavska Cesta 11c, 5270 Ajdovščina (Slovenia); Simone, M. de [CNR-IOM, Laboratorio TASC, ss. 14 km. 163.5, Basovizza, 34149 Trieste (Italy); Lozzi, L. [Department of Physical and Chemical Sciences, University of L’Aquila, Via Vetoio, Coppito, I-67010 L’Aquila (Italy); Brena, B.; Puglia, C. [Department of Physics and Astronomy, Uppsala University, Box-516, 75120 Uppsala (Sweden)

2015-11-15

Highlights: • In detail comparison between the valence band structure of H{sub 2}Pc, FePc and MnPc. • Comparison between the gas phase samples and thin evaporated films on Au (1 1 1). • Detailed analysis of the atomic orbital contributions to the valence band features. • DFT/HSE06 study of the valence band electronic structure of H{sub 2}Pc, FePc and MnPc. - Abstract: The present work reports a photoelectron spectroscopy study of the low-energy region of the valence band of metal-free phthalocyanine (H{sub 2}Pc) compared with those of iron phthalocyanine (FePc) and manganese phthalocyanine (MnPc). We have analysed in detail the atomic orbital composition of the valence band both experimentally, by making use of the variation in photoionization cross-sections with photon energy, and theoretically, by means of density functional theory. The atomic character of the Highest Occupied Molecular Orbital (HOMO), reflected on the outermost valence band binding energy region, is different for MnPc as compared to the other two molecules. The peaks related to the C 2p contributions, result in the HOMO for H{sub 2}Pc and FePc and in the HOMO-1 for MnPc as described by the theoretical predictions, in very good agreement with the experimental results. The DFT simulations, discerning the atomic contribution to the density of states, indicate how the central metal atom interacts with the C and N atoms of the molecule, giving rise to different partial and total density of states for these three Pc molecules.

Lattice and Valence Electronic Structures of Crystalline Octahedral Molybdenum Halide Clusters-Based Compounds, Cs2[Mo6X14] (X = Cl, Br, I), Studied by Density Functional Theory Calculations.

Science.gov (United States)

Saito, Norio; Cordier, Stéphane; Lemoine, Pierric; Ohsawa, Takeo; Wada, Yoshiki; Grasset, Fabien; Cross, Jeffrey S; Ohashi, Naoki

2017-06-05

The electronic and crystal structures of Cs 2 [Mo 6 X 14 ] (X = Cl, Br, I) cluster-based compounds were investigated by density functional theory (DFT) simulations and experimental methods such as powder X-ray diffraction, ultraviolet-visible spectroscopy, and X-ray photoemission spectroscopy (XPS). The experimentally determined lattice parameters were in good agreement with theoretically optimized ones, indicating the usefulness of DFT calculations for the structural investigation of these clusters. The calculated band gaps of these compounds reproduced those experimentally determined by UV-vis reflectance within an error of a few tenths of an eV. Core-level XPS and effective charge analyses indicated bonding states of the halogens changed according to their sites. The XPS valence spectra were fairly well reproduced by simulations based on the projected electron density of states weighted with cross sections of Al K α , suggesting that DFT calculations can predict the electronic properties of metal-cluster-based crystals with good accuracy.

In-medium pion valence distributions in a light-front model

Energy Technology Data Exchange (ETDEWEB)

Melo, J.P.B.C. de, E-mail: joao.mello@cruzeirodosul.edu.br [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); Tsushima, K. [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); Ahmed, I. [Laboratório de Física Teórica e Computacional – LFTC, Universidade Cruzeiro do Sul, 01506-000 São Paulo (Brazil); National Center for Physics, Quaidi-i-Azam University Campus, Islamabad 45320 (Pakistan)

2017-03-10

Pion valence distributions in nuclear medium and vacuum are studied in a light-front constituent quark model. The in-medium input for studying the pion properties is calculated by the quark-meson coupling model. We find that the in-medium pion valence distribution, as well as the in-medium pion valence wave function, are substantially modified at normal nuclear matter density, due to the reduction in the pion decay constant.

Intersite interactions and susceptibility in mixed valence systems

International Nuclear Information System (INIS)

Xiaoqian Wang; Gao Lin; Bingjian Ni; Fusui Liu.

1985-10-01

This paper considers the effect of intersite processes on the susceptibility in mixed valence system. The method of thermodynamical perturbation used in this paper can also be generalized to study other properties of mixed valence system. The general formula of partition function of two-site interactions for the mixed valence system is given. The numerical calculations show that the intersite interaction is large enough to explain the minimum of susceptibility discovered in experiments. The different types of our theoretical curves predict that the susceptibility should exhibit a rich variety of behaviour at low temperature for various materials. (author)

Human Amygdala Represents the Complete Spectrum of Subjective Valence

Science.gov (United States)

Jin, Jingwen; Zelano, Christina; Gottfried, Jay A.

2015-01-01

Although the amygdala is a major locus for hedonic processing, how it encodes valence information is poorly understood. Given the hedonic potency of odor stimuli and the amygdala's anatomical proximity to the peripheral olfactory system, we combined high-resolution fMRI with pattern-based multivariate techniques to examine how valence information is encoded in the amygdala. Ten human subjects underwent fMRI scanning while smelling 9 odorants that systematically varied in perceived valence. Representational similarity analyses showed that amygdala codes the entire dimension of valence, ranging from pleasantness to unpleasantness. This unidimensional representation significantly correlated with self-reported valence ratings but not with intensity ratings. Furthermore, within-trial valence representations evolved over time, prioritizing earlier differentiation of unpleasant stimuli. Together, these findings underscore the idea that both spatial and temporal features uniquely encode pleasant and unpleasant odor valence in the amygdala. The availability of a unidimensional valence code in the amygdala, distributed in both space and time, would create greater flexibility in determining the pleasantness or unpleasantness of stimuli, providing a mechanism by which expectation, context, attention, and learning could influence affective boundaries for guiding behavior. SIGNIFICANCE STATEMENT Our findings elucidate the mechanisms of affective processing in the amygdala by demonstrating that this brain region represents the entire valence dimension from pleasant to unpleasant. An important implication of this unidimensional valence code is that pleasant and unpleasant valence cannot coexist in the amygdale because overlap of fMRI ensemble patterns for these two valence extremes obscures their unique content. This functional architecture, whereby subjective valence maps onto a pattern continuum between pleasant and unpleasant poles, offers a robust mechanism by which context

Human Amygdala Tracks a Feature-Based Valence Signal Embedded within the Facial Expression of Surprise.

Science.gov (United States)

Kim, M Justin; Mattek, Alison M; Bennett, Randi H; Solomon, Kimberly M; Shin, Jin; Whalen, Paul J

2017-09-27

Human amygdala function has been traditionally associated with processing the affective valence (negative vs positive) of an emotionally charged event, especially those that signal fear or threat. However, this account of human amygdala function can be explained by alternative views, which posit that the amygdala might be tuned to either (1) general emotional arousal (activation vs deactivation) or (2) specific emotion categories (fear vs happy). Delineating the pure effects of valence independent of arousal or emotion category is a challenging task, given that these variables naturally covary under many circumstances. To circumvent this issue and test the sensitivity of the human amygdala to valence values specifically, we measured the dimension of valence within the single facial expression category of surprise. Given the inherent valence ambiguity of this category, we show that surprised expression exemplars are attributed valence and arousal values that are uniquely and naturally uncorrelated. We then present fMRI data from both sexes, showing that the amygdala tracks these consensus valence values. Finally, we provide evidence that these valence values are linked to specific visual features of the mouth region, isolating the signal by which the amygdala detects this valence information. SIGNIFICANCE STATEMENT There is an open question as to whether human amygdala function tracks the valence value of cues in the environment, as opposed to either a more general emotional arousal value or a more specific emotion category distinction. Here, we demonstrate the utility of surprised facial expressions because exemplars within this emotion category take on valence values spanning the dimension of bipolar valence (positive to negative) at a consistent level of emotional arousal. Functional neuroimaging data showed that amygdala responses tracked the valence of surprised facial expressions, unconfounded by arousal. Furthermore, a machine learning classifier identified

A thermodynamical analysis of the π and K meson valence structure functions

International Nuclear Information System (INIS)

Angelini, C.; Pazzi, R.

1982-01-01

The π and K meson valance structure functions are analysed in the framework of a thermodynamical model already applied to the nucleon. We obtain a simple expression which reproduces quite well the data for chi > 0.3. The effective temperatures are found to be of the order of 20 MeV for the pion and 65 MeV for the kaon. (orig.)

Valence instabilities as a source of actinide system inconsistencies

International Nuclear Information System (INIS)

Sandenaw, T.A.

1979-01-01

Light actinide elements alone, and in some of their alloys, may exist as a static or dynamic mixture of two configurations. Such a state can explain both a resistivity maximum and lack of magnetic order observed in so many actinide materials, and still be compatible with the existence of f-electrons in narrow bands. Impurity elements may stabilize slightly different intermediate valence states in U, Np, and Pu, thus contributing to inconsistencies in published results. The physical property behavior of mixed-valence, rare-earth compounds is very much like that observed in development of antiphase (martensitic) structures. Martensitic transformations in U, Np, and Pu, from high-temperature b. c. c. to alpha phase, may be a way of ordering an alloy-like metal of mixed or intermediate valence. The relative stability of each phase structure may depend upon its electron-valence ratio. A Hubbard model for electron correlations in a narrow energy band has been invoked in most recent theories for explaining light actinide behavior. Such a model may also be applicable to crystal symmetry changes in martensitic transformations in actinides

Valencies of the lanthanides

OpenAIRE

Johnson, David A.; Nelson, Peter G.

2018-01-01

The valencies of the lanthanides vary more than was once thought. In addition to valencies associated with a half-full shell, there are valencies associated with a quarter- and three-quarter-full shell. This can be explained on the basis of Slater’s theory of many-electron atoms. The same theory explains the variation in complexing constants in the trivalent state (the “tetrad effect”). Valency in metallic and organometallic compounds is also discussed.

Valence and Magnetic Transitions in YbMn2Ge2-Applied Pressure

International Nuclear Information System (INIS)

Hofmann, M.; Link, P.; Campbell, S.J.; Goncharenko, I.

2005-01-01

Full text: Rare-earth intermetallic compounds containing ytterbium exhibit a wide range of interesting and unusual physical and magnetic properties. This occurs mainly as a result of their mixed valence states (II/III) or changes from one valence state to the other. We have recently determined the magnetic structures of tetragonal YbMn 2 Ge 2 (I4/mmm) by powder neutron diffraction experiments and demonstrated that YbMn 2 Ge 2 has a planar antiferromagnetic structure below T N1 ∼ 510 K with a canted antiferromagnetic structure below T N2 ∼ 185 K. As applied pressure favours changes in the valence character of intermediate valence systems and correspondingly influences the magnetic behaviour, we have investigated the effects of applied pressure on YbMn 2 Ge 2 . Analyses of our in situ neutron diffraction experiments (T=1.5-300 K; p=0-2.7 GPa), reveal a distinct change in magnetic structure and a sharp drop in the a-lattice parameter above ∼ 1.4 GPa with the changes associated with a valence transition. A full account of these effects will be discussed in relation to our current photoelectron spectroscopy measurements of YbMn 2 Ge 2 . (authors)

Valence effects of sorption: laboratory control of valence state

International Nuclear Information System (INIS)

Meyer, R.E.; Arnold, W.D.; Case, F.I.

1984-01-01

Estimation of the rates of migration of nuclides from nuclear waste repositories required knowledge of the interaction of these nuclides with the components of the geological formations in the path of the migration. These interactions will be dependent upon the valence state and speciation of the nuclide. If the valence state is not known, then there can be little confidence in use of the data for safety analysis. An electrochemical method of valence state control was developed which makes use of a porous electrode in a flow system containing a column of the adsorbent. By use of this method and solvent extraction analyses of the valence states, a number of reactions of interest to HLW repositories were investigated. These include the reduction of Np(V) and Tc(VII) by crushed basalt and other minerals. For the reduction of Np(V) by basalt, the experiments indicate that sorption on basalt increases with pH and that most of the Np is reduced to Np(IV). The adsorbed Np(IV) is very difficult to remove from the basalt. For the experiments with Tc(VII), the results are considerably more complicated. The results of these experiments are used to assess some of the techniques and methods currently used in safety analyses of proposed HLW repositories. Perhaps the most important consideration is that predictive modeling of valence change reactions, such as the reduction of Np(V) and Tc(VII), must be used with considerable caution, and the occurrence of such reactions should be verified as best as possible with experiments using valence state control and analyses. 13 references, 3 figures, 1 table

But for the Bad, There Would Not Be Good: Grounding Valence in Brightness through Shared Relational Structures

Science.gov (United States)

Lakens, Daniel; Semin, Gun R.; Foroni, Francesco

2012-01-01

Light and dark are used pervasively to represent positive and negative concepts. Recent studies suggest that black and white stimuli are automatically associated with negativity and positivity. However, structural factors in experimental designs, such as the shared opposition in the valence (good vs. bad) and brightness (light vs. dark) dimensions…

Importance-truncated shell model for multi-shell valence spaces

Energy Technology Data Exchange (ETDEWEB)

Stumpf, Christina; Vobig, Klaus; Roth, Robert [Institut fuer Kernphysik, TU Darmstadt (Germany)

2016-07-01

The valence-space shell model is one of the work horses in nuclear structure theory. In traditional applications, shell-model calculations are carried out using effective interactions constructed in a phenomenological framework for rather small valence spaces, typically spanned by one major shell. We improve on this traditional approach addressing two main aspects. First, we use new effective interactions derived in an ab initio approach and, thus, establish a connection to the underlying nuclear interaction providing access to single- and multi-shell valence spaces. Second, we extend the shell model to larger valence spaces by applying an importance-truncation scheme based on a perturbative importance measure. In this way, we reduce the model space to the relevant basis states for the description of a few target eigenstates and solve the eigenvalue problem in this physics-driven truncated model space. In particular multi-shell valence spaces are not tractable otherwise. We combine the importance-truncated shell model with refined extrapolation schemes to approximately recover the exact result. We present first results obtained in the importance-truncated shell model with the newly derived ab initio effective interactions for multi-shell valence spaces, e.g., the sdpf shell.

Semiempirical search for oxide superconductors based on bond valence sums

International Nuclear Information System (INIS)

Tanaka, S.; Fukushima, N.; Niu, H.; Ando, K.

1992-01-01

Relationships between crystal structures and electronic states of layered transition-metal oxides are analyzed in the light of bond valence sums. Correlations between the superconducting transition temperature T c and the bond-valence-sum parameters are investigated for the high-T c cuprate compounds. Possibility of making nonsuperconducting oxides superconducting is discussed. (orig.)

Hole energy and momentum distributions in valence bands

International Nuclear Information System (INIS)

Laan, G. van der.

1982-01-01

In order to understand the electrical and magnetic properties of solids, the knowledge of the density of states and the dispersion relation of the valence bands is indispensable. This thesis offers some alternative methods to obtain information about the nature of the valence band. Part A deals with the energy distribution of the photoelectrons. A simple model, which explains the core hole satellite structure in compounds with large correlation effects between the valence band holes and the created photo-hole, is outlined. CuCl, CuX 2 (X = F Cl and Br) are studied, by photoemission and Auger electron spectroscopies in determining the valence band properties. Part B deals with the simultaneous measurement of the energy and the wave vector of the emitted electrons. A practical example is given for the determination of the dispersion relation in copper. The measurements of a surface resonance band and the distribution of the secondary electrons are also reported. (Auth.)

Effect of valence on the electromigration in silver

International Nuclear Information System (INIS)

Nguyen Van Doan

1970-01-01

It is shown that the apparent effective valence Z B ** of a solute deduced from experiments differs from the true effective valence Z B * defined in the atomic models by a corrective term due to the 'vacancy flow effect'. The experimental results suggest that this corrective term is very important and that it is negative for transition elements; this hypothesis is confirmed for the case of iron in a copper matrix. For the elements to the right of silver in the periodic table, where the correction can be neglected, the effective valence of the solute varies linearly with z (z + 1), z being the difference between the valency of the solute and the solvent; in contrast, the further the solute is from the solvent in the periodic table the more nearly the electronic structure of the ion at the saddle point resembles that of the ion at the equilibrium position. (author) [fr

Brain activations to emotional pictures are differentially associated with valence and arousal ratings

Directory of Open Access Journals (Sweden)

Antje B M Gerdes

2010-10-01

Full Text Available Several studies have investigated the neural responses triggered by emotional pictures, but the specificity of the involved structures such as the amygdala or the ventral striatum is still under debate. Furthermore, only few studies examined the association of stimuli’s valence and arousal and the underlying brain responses. Therefore, we investigated brain responses with functional magnetic resonance imaging of 17 healthy subjects to pleasant and unpleasant affective pictures with comparable arousal levels and afterwards assessed ratings of valence and arousal. As expected, unpleasant pictures strongly activated the right and left amygdala, the right hippocampus, and the medial occipital lobe, whereas pleasant pictures elicited significant activations in left occipital regions, and in parts of the medial temporal lobe. The direct comparison of unpleasant and pleasant pictures which were comparable in arousal clearly indicated stronger amygdala activation in response to the unpleasant pictures. Most important, correlational analyses revealed on the one hand that the arousal of unpleasant pictures was significantly associated with activations in the right amygdala and the left caudate body. On the other hand, valence of pleasant pictures was significantly correlated with activations in the right caudate head, extending to the nucleus accumbens (NAcc and the left dorso-lateral prefrontal cortex. These findings support the notion that the amygdala is primarily involved in processing of unpleasant stimuli, and the stronger the more arousing the stimuli are, whereas reward-related structures like the NAcc primarily responds to pleasant stimuli, the stronger the more positive the valence of these stimuli is.

Polarization Dependent Bulk-sensitive Valence Band Photoemission Spectroscopy and Density Functional Theory Calculations: Part I. 3d Transition Metals

Science.gov (United States)

Ueda, Shigenori; Hamada, Ikutaro

2017-12-01

The X-ray polarization dependent valence band HAXPES spectra of 3d transition metals (TMs) of Ti-Zn were measured to investigate the orbital resolved electronic structures by utilizing that the fact the photoionization cross-section of the atomic orbitals strongly depends on the experimental geometry. We have calculated the HAXPES spectra, which correspond to the cross-section weighted densities of states (CSW-DOSs), where the DOSs were obtained by the density functional theory calculations, and we have determined the relative photoionization cross-sections of the 4s and 4p orbitals to the 3d orbital in the 3d TMs. The experimentally obtained bulk-sensitive 3d and 4s DOSs were good agreement with the calculated DOSs in Ti, V, Cr, and Cu. In contrast, the deviations between the experimental and calculated 3d DOSs for Mn, Fe, Co, Ni were found, suggesting that the electron correlation plays an important role in the electronic structures for these materials.

Covariant boost and structure functions of baryons in Gross-Neveu models

International Nuclear Information System (INIS)

Brendel, Wieland; Thies, Michael

2010-01-01

Baryons in the large N limit of two-dimensional Gross-Neveu models are reconsidered. The time-dependent Dirac-Hartree-Fock approach is used to boost a baryon to any inertial frame and shown to yield the covariant energy-momentum relation. Momentum distributions are computed exactly in arbitrary frames and used to interpolate between the rest frame and the infinite momentum frame, where they are related to structure functions. Effects from the Dirac sea depend sensitively on the occupation fraction of the valence level and the bare fermion mass and do not vanish at infinite momentum. In the case of the kink baryon, they even lead to divergent quark and antiquark structure functions at x=0.

Pion and kaon valence-quark parton quasidistributions

Science.gov (United States)

Xu, Shu-Sheng; Chang, Lei; Roberts, Craig D.; Zong, Hong-Shi

2018-05-01

Algebraic Ansätze for the Poincaré-covariant Bethe-Salpeter wave functions of the pion and kaon are used to calculate their light-front wave functions, parton distribution amplitudes, parton quasidistribution amplitudes, valence parton distribution functions, and parton quasidistribution functions (PqDFs). The light-front wave functions are broad, concave functions, and the scale of flavor-symmetry violation in the kaon is roughly 15%, being set by the ratio of emergent masses in the s - and u -quark sectors. Parton quasidistribution amplitudes computed with longitudinal momentum Pz=1.75 GeV provide a semiquantitatively accurate representation of the objective parton distribution amplitude, but even with Pz=3 GeV , they cannot provide information about this amplitude's end point behavior. On the valence-quark domain, similar outcomes characterize PqDFs. In this connection, however, the ratio of kaon-to-pion u -quark PqDFs is found to provide a good approximation to the true parton distribution function ratio on 0.4 ≲x ≲0.8 , suggesting that with existing resources computations of ratios of parton quasidistributions can yield results that support empirical comparison.

Unpolarized structure functions and the parton distributions for nucleon in an independent quark model

Energy Technology Data Exchange (ETDEWEB)

Barik, N [Dept. of Physics, Utkal Univ., Bhubaneswar (India); Mishra, R N [Dept. of Physics, Dhenkanal College, Dhenkanal (India)

2001-04-01

Considering the nucleon as consisting entirely of its valence quarks confined independently in a scalar-vector harmonic potential; unpolarized structure functions F{sub 1} (x, {mu}{sup 2}) and F{sub 2} (x, {mu}{sup 2}) are derived in the Bjorken limit under certain simplifying assumptions; from which valence quark distribution functions u{sub v} (x, {mu}{sup 2}) and d{sub v} (x, {mu}{sup 2}) are appropriately extracted satisfying the normalization constraints. QCD-evolution of these input distributions from a model scale of {mu}{sup 2} = 0.07 GeV{sup 2} to a higher Q{sup 2} scale of Q{sub 0}{sup 2} = 15 GeV{sup 2} yields xu{sub v} (x, Q{sub 0}{sup 2}) and xd{sub v} (x, Q{sub 0}{sup 2}) in good agreement with experimental data. The gluon and sea-quark distributions such as G (x, Q{sub 0}{sup 2}) and q{sub s} (x, Q{sub 0}{sup 2}) are dynamically generated with a reasonable qualitative agreement with the available data; using the leading order renormalization group equations with appropriate valence-quark distributions as the input. (author)

Electronic structure of SnF{sub 3}: An example of valence skipper which forms charge density wave

Energy Technology Data Exchange (ETDEWEB)

Hase, I., E-mail: i.hase@aist.go.jp [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568 (Japan); Yanagisawa, T. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8568 (Japan); Kawashima, K. [IMRA Material R& D Co., LTD., Kariya, Aichi 448-0032 (Japan)

2016-11-15

Highlights: • We calculated the electronic structure of SnF{sub 3} and BaBiO{sub 3} from first principles. • As for SnF{sub 3}, charge-density-wave (CDW) is found, which agrees with the experiment. • As for BaBiO{sub 3}, CDW is not found, contrary to the experiment. • We conclude that the CDW is hard in SnF{sub 3} and is soft in BaBiO{sub 3}. - Abstract: In the present study we calculated the electronic structure of the valence skipping compound SnF{sub 3} and BaBiO{sub 3} from first-principles. We confirmed that the charge-density-wave (CDW) is formed in SnF{sub 3}, and the Sn atoms in two crystallographic different sites take the valence Sn{sup 2+} and Sn{sup 4+}. Structure optimization study reveals that this CDW is stable, though the atomic position is slightly different from the experimental data. This behavior is in contrast with the case of BaBiO{sub 3}, where the structure optimization leads to the uniform state, which means that two Bi sites are equivalent. The CDW state is hard in SnF{sub 3}, which means that the CDW gap is large enough and it is difficult to melt this CDW order.

QCD's Partner Needed for Mass Spectra and Parton Structure Functions

International Nuclear Information System (INIS)

Kim, Y.S.

2009-01-01

as in the case of the hydrogen atom, bound-state wave functions are needed to generate hadronic spectra. For this purpose, in 1971, Feynman and his students wrote down a Lorentz-invariant harmonic oscillator equation. This differential equation has one set of solutions satisfying the Lorentz-covariant boundary condition. This covariant set generates Lorentz-invariant mass spectra with their degeneracies. Furthermore, the Lorentz-covariant wave functions allow us to calculate the valence parton distribution by Lorentz-boosting the quark-model wave function from the hadronic rest frame. However, this boosted wave function does not give an accurate parton distribution. The wave function needs QCD corrections to make a contact with the real world. Likewise, QCD needs the wave function as a starting point for calculating the parton structure function. (author)

Valence-to-core-detected X-ray absorption spectroscopy

DEFF Research Database (Denmark)

Hall, Eleanor R.; Pollock, Christopher J.; Bendix, Jesper

2014-01-01

X-ray absorption spectroscopy (XAS) can provide detailed insight into the electronic and geometric structures of transition-metal active sites in metalloproteins and chemical catalysts. However, standard XAS spectra inherently represent an average contribution from the entire coordination...... environment with limited ligand selectivity. To address this limitation, we have investigated the enhancement of XAS features using valence-to-core (VtC)-detected XAS, whereby XAS spectra are measured by monitoring fluorescence from valence-to-core X-ray emission (VtC XES) events. VtC emission corresponds...... to transitions from filled ligand orbitals to the metal 1s core hole, with distinct energetic shifts for ligands of differing ionization potentials. VtC-detected XAS data were obtained from multiple valence emission features for a series of well-characterized Mn model compounds; taken together, these data...

Excitations of one-valence-proton, one-valence-neutron nucleus {sup 210}Bi from cold-neutron capture

Energy Technology Data Exchange (ETDEWEB)

Cieplicka-Oryńczak, N. [INFN sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Kraków (Poland); Fornal, B.; Szpak, B. [Institute of Nuclear Physics, Polish Academy of Sciences, PL-31342 Kraków (Poland); Leoni, S.; Bottoni, S. [INFN sezione di Milano, Via Celoria 16, 20133 Milano (Italy); Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); Bazzacco, D. [Dipartimento di Fisica e Astronomia dell’Università, I-35131 Padova (Italy); INFN Sezione di Padova, I-35131 Padova (Italy); Blanc, A.; Jentschel, M.; Köster, U.; Mutti, P.; Soldner, T. [Institute Laue-Langevin, 6, rue Jules Horowitz, 38042 Grenoble Cedex 9 (France); Bocchi, G. [Università degli Studi di Milano, Via Celoria 16, 20133 Milano (Italy); France, G. de [GANIL, Bd. Becquerel, BP 55027, 14076 CAEN Cedex 05 (France); Simpson, G. [LPSC, Université Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut National Polytechnique de Grenoble, F-38026 Grenoble Cedex (France); Ur, C. [INFN Sezione di Padova, Via F. Marzolo 8, I-35131 Padova (Italy); Urban, W. [Faculty of Physics, University of Warsaw, ul. Hoża 69, 02-681, Warszawa (Poland)

2015-10-15

The low-spin structure of one-proton, one-neutron {sup 210}Bi nucleus was investigated in cold-neutron capture reaction on {sup 209}Bi. The γ-coincidence measurements were performed with use of EXILL array consisted of 16 HPGe detectors. The experimental results were compared to shell-model calculations involving valence particles excitations. The {sup 210}Bi nucleus offers the potential to test the effective proton-neutron interactions because most of the states should arise from the proton-neutron excitations. Additionally, it was discovered that a few states should come from the couplings of valence particles to the 3{sup −} octupole vibration in {sup 208}Pb which provides also the possibility of testing the calculations involving the core excitations.

Simulating Valence-to-Core X-ray Emission Spectroscopy of Transition Metal Complexes with Time-Dependent Density Functional Theory.

Science.gov (United States)

Zhang, Yu; Mukamel, Shaul; Khalil, Munira; Govind, Niranjan

2015-12-08

Valence-to-core (VtC) X-ray emission spectroscopy (XES) has emerged as a powerful technique for the structural characterization of complex organometallic compounds in realistic environments. Since the spectrum represents electronic transitions from the ligand molecular orbitals to the core holes of the metal centers, the approach is more chemically sensitive to the metal-ligand bonding character compared with conventional X-ray absorption techniques. In this paper we study how linear-response time-dependent density functional theory (LR-TDDFT) can be harnessed to simulate K-edge VtC X-ray emission spectra reliably. LR-TDDFT allows one to go beyond the single-particle picture that has been extensively used to simulate VtC-XES. We consider seven low- and high-spin model complexes involving chromium, manganese, and iron transition metal centers. Our results are in good agreement with experiment.

Field-induced valence transition in rare-earth system

International Nuclear Information System (INIS)

Chattopadhaya, A.; Ghatak, S.K.

2000-01-01

The magnetic field-induced valence transition in rare-earth compound has been examined based on a pseudospin S=1 Ising model proposed earlier for valence transition. The model includes finite mixing between two pertinent ionic configurations (magnetic and non-magnetic) separated by an energy gap and with intersite interaction between rare-earth ions. Using the mean field approximation the magnetic behaviour and the critical field (H c ) for transition are obtained as a function of energy gap and temperature. The phase boundary defined in terms of reduced field H c /H co and reduced temperature T/T v (T v being valence transition temperature in absence of field) is nearly independent of energy gap. These results are in qualitative agreement with experimental observation in Yb- and Eu-compounds

Valence and non-valence quark distribution function of hadrons in the val on model

International Nuclear Information System (INIS)

Khorramian, A.N.; Arash, F.

2000-01-01

We calculate the par tonic structure of constitute quark in the next-to-leading order. The structure of any hadron can be obtained thereafter using a convolution method. Such a procedure is used to generate the structure function of proton and pion in Next- to- leading order

Features of carrier tunneling between the silicon valence band and metal in devices based on the Al/high-K oxide/SiO_2/Si structure

International Nuclear Information System (INIS)

Vexler, M. I.; Grekhov, I. V.

2016-01-01

The features of electron tunneling from or into the silicon valence band in a metal–insulator–semiconductor system with the HfO_2(ZrO_2)/SiO_2 double-layer insulator are theoretically analyzed for different modes. It is demonstrated that the valence-band current plays a less important role in structures with HfO_2(ZrO_2)/SiO_2 than in structures containing only silicon dioxide. In the case of a very wide-gap high-K oxide ZrO_2, nonmonotonic behavior related to tunneling through the upper barrier is predicted for the valence-band–metal current component. The use of an insulator stack can offer certain advantages for some devices, including diodes, bipolar tunnel-emitter transistors, and resonant-tunneling diodes, along with the traditional use of high-K insulators in a field-effect transistor.

Structure function of off-mass-shell pions and the calculation of the Sullivan process

International Nuclear Information System (INIS)

Shakin, C.M.; Sun, W.

1994-01-01

We construct a model for the pion (valence) structure function that fits the experimental data obtained in the study of the Drell-Yan process. The model may also be used to calculate the structure function of off-mass-shell pions. We apply our model in the study of deep-inelastic scattering from off-mass-shell pions found in the nucleon and are thus able to resolve a problem encountered in the standard analysis of such processes. The usual analysis is made using the structure function of on-mass-shell pions and requires the use of a soft πNN form factor that is inconsistent with standard nuclear physics phenomenology. The use of our off-mass-shell structure functions allows for a fit to the data for nonperturbative aspects of the nucleon ''sea'' with a pion-nucleon form factor of the standard form

The electronic fine structure of 4-nitrophenyl functionalized single-walled carbon nanotubes

International Nuclear Information System (INIS)

Chakraborty, Amit K; Coleman, Karl S; Dhanak, Vinod R

2009-01-01

Controlling the electronic structure of carbon nanotubes (CNTs) is of great importance to various CNT based applications. Herein the electronic fine structure of single-walled carbon nanotube films modified with 4-nitrophenyl groups, produced following reaction with 4-nitrobenzenediazonium tetrafluoroborate, was investigated for the first time. Various techniques such as x-ray and ultra-violet photoelectron spectroscopy, and near edge x-ray absorption fine structure studies were used to explore the electronic structure, and the results were compared with the measured electrical resistances. A reduction in number of the π electronic states in the valence band consistent with the increased resistance of the functionalized nanotube films was observed.

Oxygen Evolution at Manganite Perovskite Ruddlesden-Popper Type Particles: Trends of Activity on Structure, Valence and Covalence

Directory of Open Access Journals (Sweden)

Majid Ebrahimizadeh Abrishami

2016-11-01

Full Text Available An improved understanding of the correlation between the electronic properties of Mn-O bonds, activity and stability of electro-catalysts for the oxygen evolution reaction (OER is of great importance for an improved catalyst design. Here, an in-depth study of the relation between lattice structure, electronic properties and catalyst performance of the perovskite Ca1−xPrxMnO3 and the first-order RP-system Ca2−xPrxMnO4 at doping levels of x = 0, 0.25 and 0.5 is presented. Lattice structure is determined by X-ray powder diffraction and Rietveld refinement. X-ray absorption spectroscopy of Mn-L and O-K edges gives access to Mn valence and covalency of the Mn-O bond. Oxygen evolution activity and stability is measured by rotating ring disc electrode studies. We demonstrate that the highest activity and stability coincidences for systems with a Mn-valence state of +3.7, though also requiring that the covalency of the Mn-O bond has a relative minimum. This observation points to an oxygen evolution mechanism with high redox activity of Mn. Covalency should be large enough for facile electron transfer from adsorbed oxygen species to the MnO6 network; however, it should not be hampered by oxidation of the lattice oxygen, which might cause a crossover to material degradation. Since valence and covalency changes are not entirely independent, the introduction of the energy position of the eg↑ pre-edge peak in the O-K spectra as a new descriptor for oxygen evolution is suggested, leading to a volcano-like representation of the OER activity.

Automated Construction of Molecular Active Spaces from Atomic Valence Orbitals.

Science.gov (United States)

Sayfutyarova, Elvira R; Sun, Qiming; Chan, Garnet Kin-Lic; Knizia, Gerald

2017-09-12

We introduce the atomic valence active space (AVAS), a simple and well-defined automated technique for constructing active orbital spaces for use in multiconfiguration and multireference (MR) electronic structure calculations. Concretely, the technique constructs active molecular orbitals capable of describing all relevant electronic configurations emerging from a targeted set of atomic valence orbitals (e.g., the metal d orbitals in a coordination complex). This is achieved via a linear transformation of the occupied and unoccupied orbital spaces from an easily obtainable single-reference wave function (such as from a Hartree-Fock or Kohn-Sham calculations) based on projectors to targeted atomic valence orbitals. We discuss the premises, theory, and implementation of the idea, and several of its variations are tested. To investigate the performance and accuracy, we calculate the excitation energies for various transition-metal complexes in typical application scenarios. Additionally, we follow the homolytic bond breaking process of a Fenton reaction along its reaction coordinate. While the described AVAS technique is not a universal solution to the active space problem, its premises are fulfilled in many application scenarios of transition-metal chemistry and bond dissociation processes. In these cases the technique makes MR calculations easier to execute, easier to reproduce by any user, and simplifies the determination of the appropriate size of the active space required for accurate results.

Valence states of cobalt and crystal structure peculiarities of solid solution YBa2Cu3-xCoxO6+σ

International Nuclear Information System (INIS)

Voronin, V.I.; Goshchinskij, B.N.; Mitberg, Eh.B.; Leonidov, I.A.; Kozhevnikov, V.L.

2000-01-01

Crystal structure of solid solution YBa 2 Cu 3-x Co x O 6+σ , where x = 0.2, 0.4, 0.6 and 0.8, is studied by the method of powder neutron diffraction. Charge states of the cation are calculated using the interatomic distances obtained. It is shown that cobalt in Cu1 position has valency 3 + and octahedral coordination at x = 0.2 and 0.4. Increase in doping degree involves both transition of a portion of cobalt ions in the positions mentioned to the state with valence 4 + and tetrahedral coordination and partial substitution of copper in Cu2 position [ru

Praseodymium valency from crystal structure in Pr-Ba-Cu-O and (Y-Pr)-Ba-Cu-O single crystals

International Nuclear Information System (INIS)

Collin, G.; Albouy, P.A.; Monod, P.; Ribault, M.

1990-01-01

The substitution of Pr to Y leads to materials with a general formula (Y 1-v Pr v ) (Ba 2-x Pr x ) (Cu 3-y vac y ) O 6+x/2-y+z and with a structural transition around v + x' ∼ 0.5. For v + x 0.5 the crystals are tetragonal, La 1.5 Ba 1.5 Cu 3 O 7±z type, with the characteristic tri-twinning of this phase. The Pr valency, in the range 3-3.2 + depending on preparation conditions, is determined from interatomic distances. Orthorhombic crystals of Pr Ba Cu O prepared at high temperatures exhibit a high amount of defects, y ∼ 0.25 on the Cu(1) site and are semiconductors with a T -1/4 activation law attributed to the praseodymium valence fluctuation

Relaxation and cross section effects in valence band photoemission spectroscopy

International Nuclear Information System (INIS)

McFeely, F.R.

1976-09-01

Various problems relating to the interpretation of valence band x-ray photoemission (XPS) spectra of solids are discussed. The experiments and calculations reported herein deal with the following questions: (1) To what extent do many-body effects manifest themselves in an XPS valence band spectrum, and thus invalidate a direct comparison between the photoemission energy distribution, I(E), and the density of states, N(E), calculated on the basis of ground-state one-electron theory. (2) The effect of the binding-energy-dependent photoemission cross section on I(E) at XPS energies. (3) In favorable cases indicated by (1) and (2) we examine the effect of the interaction of the crystal field with the apparent spin-orbit splittings of core levels observed in XPS spectra. (4) The use of tight binding band structure calculations to parameterize the electronic band structure from XPS and other data is described. (5) The use of high energy angle-resolved photoemission on oriented single crystals to gain orbital symmetry information is discussed. (6) The evolution of the shape of the photoemission energy distribution (of polycrystalline Cu) as a function of photon energy from 50 less than or equal h ω less than or equal 175 is discussed

Optoelectronic properties of valence-state-controlled amorphous niobium oxide

Science.gov (United States)

Onozato, Takaki; Katase, Takayoshi; Yamamoto, Akira; Katayama, Shota; Matsushima, Koichi; Itagaki, Naho; Yoshida, Hisao; Ohta, Hiromichi

2016-06-01

In order to understand the optoelectronic properties of amorphous niobium oxide (a-NbO x ), we have investigated the valence states, local structures, electrical resistivity, and optical absorption of a-NbO x thin films with various oxygen contents. It was found that the valence states of Nb ion in a-NbO x films can be controlled from 5+  to 4+  by reducing oxygen pressure during film deposition at room temperature, together with changing the oxide-ion arrangement around Nb ion from Nb2O5-like to NbO2-like local structure. As a result, a four orders of magnitude reduction in the electrical resistivity of a-NbO x films was observed with decreasing oxygen content, due to the carrier generation caused by the appearance and increase of an oxygen-vacancy-related subgap state working as an electron donor. The tunable optoelectronic properties of a-NbO x films by valence-state-control with oxygen-vacancy formation will be useful for potential flexible optoelectronic device applications.

Valence-delocalization of the mixed-valence oxo-centered trinuclear iron propionates [FeIII2FeIIO(C2H5CO2)6(py)3[npy; n = 0, 1.5

International Nuclear Information System (INIS)

Nakamoto, Tadahiro; Katada, Motomi; Kawata, Satoshi; Kitagawa, Susumu; Sano, Hirotoshi; Konno, Michiko

1994-01-01

Mixed-valence trinuclear iron propionates [Fe III 2 Fe II O(C 2 H 5 CO 2 ) 6 (py) 3 [npy, where n = 0, 1.5, were synthesized and the structure of the pyridine-solvated complex was determined by single-crystal X-ray diffraction. Moessbauer spectra of the solvated propionate complex showed a temperature-dependent mixed-valence state related to phase transitions, reaching an almost delocalized valence state at room temperature. On the other hand, the non-solvated propionate showed a remarkable change of the spectral shape related to a phase transition, remaining in a localized valence state at higher temperatures up to room temperature. (orig.)

Quatenary structure of methemoglobin II. Pulse radiolysis study of the binding of oxygen to the valence-hybrid. Progress report, December 1, 1978-November 30, 1979

International Nuclear Information System (INIS)

Chevion, M.; Ilan, Y.A.; Samuni, A.; Navok, T.; Czapski, G.

1979-01-01

The pulse-radiolysis of solutions of adult human methemoglobin was used in order to reduce a single heme-iron within the protein tetramers. The valence-hybrids thus formed were reacted with oxygen. Kinetics of the reactions were studied. The effects of pH and inositol-hexaphosphate were examined. The kinetics of the ligation of oxygen to stripped valence-hybrids showed a single-phase behavior at the pH range 6.5 to 9. As the pH was lowered below 6.5 a second, slower phase became apparent. In the presence of IHP, above pH 8, the kinetics of oxygem binding was of a single phase. As the pH was lowered a transition to a second, slower phase was noticed. Below pH 7 the slower phase was the only detectable one. The analysis of the relative contribution of the faster phase to the total reaction as a function of the pH showed a typical transition curve characterized by a pK = 7.5 and a Hill parameter n =2.9. On the basis it is concluded that human adult stripped methemoglobin resides in an R quarternary structure while the presence of IHP stabilizes the T structure at pH below 7.5

Effects of crystal structure and composition on the photocatalytic performance of Ta-O-N functional materials.

Science.gov (United States)

Liu, Qing-Lu; Zhao, Zong-Yan; Yi, Jian-Hong

2018-05-07

For photocatalytic applications, the response of a material to the solar spectrum and its redox capabilities are two important factors determined by the band gap and band edge position of the electronic structure of the material. The crystal structure and composition of the photocatalyst are fundamental for determining the above factors. In this article, we examine the functional material Ta-O-N as an example of how to discuss relationships among these factors in detail with the use of theoretical calculations. To explore how the crystal structure and composition influence the photocatalytic performance, two groups of Ta-O-N materials were considered: the first group included ε-Ta 2 O 5 , TaON, and Ta 3 N 5 ; the second group included β-Ta 2 O 5 , δ-Ta 2 O 5 , ε-Ta 2 O 5 , and amorphous-Ta 2 O 5 . Calculation results indicated that the band gap and band edge position are determined by interactions between the atomic core and valence electrons, the overlap of valence electronic states, and the localization of valence states. Ta 3 N 5 and TaON are suitable candidates for efficient photocatalysts owing to their photocatalytic water-splitting ability and good utilization efficiency of solar energy. δ-Ta 2 O 5 has a strong oxidation potential and a band gap suitable for absorbing visible light. Thus, it can be applied to photocatalytic degradation of most pollutants. Although a-Ta 2 O 5 , ε-Ta 2 O 5 , and β-Ta 2 O 5 cannot be directly used as photocatalysts, they can still be applied to modify conventional Ta-O-N photocatalysts, owing to their similar composition and structure. These calculation results will be helpful as reference data for analyzing the photocatalytic performance of more complicated Ta-O-N functional materials. On the basis of these findings, one could design novel Ta-O-N functional materials for specific photocatalytic applications by tuning the composition and crystal structure.

Intermediate valence spectroscopy

International Nuclear Information System (INIS)

Gunnarsson, O.; Schoenhammer, K.

1987-01-01

Spectroscopic properties of intermediate valence compounds are studied using the Anderson model. Due to the large orbital and spin degeneracy N/sub f/ of the 4f-level, 1/N/sub f/ can be treated as a small parameter. This approach provides exact T = 0 results for the Anderson impurity model in the limit N/sub f/ → ∞, and by adding 1/N/sub f/ corrections some properties can be calculated accurately even for N/sub f/ = 1 or 2. In particular valence photoemission and resonance photoemission spectroscopies are studied. A comparison of theoretical and experimental spectra provides an estimate of the parameters in the model. Core level photoemission spectra provide estimates of the coupling between the f-level and the conduction states and of the f-level occupancy. With these parameters the model gives a fair description of other electron spectroscopies. For typical parameters the model predicts two structures in the f-spectrum, namely one structure at the f-level and one at the Fermi energy. The resonance photoemission calculation gives a photon energy dependence for these two peaks in fair agreement with experiment. The peak at the Fermi energy is partly due to a narrow Kondo resonance, resulting from many-body effects and the presence of a continuous, partly filled conduction band. This resonance is related to a large density of low-lying excitations, which explains the large susceptibility and specific heat observed for these systems at low temperatures. 38 references, 11 figures, 2 tables

Optical verification of the valence band structure of cadmium arsenide

NARCIS (Netherlands)

Gelten, M.J.; Es, van C.M.; Blom, F.A.P.; Jongeneelen, J.W.F.

1980-01-01

Optical absorption measurements were performed on thin single crystalline samples of Cd3As2 at temperatures of 300 K and 10 K. At low temperature the interband absorption coefficient shows clearly two steps due to direct transitions from the heavy hole and light hole valence bands to the conduction

Valence shell photoionization energies and cross-sections of NF sub 3 and PF sub 3

CERN Document Server

Jürgensen, A

2003-01-01

Relative outer valence shell ionization potentials and cross-sections were determined for the isostructural, Group 15, trifluorides NF sub 3 and PF sub 3 in the gas phase using synchrotron radiation. Excitation photon energies ranged from 70 to 160 eV. The experimental spectra were assigned and cross-sections analyzed with the aid of both MS-X alpha and ab initio calculations. Spectral differences in peak energies and relative intensities are related to structural and electronic differences between these two fluoride molecules. Valence shell ionization potentials were compared to calculated values obtained by several different methods. The partial photoionization cross-sections for each orbital were obtained as a function of excitation energy and compared to theoretical results obtained with the X alpha method.

Core and valence level photoemission and photoabsorption study of icosahedral Al-Pd-Mn quasicrystals

International Nuclear Information System (INIS)

Horn, K; Theis, W; Paggel, J J; Barman, S R; Rotenberg, E; Ebert, Ph; Urban, K

2006-01-01

The electronic structure of quasicrystalline Al-Pd-Mn is investigated by means of valence and core level photoelectron spectroscopy. Variations of the photoionization cross section in the constituents' valence electronic levels as a function of photon energy are used to identify contributions from the different atomic species, in particular near the Pd 4d Cooper minimum. Resonant photoemission at the Mn 2p absorption edge shows the contribution of the Mn 3d states to the density of states in a region near the Fermi level. The asymmetry of Pd 3d and Mn 2p core level photoemission lines, and its difference for emission from metallic and quasicrystalline phases, are utilized to infer the contributions of the different constituents to the density of states at the Fermi level

Density functional study of electronic structure, elastic and optical properties of MNH2 (M=Li, Na, K, Rb)

International Nuclear Information System (INIS)

Babu, K Ramesh; Vaitheeswaran, G

2014-01-01

We report a systematic first principles density functional study on the electronic structure, elastic and optical properties of nitrogen based solid hydrogen storage materials LiNH 2 , NaNH 2 , KNH 2 , and RbNH 2 . The ground state structural properties are calculated by using standard density functional theory, and also dispersion corrected density functional theory. We find that van der Waals interactions are dominant in LiNH 2 whereas they are relatively weak in other alkali metal amides. The calculated elastic constants show that all the compounds are mechanically stable and LiNH 2 is found to be a stiffer material among the alkali metal amides. The melting temperatures are calculated and follow the order RbNH 2 2 2 2 . The electronic band structure is calculated by using the Tran–Blaha modified Becke–Johnson potential and found that all the compounds are insulators, with a considerable band gap. The [NH 2 ] − derived states completely dominate in the entire valence band region while the metal atom states occupy the conduction band. The calculated band structure is used to analyze the different interband optical transitions occurring between valence and conduction bands. Our calculations show that these materials have considerable optical anisotropy. (paper)

Valence determination as a function of doping in $PrBa_{2} Cu_{3} O_{7}$

CERN Document Server

Staub, U; Wasserman, S R; Conner, A G O; Kramer, M J; Patterson, B D; Shi, M; Knapp, M P

2000-01-01

We present results of X-ray absorption near edge spectra (XANES), neutron powder diffraction, and resonant X-ray diffraction on samples of PrBa/sub 2/Cu/sub 3/O/sub 7- delta / and Pr/sub 1-x/Ca/sub x/Ba /sub 2/Cu/sub 3/O/sub 7/. The data are obtained as a function of the doping levels of oxygen and Ca. There are significant changes in the Pr L/sub 3/ XANES spectra with changes in oxygen or Ca concentrations, indicating that the Pr electronic properties are affected by doping. The resonant X-ray scattering experiments show that the changes observed occur on Pr ions incorporated in the PrBa /sub 2/Cu/sub 3/O/sub 7- delta / structure, and are not the result of changes to a Pr-containing impurity phase. A quantitative model, based on literature precedent, is used to extract Pr valences from the data, although the XANES cannot distinguish between models involving charge transfer and those involving hybridization. The results are compared with data obtained from Pb/sub 2/Sr/sub 2/Pr/sub 1-x/Ca/sub x/Cu/sub 3/O/sub ...

Neural mechanisms underlying valence inferences to sound: The role of the right angular gyrus.

Science.gov (United States)

Bravo, Fernando; Cross, Ian; Hawkins, Sarah; Gonzalez, Nadia; Docampo, Jorge; Bruno, Claudio; Stamatakis, Emmanuel Andreas

2017-07-28

We frequently infer others' intentions based on non-verbal auditory cues. Although the brain underpinnings of social cognition have been extensively studied, no empirical work has yet examined the impact of musical structure manipulation on the neural processing of emotional valence during mental state inferences. We used a novel sound-based theory-of-mind paradigm in which participants categorized stimuli of different sensory dissonance level in terms of positive/negative valence. Whilst consistent with previous studies which propose facilitated encoding of consonances, our results demonstrated that distinct levels of consonance/dissonance elicited differential influences on the right angular gyrus, an area implicated in mental state attribution and attention reorienting processes. Functional and effective connectivity analyses further showed that consonances modulated a specific inhibitory interaction from associative memory to mental state attribution substrates. Following evidence suggesting that individuals with autism may process social affective cues differently, we assessed the relationship between participants' task performance and self-reported autistic traits in clinically typical adults. Higher scores on the social cognition scales of the AQ were associated with deficits in recognising positive valence in consonant sound cues. These findings are discussed with respect to Bayesian perspectives on autistic perception, which highlight a functional failure to optimize precision in relation to prior beliefs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simulating Ru L3-edge X-ray absorption spectroscopy with time-dependent density functional theory: model complexes and electron localization in mixed-valence metal dimers.

Science.gov (United States)

Van Kuiken, Benjamin E; Valiev, Marat; Daifuku, Stephanie L; Bannan, Caitlin; Strader, Matthew L; Cho, Hana; Huse, Nils; Schoenlein, Robert W; Govind, Niranjan; Khalil, Munira

2013-05-30

Ruthenium L3-edge X-ray absorption (XA) spectroscopy probes unoccupied 4d orbitals of the metal atom and is increasingly being used to investigate the local electronic structure in ground and excited electronic states of Ru complexes. The simultaneous development of computational tools for simulating Ru L3-edge spectra is crucial for interpreting the spectral features at a molecular level. This study demonstrates that time-dependent density functional theory (TDDFT) is a viable and predictive tool for simulating ruthenium L3-edge XA spectroscopy. We systematically investigate the effects of exchange correlation functional and implicit and explicit solvent interactions on a series of Ru(II) and Ru(III) complexes in their ground and electronic excited states. The TDDFT simulations reproduce all of the experimentally observed features in Ru L3-edge XA spectra within the experimental resolution (0.4 eV). Our simulations identify ligand-specific charge transfer features in complicated Ru L3-edge spectra of [Ru(CN)6](4-) and Ru(II) polypyridyl complexes illustrating the advantage of using TDDFT in complex systems. We conclude that the B3LYP functional most accurately predicts the transition energies of charge transfer features in these systems. We use our TDDFT approach to simulate experimental Ru L3-edge XA spectra of transition metal mixed-valence dimers of the form [(NC)5M(II)-CN-Ru(III)(NH3)5](-) (where M = Fe or Ru) dissolved in water. Our study determines the spectral signatures of electron delocalization in Ru L3-edge XA spectra. We find that the inclusion of explicit solvent molecules is necessary for reproducing the spectral features and the experimentally determined valencies in these mixed-valence complexes. This study validates the use of TDDFT for simulating Ru 2p excitations using popular quantum chemistry codes and providing a powerful interpretive tool for equilibrium and ultrafast Ru L3-edge XA spectroscopy.

Systematic study on intermolecular valence-band dispersion in molecular crystalline films

International Nuclear Information System (INIS)

Yamane, Hiroyuki; Kosugi, Nobuhiro

2015-01-01

Highlights: • Intermolecular valence-band dispersion of crystalline films of phthalocyanines. • Intermolecular transfer integral versus lattice constant. • Site-specific intermolecular interaction and resultant valence-band dispersion. • Band narrowing effect induced by elevated temperature. - Abstract: Functionalities of organic semiconductors are governed not only by individual properties of constituent molecules but also by solid-state electronic states near the Fermi level such as frontier molecular orbitals, depending on weak intermolecular interactions in various conformations. The individual molecular property has been widely investigated in detail; on the other hand, the weak intermolecular interaction is difficult to investigate precisely due to the presence of the structural and thermal energy broadenings in organic solids. Here we show quite small but essential intermolecular valence band dispersions and their temperature dependence of sub-0.1-eV scale in crystalline films of metal phthalocyanines (H_2Pc, ZnPc, CoPc, MnPc, and F_1_6ZnPc) by using angle-resolved photoemission spectroscopy (ARPES) with synchrotron radiation. The observed bands show intermolecular and site dependent dispersion widths, phases, and periodicities, for different chemical substitution of terminal groups and central metals in the phthalocyanine molecule. The precise and systematic band-dispersion measurement would be a credible approach toward the comprehensive understanding of intermolecular interactions and resultant charge transport properties as well as their tuning by substituents in organic molecular systems.

Lying about the valence of affective pictures: an fMRI study.

Directory of Open Access Journals (Sweden)

Tatia M C Lee

Full Text Available The neural correlates of lying about affective information were studied using a functional magnetic resonance imaging (fMRI methodology. Specifically, 13 healthy right-handed Chinese men were instructed to lie about the valence, positive or negative, of pictures selected from the International Affective Picture System (IAPS while their brain activity was scanned by a 3T Philip Achieva scanner. The key finding is that the neural activity associated with deception is valence-related. Comparing to telling the truth, deception about the valence of the affectively positive pictures was associated with activity in the inferior frontal, cingulate, inferior parietal, precuneus, and middle temporal regions. Lying about the valence of the affectively negative pictures, on the other hand, was associated with activity in the orbital and medial frontal regions. While a clear valence-related effect on deception was observed, common neural regions were also recruited for the process of deception about the valence of the affective pictures. These regions included the lateral prefrontal and inferior parietal regions. Activity in these regions has been widely reported in fMRI studies on deception using affectively-neutral stimuli. The findings of this study reveal the effect of valence on the neural activity associated with deception. Furthermore, the data also help to illustrate the complexity of the neural mechanisms underlying deception.

The extended variant of the bond valence-bond length correlation curve for boron(III)-oxygen bonds

International Nuclear Information System (INIS)

Sidey, Vasyl

2015-01-01

The extended variant of the bond valence (s)-bond length (r) correlation curve for boron(III)-oxygen bonds has been closely approximated using the three-parameter function s = [k/(r - l)] - m, where s is measured in valence units (vu), r is measured in Aa, k = 0.53 Aa.vu, l = 0.975(1) Aa and m = 0.32 vu. The function s = exp[(r 0 - r)/b] traditionally used in the modern bond valence model requires the separate set of the bond valence parameters (r 0 = 1.362 Aa; b = 0.23 Aa) in order to approximate the above s-r curve for the bonds shorter than ∝1.3 Aa.

The chemical bond in inorganic chemistry the bond valence model

CERN Document Server

Brown, I David

2016-01-01

The bond valence model is a version of the ionic model in which the chemical constraints are expressed in terms of localized chemical bonds formed by the valence charge of the atoms. Theorems derived from the properties of the electrostatic flux predict the rules obeyed by both ionic and covalent bonds. They make quantitative predictions of coordination number, crystal structure, bond lengths and bond angles. Bond stability depends on the matching of the bonding strengths of the atoms, while the conflicting requirements of chemistry and space lead to the structural instabilities responsible for the unusual physical properties displayed by some materials. The model has applications in many fields ranging from mineralogy to molecular biology.

Valence Scaling of Dynamic Facial Expressions Is Altered in High-Functioning Subjects with Autism Spectrum Disorders: An FMRI Study

Science.gov (United States)

Rahko, Jukka S.; Paakki, Jyri-Johan; Starck, Tuomo H.; Nikkinen, Juha; Pauls, David L.; Katsyri, Jari V.; Jansson-Verkasalo, Eira M.; Carter, Alice S.; Hurtig, Tuula M.; Mattila, Marja-Leena; Jussila, Katja K.; Remes, Jukka J.; Kuusikko-Gauffin, Sanna A.; Sams, Mikko E.; Bolte, Sven; Ebeling, Hanna E.; Moilanen, Irma K.; Tervonen, Osmo; Kiviniemi, Vesa

2012-01-01

FMRI was performed with the dynamic facial expressions fear and happiness. This was done to detect differences in valence processing between 25 subjects with autism spectrum disorders (ASDs) and 27 typically developing controls. Valence scaling was abnormal in ASDs. Positive valence induces lower deactivation and abnormally strong activity in ASD…

If You Don't Have Valence, Ask Your Neighbor: Evaluation of Neutral Words as a Function of Affective Semantic Associates.

Science.gov (United States)

Kuhlmann, Michael; Hofmann, Markus J; Jacobs, Arthur M

2017-01-01

How do humans perform difficult forced-choice evaluations, e.g., of words that have been previously rated as being neutral? Here we tested the hypothesis that in this case, the valence of semantic associates is of significant influence. From corpus based co-occurrence statistics as a measure of association strength we computed individual neighborhoods for single neutral words comprised of the 10 words with the largest association strength. We then selected neutral words according to the valence of the associated words included in the neighborhoods, which were either mostly positive, mostly negative, mostly neutral or mixed positive and negative, and tested them using a valence decision task (VDT). The data showed that the valence of semantic neighbors can predict valence judgments to neutral words. However, all but the positive neighborhood items revealed a high tendency to elicit negative responses. For the positive and negative neighborhood categories responses congruent with the neighborhood's valence were faster than incongruent responses. We interpret this effect as a semantic network process that supports the evaluation of neutral words by assessing the valence of the associative semantic neighborhood. In this perspective, valence is considered a semantic super-feature, at least partially represented in associative activation patterns of semantic networks.

Spin Dynamics and Magnetic Ordering in Mixed Valence Systems

DEFF Research Database (Denmark)

Shapiro, S. M.; Bjerrum Møller, Hans; Axe, J. D.

1978-01-01

. 0 meV at the transition to the alpha phase. The temperature independence of the susceptibility within the gamma phase cannot be simply reconciled with the temperature dependence of the valence within the gamma phase. TmSe is shown to order in a type I antiferromagnetic structure below T//N similar 3....... 2 K. The magnetic phase diagram is understood as a successive domain reorientation and a metamagnetic phase transition for T less than 3 K with increasing field. The mixed valence nature manifests itself in a reduced moment and a markedly altered crystal field. Another sample of TmSe with a lattice...

Valency stabilization of Polyvalent Iron Ions in Solution By some Organic additives during Gamma Irradiation

International Nuclear Information System (INIS)

Barakat, M.F.; Abdel Hamid, M.M.

2012-01-01

Valency stabilization of polyvalent ions in gamma irradiated aqueous solutions is sometimes necessary for the success of some chemical operations. In some previous publications valency stabilization of some polyvalent ions in solution upon gamma irradiation was achieved by using additives capable of interacting with the oxidizing or reducing species formed by water radiolysis in the medium. The results showed that the duration of valency stabilization depends on the concentration of the additives used.In the present work, a series of some organic additives has been used to investigate their capability in inducing valency stabilization of polyvalent iron ions when subjected to extended gamma irradiation periods. The results showed that the efficiency of valency stabilization depends on the amount and chemical structure of the organic additive used

Valence band variation in Si (110) nanowire induced by a covered insulator

International Nuclear Information System (INIS)

Hong-Hua, Xu; Xiao-Yan, Liu; Yu-Hui, He; Gang, Du; Ru-Qi, Han; Jin-Feng, Kang; Chun, Fan; Ai-Dong, Sun

2010-01-01

In this work, we investigate strain effects induced by the deposition of gate dielectrics on the valence band structures in Si (110) nanowire via the simulation of strain distribution and the calculation of a generalized 6×6k·p strained valence band. The nanowire is surrounded by the gate dielectric. Our simulation indicates that the strain of the amorphous SiO 2 insulator is negligible without considering temperature factors. On the other hand, the thermal residual strain in a nanowire with amorphous SiO 2 insulator which has negligible lattice misfit strain pushes the valence subbands upwards by chemical vapour deposition and downwards by thermal oxidation treatment. In contrast with the strain of the amorphous SiO 2 insulator, the strain of the HfO 2 gate insulator in Si (110) nanowire pushes the valence subbands upwards remarkably. The thermal residual strain by HfO 2 insulator contributes to the up-shifting tendency. Our simulation results for valence band shifting and warping in Si nanowires can provide useful guidance for further nanowire device design. (classical areas of phenomenology)

Calculation of the structure and IR spectrum of methyl-b-D-glucopyranoside by density functional theory

International Nuclear Information System (INIS)

Babkov, L.M.; Korolevich, M.V.; Moisejkina, E.A.

2010-01-01

Structural-dynamic models of methyl-b-D-glucopyranoside have been constructed by a density functional method using a B3LYP functional in bases 6-31G(d) and 6-31+G(d,p). Energies have been minimized. Structures, dipole moments, polarizabilities, frequencies of normal modes in the harmonic approximation, and the intensity distribution in the molecular IR spectrum have been calculated. The calculation results have been compared with both the experimental spectra of methyl-b-D-glucopyranoside in the region 400-3700 cm -1 and data obtained within the framework of an approach that uses the classical valence-force method to calculate normal mode frequencies and the quantum-chemical CNDO/2 technique to calculate the electronic structure. (authors)

Valence skipping driven superconductivity and charge Kondo effect

International Nuclear Information System (INIS)

Yanagisawa, Takashi; Hase, Izumi

2013-01-01

Highlights: •Valence skipping in metallic compounds can give rise to an unconventional superconductivity. •Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. •The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. •We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. •There is a high temperature region near the boundary. -- Abstract: Valence skipping in metallic compounds can give rise to an unconventional superconductivity. Several elements in the periodic table show valence skipping (or valence missing), for example, Bi forms the compounds in valence states +3 and +5. The doping of valence skipping elements will induce superconductivity and this will lead to a possibility of high temperature superconductivity. We consider the Wolf model with negative-U impurities, and show a phase diagram including superconducting phase. The superconducting state is changed into a metallic state with a local singlet as the attractive interaction |U| increases. There is a high temperature region near the boundary

Simultaneous conditioning of valence and arousal.

Science.gov (United States)

Gawronski, Bertram; Mitchell, Derek G V

2014-01-01

Evaluative conditioning (EC) refers to the change in the valence of a conditioned stimulus (CS) due to its pairing with a positive or negative unconditioned stimulus (US). To the extent that core affect can be characterised by the two dimensions of valence and arousal, EC has important implications for the origin of affective responses. However, the distinction between valence and arousal is rarely considered in research on EC or conditioned responses more generally. Measuring the subjective feelings elicited by a CS, the results from two experiments showed that (1) repeated pairings of a CS with a positive or negative US of either high or low arousal led to corresponding changes in both CS valence and CS arousal, (2) changes in CS arousal, but not changes in CS valence, were significantly related to recollective memory for CS-US pairings, (3) subsequent presentations of the CS without the US reduced the conditioned valence of the CS, with conditioned arousal being less susceptible to extinction and (4) EC effects were stronger for high arousal than low arousal USs. The results indicate that the conditioning of affective responses can occur simultaneously along two independent dimensions, supporting evidence in related areas that calls for a consideration of both valence and arousal. Implications for research on EC and the acquisition of emotional dispositions are discussed.

Valence holes observed in nanodiamonds dispersed in water

Science.gov (United States)

Petit, Tristan; Pflüger, Mika; Tolksdorf, Daniel; Xiao, Jie; Aziz, Emad F.

2015-02-01

Colloidal dispersion is essential for most nanodiamond applications, but its influence on nanodiamond electronic properties remains unknown. Here we have probed the electronic structure of oxidized detonation nanodiamonds dispersed in water by using soft X-ray absorption and emission spectroscopies at the carbon and oxygen K edges. Upon dispersion in water, the π* transitions from sp2-hybridized carbon disappear, and holes in the valence band are observed.Colloidal dispersion is essential for most nanodiamond applications, but its influence on nanodiamond electronic properties remains unknown. Here we have probed the electronic structure of oxidized detonation nanodiamonds dispersed in water by using soft X-ray absorption and emission spectroscopies at the carbon and oxygen K edges. Upon dispersion in water, the π* transitions from sp2-hybridized carbon disappear, and holes in the valence band are observed. Electronic supplementary information (ESI) available: Experimental methods, details on XAS/XES normalization and background correction procedures. See DOI: 10.1039/c4nr06639a

Spin dynamics and magnetic ordering in mixed valence systems

International Nuclear Information System (INIS)

Shapiro, S.M.; Moller, H.B.; Axe, J.D.; Birgeneau, R.J.; Bucher, E.

1977-01-01

Neutron scattering measurements are reported on the mixed valence compounds Ce/sub 1-x/Th/sub x/ and TmSe. The Chi''(Q,ω) as derived from the inelastic spectra of Ce 0 . 74 Th 0 . 26 shows a peak in the γ phase near 20.0 meV and shifts abruptly to greater than 70.0 meV at the transition to the α phase. The temperature independence of the susceptibility within the γ phase cannot be simply reconciled with the temperature dependence of the valence within the γ phase. TmSe is shown to order in a type I antiferromagnetic structure below T/sub N/ approx. 3.2 K. The magnetic phase diagram is understood as a successive domain reorientation and a metamagnetic phase transition for T 3+ orders in a type II structure but never achieves long range order

Simulating Ru L ₃ -Edge X-ray Absorption Spectroscopy with Time-Dependent Density Functional Theory: Model Complexes and Electron Localization in Mixed-Valence Metal Dimers

Energy Technology Data Exchange (ETDEWEB)

Van Kuiken, Benjamin E.; Valiev, Marat; Daifuku, Stephanie L.; Bannan, Caitlin; Strader, Matthew L.; Cho, Hana; Huse, Nils; Schoenlein, Robert W.; Govind, Niranjan; Khalil, Munira

2013-05-30

Ruthenium L3-edge X-ray absorption (XA) spectroscopy probes unoccupied 4d orbitals of the metal atom and is increasingly being used to investigate the local electronic structure in ground and excited electronic states of Ru complexes. The simultaneous development of computational tools for simulating Ru L3-edge spectra is crucial for interpreting the spectral features at a molecular level. This study demonstrates that time-dependent density functional theory (TDDFT) is a viable and predictive tool for simulating ruthenium L3-edge XA spectroscopy. We systematically investigate the effects of exchange correlation functional and implicit and explicit solvent interactions on a series of RuII and RuIII complexes in their ground and electronic excited states. The TDDFT simulations reproduce all of the experimentally observed features in Ru L3-edge XA spectra within the experimental resolution (0.4 eV). Our simulations identify ligand-specific charge transfer features in complicated Ru L3-edge spectra of [Ru(CN)6]4- and RuII polypyridyl complexes illustrating the advantage of using TDDFT in complex systems. We conclude that the B3LYP functional most accurately predicts the transition energies of charge transfer features in these systems. We use our TDDFT approach to simulate experimental Ru L3-edge XA spectra of transition metal mixed-valence dimers of the form [(NC)5MII-CN-RuIII(NH3)5] (where M = Fe or Ru) dissolved in water. Our study determines the spectral signatures of electron delocalization in Ru L3-edge XA spectra. We find that the inclusion of explicit solvent molecules is necessary for reproducing the spectral features and the experimentally determined valencies in these mixed-valence complexes. This study validates the use of TDDFT for simulating Ru 2p excitations using popular quantum chemistry codes and providing a powerful interpretive tool for equilibrium and ultrafast Ru L3-edge XA spectroscopy.

Determination of a natural valence-band offset - The case of HgTe and CdTe

Science.gov (United States)

Shih, C. K.; Spicer, W. E.

1987-01-01

A method to determine a natural valence-band offset (NVBO), i.e., the change in the valence-band maximum energy which is intrinsic to the bulk band structures of semiconductors is proposed. The HgTe-CdTe system is used as an example in which it is found that the valence-band maximum of HgTe lies 0.35 + or - 0.06 eV above that of CdTe. The NVBO of 0.35 eV is in good agreement with the X-ray photoemission spectroscopy measurement of the heterojunction offset. The procedure to determine the NVBO between semiconductors, and its implication on the heterojunction band lineup and the electronic structures of semiconductor alloys, are discussed.

Valence electron structure analysis of refining mecha-nism of Sc and Ti additions on aluminum

Institute of Scientific and Technical Information of China (English)

LI PieJie; YE YiCong; HE LiangJu

2009-01-01

The mechanism of the difference of refining effect between Sc and Ti adding to aluminum can not be explained substantially with traditional theory. Valence electron structures of AI-Ti and Al-Sc alloys have been studied by using the empirical electron theory of solids and molecules (EET). The covalent bond electron numbers and interfacial electron density differences are calculated. The conclusion is that, in the two alloys, different covalent bond electron numbers of nucleation particles, and different electron densities on the interface between the second phase particles and the matrix, fundamentally lead to the difference of refining effect between Sc and Ti adding to aluminum.

Structural and magnetic characterization of mixed valence Co(II, III)xZn1−xO epitaxial thin films

International Nuclear Information System (INIS)

Negi, D.S.; Loukya, B.; Dileep, K.; Sahu, R.; Shetty, S.; Kumar, N.; Ghatak, J.; Pachauri, N.; Gupta, A.; Datta, R.

2014-01-01

In this article, we report on the Co atom incorporation, secondary phase formation and composition-dependent magnetic and optical properties of mixed valence Co(II, III) x Zn 1−x O epitaxial thin films grown by pulsed laser deposition. The intended total Co concentration is varied between ∼6–60 at.% with relatively higher concentration of +3 over +2 charge state. Mixed valence Co(II, III) shows high solubility in ZnO (up to 38 at.%) and ferromagnetism is observed in samples with total Co incorporation of ∼29 and 38 at.%. Electron diffraction pattern and high resolution transmission electron microscopy images reveal single crystalline nature of the thin films with wurtzite structure. Co oxide interlayer, with both rock salt and spinel structure, are observed to be formed between the substrate and wurtzite film for total Co concentration at ∼17 at.% and above. Magnetization shows composition dependence with a saturation moment value of ∼93 emu cm −3 and a coercive field of ∼285 Oe observed for ∼38 at.% Co:ZnO films. Ferromagnetism was not observed for films with Co concentration 17 and 9 at.%. The Co oxide interlayer does not show any ferromagnetism. All the films are n-type with carrier concentration ∼10 19 cm −3 . The observed magnetism is probably resulting from direct antiferromagntic exchange interaction between Co 2+ and Co 3+ ions favored by heavy Co alloying giving rise to ferrimagnetism in the system. - Highlights: • Mixed valence Co doped ZnO ferromagnetic single crystal thin film. • Secondary phase formation in terms of CoO and Co3O4 and magnetism is observed only for high Co alloying. • Cathodoluminescence (CL) data showing increase in band gap with Co concentrations

Vanadium K XANES of synthetic olivine: Valence determinations and crystal orientation effects

International Nuclear Information System (INIS)

Sutton, S.R.; Newville, M.

2005-01-01

Vanadium can exist in a large number of valence states in nature (2+?, 3+, 4+ and 5+) and determinations of V valence is therefore valuable in defining the oxidation states of earth and planetary materials over a large redox range. Synchrotron-based x-ray absorption near edge structure (XANES) spectroscopy is well-suited for measurements of V valence with ∼micrometer spatial resolution and ∼ppm elemental sensitivity. Applications of microXANES have been demonstrated for basaltic glasses. Applications to minerals are feasible but complicated by orientation effects (e.g. due to polarization of the synchrotron x-ray beam) and some results for spinel have been reported. Here we report initial results for olivine from laboratory crystallization ex-periments. The goal is to define the valence partition-ing between olivine and melt and quantify the magnitude of orientation effects, the latter tested by measuring grains at a variety of orientations in the same charge.

Electronic structure and nature of the ground state of the mixed-valence binuclear tetra(mu-1,8-naphthyridine-N,N')-bis(halogenonickel) tetraphenylborate complexes: experimental and DFT characterization.

Science.gov (United States)

Bencini, Alessandro; Berti, Elisabetta; Caneschi, Andrea; Gatteschi, Dante; Giannasi, Elisa; Invernizzi, Ivana

2002-08-16

The ground state electronic structure of the mixed-valence systems [Ni(2)(napy)(4)X(2)](BPh(4)) (napy=1,8-naphthyridine; X=Cl, Br, I) was studied with combined experimental (X-ray diffraction, temperature dependence of the magnetic susceptibility, and high-field EPR spectroscopy) and theoretical (DFT) methods. The zero-field splitting (zfs) ground S=3/2 spin state is axial with /D/ approximately 3 cm(-1). The iodide derivative was found to be isostructural with the previously reported bromide complex, but not isomorphous. The compound crystallizes in the monoclinic system, space group P2(1)/n, with a=17.240(5), b=26.200(5), c=11.340(5) A, beta=101.320(5) degrees. DFT calculations were performed on the S=3/2 state to characterize the ground state potential energy surface as a function of the nuclear displacements. The molecules can thus be classified as Class III mixed-valence compounds with a computed delocalization parameter, B=3716, 3583, and 3261 cm(-1) for the Cl, Br, and I derivatives, respectively.

A theoretical and (e,2e) experimental investigation into the complete valence electronic structure of (1.1.1) propellane

Energy Technology Data Exchange (ETDEWEB)

Adcock, W.; Clark, C.I. [Flinders Univ. of South Australia, Bedford Park, SA (Australia); Brunger, M.J.; McCarthy, I.E. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences; Michalewicz, M.T. [CSIRO, Carlton, VIC (Australia). Division of Information Technology; Von Niessen, W. [Technische Univ., Braunschweig (Germany). Institute fur Physikalische and Theoretische Chemie; Weigold, E. [Australian National Univ., Canberra, ACT (Australia). Inst. of Advanced Studies; Winkler, D.A. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC (Australia). Div. of Chemical Physics

1996-08-01

The first comprehensive electronic structural study of the complete valence shell of [1.1.1] propellane is reported. Binding energy spectra were measured in the energy regime 3.5-46.5 eV over a range of different target electron momentum so that individual orbital momentum profiles could also be determined. These binding energy spectra were collected using an energy dispersive multichannel electron momentum spectrometer at a total energy of 1000 eV, with a coincidence energy resolution of 1.38 eV and a momentum resolution of about 0.1 a.u. The experimental orbital electron momentum profiles are compared with those calculated in the plane wave impulse approximation (PWIA) using both a triple zeta plus polarisation level SCF wavefunction and a further 13 basis sets as calculated using Density Functional Theory (DFT). A critical comparison between the experimental an theoretical momentum distributions (MDs) allows to determine the optimum wavefunction for [1.1.1]propellane. In general, the level of agreement between the experimental and theoretical MDs for the optimum wavefunction for all of the respective valence orbitals was very good. The determination of this wavefunction then allowed to derive the chemically interesting molecular properties of [1.1.1]propellane. These include infrared spectra, bond lengths, bond orders, electron densities and many others. A summary of these results and a comparison of them with the previous results of other workers is presented with the level of agreement typically being good. In particular, the existence of the C1-C3 bridging bond with a bond order of 0.70 was confirmed. 59 refs., 4 tabs., 11 figs.

Valence effects on adsorption: a preliminary assessment of the effects on valence state control on sorption measurements

International Nuclear Information System (INIS)

Meyer, R.E.; Arnold, W.D.; Case, F.; Shiao, S.Y.; Palmer, D.A.

1983-01-01

Electrochemical arguments are advanced to illustrate that what is usually measured in practice is a mixed potential determined by the kinetics of the electrode processes occurring at the indicator electrode. Valence states can be altered electrochemically or by use of added chemical reagents, including redox couples which can hold the potential to relatively specific potentials. The disadvantage of added chemical reagents is that they may alter the characteristics of the sorption reactions by interaction with the sorbent. Electrochemical methods are versatile and do not add reagents, but in some caes the nuclide can adsorb on the electrode itself. A description is given of the application of the electrochemical method of valence control to determination of sorption of Np(V) on alumina. Valence state control and analysis can be used to study possible redox reactions on materials which might be used as backfill materials. A description is given of survey experiments with a number of sulfides and iron-containing materials. Valence state analysis is used on the initial solutions and leachate from acid leaches of the sorbent after the sorption experiment to help determine whether valence state change is occurring. The preliminary results indicate that on the sulfides tested, sorption occurs both with and without valence state change

La0,7Sr0,3MnO3 thin layers on SrTiO3(001) substrate. Structure and Mn valence

International Nuclear Information System (INIS)

Riedl, Thomas

2007-01-01

This thesis presents a highly spatially resolved characterization of crystal structure and Mn valence by pictures drawn in the TEM and electron-energy-loss ionization edges. The Mn valence determined for the internal od the studied LSMO layers agrees with the nomial value of 3.3, while on some LSMO/STO interfaces between substrate and layers as well as between multilayers a reduction by 0.1..0.2 is to be observed. Furthermore the influence of the interface manifests in the occurence of a shoulder on the side of lower energy loss of the Mn L3 edge. The geometrical phase analysis of HRTEM pictures and TEM bright-field pictures prove a tetragonal strain of th LSMO layer crystals, which consist of needle-shaped twin domains. From highly resolved scanning TEM pictures by electrons scattered under large angle results that the LSMO/STO interface exhibit a coherent lattice structure accidentally provided with elementary-cell stages. Especially the stages (single- or multi-stages) mediate the wavy structure of the LSMO/STO interlayers. Finally it is shown that at low thicknes of the TEM lamella the expected crystal-plane inclination exceeds the expected crystal-plane inclination of the twins [de

Cerium valence change in the solid solutions Ce(Rh1-xRux)Sn

International Nuclear Information System (INIS)

Niehaus, Oliver; Riecken, Jan F.; Winter, Florian; Poettgen, Rainer; Muenster Univ.; Abdala, Paula M.; Chevalier, Bernard

2013-01-01

The solid solutions Ce(Rh 1-x Ru x )Sn were investigated by means of susceptibility measurements, specific heat, electrical resistivity, X-ray absorption spectroscopy (XAS), and 119 Sn Moessbauer spectroscopy. Magnetic measurements as well as XAS data show a cerium valence change in dependence on the ruthenium content. Higher ruthenium content causes an increase from 3.22 to 3.45 at 300 K. Furthermore χ and χ -1 data indicate valence fluctuation for cerium as a function of temperature. For example, Ce(Rh 0.8 Ru 0.2 )Sn exhibits valence fluctuations between 3.42 and 3.32 in the temperature range of 10 to 300 K. This could be proven by using the interconfiguration fluctuation (ICF) model introduced by Sales and Wohlleben. Cerium valence change does not influence the tin atoms as proven by 119 Sn Moessbauer spectroscopy, but it influences the electrical properties. Ce(Rh 0.9 Ru 0.1 )Sn behaves like a typical valence fluctuating compound, and higher ruthenium content causes an increase of the metallic behavior. (orig.)

Investigation of structural, electronic and anisotropic elastic properties of Ru-doped WB{sub 2} compound by increased valence electron concentration

Energy Technology Data Exchange (ETDEWEB)

Surucu, Gokhan, E-mail: g_surucu@yahoo.com [Ahi Evran University, Department of Electric and Energy, 40100, Kirsehir (Turkey); Gazi University, Photonics Application and Research Center, 06500, Ankara (Turkey); Kaderoglu, Cagil [Ankara University, Department of Engineering Physics, 06100, Ankara (Turkey); Deligoz, Engin; Ozisik, Haci [Aksaray University, Department of Physics, 68100, Aksaray (Turkey)

2017-03-01

First principles density functional theory (DFT) calculations have been used to investigate the structural, anisotropic elastic and electronic properties of ruthenium doped tungsten-diboride ternary compounds (W{sub 1−x}Ru{sub x}B{sub 2}) for an increasing molar fraction of Ru atom from 0.1 to 0.9 by 0.1. Among the nine different compositions, W{sub 0.3}Ru{sub 0.7}B{sub 2} has been found as the most stable one due to the formation energy and band filling theory calculations. Moreover, the band structures and partial density of states (PDOS) have been computed for each x composition. After obtaining the elastic constants for all x compositions, the secondary results such as Bulk modulus, Young’s modulus, Poisson’s ratio, Shear modulus, and Vickers Hardness of polycrystalline aggregates have been derived and the relevant mechanical properties have been discussed. In addition, the elastic anisotropy has been visualized in detail by plotting the directional dependence of compressibility, Poisson ratio, Young’s and Shear moduli. - Highlights: • Effects of Ru substitution in WB{sub 2} using increased valence electron concentration. • Structural, electronic, mechanic and elastic properties for increasing Ru content. • Considered alloys are incompressible, brittle, stiffer and high hard materials.

Nonorthogonal orbital based N-body reduced density matrices and their applications to valence bond theory. I. Hamiltonian matrix elements between internally contracted excited valence bond wave functions

Science.gov (United States)

Chen, Zhenhua; Chen, Xun; Wu, Wei

2013-04-01

In this series, the n-body reduced density matrix (n-RDM) approach for nonorthogonal orbitals and their applications to ab initio valence bond (VB) methods are presented. As the first paper of this series, Hamiltonian matrix elements between internally contracted VB wave functions are explicitly provided by means of nonorthogonal orbital based RDM approach. To this end, a more generalized Wick's theorem, called enhanced Wick's theorem, is presented both in arithmetical and in graphical forms, by which the deduction of expressions for the matrix elements between internally contracted VB wave functions is dramatically simplified, and the matrix elements are finally expressed in terms of tensor contractions of electronic integrals and n-RDMs of the reference VB self-consistent field wave function. A string-based algorithm is developed for the purpose of evaluating n-RDMs in an efficient way. Using the techniques presented in this paper, one is able to develop new methods and efficient algorithms for nonorthogonal orbital based many-electron theory much easier than by use of the first quantized formulism.

A UniChem and electron momentum spectroscopy investigations into the valence electronic structure of trans 1,3 butadiene

Energy Technology Data Exchange (ETDEWEB)

Michalewicz, M.T. [CSIRO, Supercomputing Support Group, Carlton, VIC (Australia). Division of Information Technology; Winkler, D.A. [Commonwealth Scientific and Industrial Research Organisation (CSIRO), Clayton, VIC (Australia). Div. of Chemical Physics; Brunger, M.J.; McCarthy, L.E. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences; Von Niessen, W. [Flinders Univ. of South Australia, Bedford Park, SA (Australia). School of Physical Sciences

1996-09-01

The experimental (e,2e) coincidence spectroscopy, known as electron momentum spectroscopy (EMS) was applied to the trans 1,3 butadiene (C{sub 4}H{sub 6}) molecule with detailed binding energy spectra and orbital momentum distributions (MDs) being measured. A small selection of this data is presented. The usage of UniChem computational chemistry codes for the Flinders-developed AMOLD program allows to calculate theoretical MDs for each orbital, to help elucidate the valence electronic structure of butadiene. The results of the many-body Green`s function calculation is also presented, to the ADC(3) level, for the binding energies and spectroscopic factors of the respective orbitals of C{sub 4}H{sub 6}. A critical comparison between the experimental and theoretical MDs allows to determine the optimum wavefunction from the basis sets studied. The determination of the wavefunction then allows to make further use of the UniChem package to derive butadiene`s chemically interesting molecular properties. A summary of these results and comparison of them with the previous results of other workers is presented. 23 refs., 2 tabs., 2 figs.

A UniChem and electron momentum spectroscopy investigations into the valence electronic structure of trans 1,3 butadiene

International Nuclear Information System (INIS)

Michalewicz, M.T.; Winkler, D.A.; Brunger, M.J.; McCarthy, L.E.; Von Niessen, W.

1996-09-01

The experimental (e,2e) coincidence spectroscopy, known as electron momentum spectroscopy (EMS) was applied to the trans 1,3 butadiene (C 4 H 6 ) molecule with detailed binding energy spectra and orbital momentum distributions (MDs) being measured. A small selection of this data is presented. The usage of UniChem computational chemistry codes for the Flinders-developed AMOLD program allows to calculate theoretical MDs for each orbital, to help elucidate the valence electronic structure of butadiene. The results of the many-body Green's function calculation is also presented, to the ADC(3) level, for the binding energies and spectroscopic factors of the respective orbitals of C 4 H 6 . A critical comparison between the experimental and theoretical MDs allows to determine the optimum wavefunction from the basis sets studied. The determination of the wavefunction then allows to make further use of the UniChem package to derive butadiene's chemically interesting molecular properties. A summary of these results and comparison of them with the previous results of other workers is presented. 23 refs., 2 tabs., 2 figs

Research Update: Retardation and acceleration of phase separation evaluated from observation of imbalance between structure and valence in LiFePO4/FePO4 electrode

Directory of Open Access Journals (Sweden)

Kazuya Tokuda

2014-07-01

Full Text Available LiFePO4 is a potential positive electrode material for lithium ion batteries. We have experimentally observed an imbalance between the valence change of Fe ions and the structure change from the LiFePO4 phase to the FePO4 phase during delithiation by simultaneous in situ XRD and XANES measurements in an LiFePO4/FePO4 electrode. The ratio of structure change to valence change clearly indicates that the phase separation from LiFePO4 to FePO4 is suppressed at the beginning of delithiation, while it is accelerated at the latter stage, which is due to the coherent strain caused by the lattice misfit between the two phases.

Crossover and valence band Kβ X-rays of chromium oxides

International Nuclear Information System (INIS)

Fazinic, Stjepko; Mandic, Luka; Kavcic, Matjaz; Bozicevic, Iva

2011-01-01

Kβ X-ray spectra of chromium metal and selected chromium oxides were measured twice using medium resolution flat crystal spectrometer and high resolution spectrometer employing Johansson geometry after excitation with 2 MeV proton beams. The positions and intensities of crossover (Kβ'') and valence (Kβ 2,5 ) band X-rays relative to the primary Kβ X-ray components were extracted in a consistent way. The results were compared with the existing data obtained by proton and photon induced ionization mechanisms and theoretical predictions. The obtained results in peak relative positions and intensities were analyzed in order to study dependence on the chromium oxidation states and chromium-oxygen bond lengths in selected chromium oxides. Our results obtained by both spectrometers confirm that the linear trend observed for the valence peak relative energy shift as a function of chromium oxidation number does not depend on the experimental resolution. Experimental results for normalized intensities (i.e. relative intensities divided with the number of chromium-oxygen pairs) of crossover and valence band X-rays obtained by both spectrometers are in very good agreement, and follow exponential relationship with the average Cr-O bond lengths in corresponding chromium oxides. The observed trends in crossover and valence X-rays normalized intensities could be used to measure the average chromium-oxygen bond length in various chromium oxides, with the sum of both crossover and valence X-ray normalized intensities being the most sensitive measure.

Synthesis, Magnetism, and X-ray Molecular Structure of the Mixed-Valence Vanadium(IV/V)-Oxygen Cluster [VO(4) subset(V(18)O(45))](9-).

Science.gov (United States)

Suber, Lorenza; Bonamico, Mario; Fares, Vincenzo

1997-05-07

Within the transition metal oxide systems, vanadium presents a unique chemistry due to its capacity to form a great number of mixed-valence oxo clusters which often have the peculiarity to incorporate species that function, for size, shape, and charge, as templates. Prismatic, lustrous dark brown crystals of [(n-C(4)H(9))NH(3)](9)[V(19)O(49)].7H(2)O are obtained by reacting (n-C(4)H(9)NH(3))VO(3), VOSO(4), and (n-C(4)H(9))NH(2) in H(2)O. The X-ray crystal structure shows an ellipsoidal metal-oxo cluster formed by 15 VO(5) and 3 VO(4) polyhedra surrounding an almost regular VO(4) tetrahedron located on the 3-fold axis of a trigonal cell of dimensions a = 19.113(5) Å and c = 13.743(5) Å with space group P&thremacr; and Z = 2. Exponentially weighted bond valence sum calculations, manganometric titration of the V(IV) centers, and magnetic measurements are consistent with the presence of three localized and three delocalized electrons. Variable-temperature solid-state susceptibility studies indicate antiferromagnetic coupling between V(IV) centers. Cyclic voltammetry in acetonitrile shows a irreversible reduction at -1.24 V and a reversible oxidation at +0.17 V (vs Ag/AgCl). The title compound converts quantitatively to the metal oxide K(2)V(3)O(8) with an extended layered structure as soon as a potassium salt is added to a neutral aqueous solution of the polyoxoanion.

Electronic and transport properties of Cobalt-based valence tautomeric molecules and polymers

Science.gov (United States)

Chen, Yifeng; Calzolari, Arrigo; Buongiorno Nardelli, Marco

2011-03-01

The advancement of molecular spintronics requires further understandings of the fundamental electronic structures and transport properties of prototypical spintronics molecules and polymers. Here we present a density functional based theoretical study of the electronic structures of Cobalt-based valence tautomeric molecules Co III (SQ)(Cat)L Co II (SQ)2 L and their polymers, where SQ refers to the semiquinone ligand, and Cat the catecholate ligand, while L is a redox innocent backbone ligand. The conversion from low-spin Co III ground state to high-spin Co II excited state is realized by imposing an on-site potential U on the Co atom and elongating the Co-N bond. Transport properties are subsequently calculated by extracting electronic Wannier functions from these systems and computing the charge transport in the ballistic regime using a Non-Equilibrium Green's Function (NEGF) approach. Our transport results show distinct charge transport properties between low-spin ground state and high-spin excited state, hence suggesting potential spintronics devices from these molecules and polymers such as spin valves.

Orbital momentum distributions and binding energies for the complete valence shell of molecular iodine

International Nuclear Information System (INIS)

Grisogono, A.M.; Pascual, R.; Weigold, E.

1988-03-01

The complete valence shell binding energy spectrum (8-43eV) of I 2 has been measured by using electron momentum spectroscopy at 1000eV. The complete inner valence region, corresponding to ionization from the 10 σ u and 10 σ g orbitals, has been measured for the first time and shows extensive splitting of the ionization strength due to electron correlation effects in the ion. Many-body calculations using the Green's function method have been carried out and are compared with the data. Momentum distributions, measured in both the outer and inner valence regions, are compared with those given by SCF orbital wave functions calculated with a number of different basis sets. Computed orbital position and momentum density maps for oriented I 2 molecules are discussed in comparison with the measured and calculated spherically averaged momentum distributions

Voice and Valency in San Luis Potosi Huasteco

Science.gov (United States)

Munoz Ledo Yanez, Veronica

2014-01-01

This thesis presents an analysis of the system of transitivity, voice and valency alternations in Huasteco of San Luis Potosi (Mayan) within a functional-typological framework. The study is based on spoken discourse and elicited data collected in the municipalities of Aquismon and Tancanhuitz de Santos in the state of San Luis Potosi, Mexico. The…

Hybrid functional calculation of electronic and phonon structure of BaSnO3

International Nuclear Information System (INIS)

Kim, Bog G.; Jo, J.Y.; Cheong, S.W.

2013-01-01

Barium stannate, BaSnO 3 (BSO), with a cubic perovskite structure, has been highlighted as a promising host material for the next generation transparent oxide electrodes. This study examined theoretically the electronic structure and phonon structure of BSO using hybrid density functional theory based on the HSE06 functional. The electronic structure results of BSO were corrected by extending the phonon calculations based on the hybrid density functional. The fundamental thermal properties were also predicted based on a hybrid functional calculation. Overall, a detailed understanding of the electronic structure, phonon modes and phonon dispersion of BSO will provide a theoretical starting-point for engineering applications of this material. - Graphical Abstract: (a) Crystal structure of BaSnO 3 . The center ball is Ba and small (red) ball on edge is oxygen and SnO 6 octahedrons are plotted as polyhedron. (b) Electronic band structure along the high symmetry point in the Brillouin zone using the HSE06 hybrid functional. (c) The phonon dispersion curve calculated using the HSE06 hybrid functional (d) Zone center lowest energy F 1u phonon mode. Highlights: ► We report the full hybrid functional calculation of not only the electronic structure but also the phonon structure for BaSnO 3 . ► The band gap calculation of HSE06 revealed an indirect gap with 2.48 eV. ► The effective mass at the conduction band minimum and valence band maximum was calculated. ► In addition, the phonon structure of BSO was calculated using the HSE06 functional. ► Finally, the heat capacity was calculated and compared with the recent experimental result.

Mixing positive and negative valence: Affective-semantic integration of bivalent words.

Science.gov (United States)

Kuhlmann, Michael; Hofmann, Markus J; Briesemeister, Benny B; Jacobs, Arthur M

2016-08-05

Single words have affective and aesthetic properties that influence their processing. Here we investigated the processing of a special case of word stimuli that are extremely difficult to evaluate, bivalent noun-noun-compounds (NNCs), i.e. novel words that mix a positive and negative noun, e.g. 'Bombensex' (bomb-sex). In a functional magnetic resonance imaging (fMRI) experiment we compared their processing with easier-to-evaluate non-bivalent NNCs in a valence decision task (VDT). Bivalent NNCs produced longer reaction times and elicited greater activation in the left inferior frontal gyrus (LIFG) than non-bivalent words, especially in contrast to words of negative valence. We attribute this effect to a LIFG-grounded process of semantic integration that requires greater effort for processing converse information, supporting the notion of a valence representation based on associations in semantic networks.

An experimental and theoretical study of the valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine

Science.gov (United States)

Holland, D. M. P.; Powis, I.; Trofimov, A. B.; Menzies, R. C.; Potts, A. W.; Karlsson, L.; Badsyuk, I. L.; Moskovskaya, T. E.; Gromov, E. V.; Schirmer, J.

2017-10-01

The valence shell photoelectron spectra of 2-chloropyridine and 3-chloropyridine have been studied both experimentally and theoretically. Synchrotron radiation has been employed to record angle resolved photoelectron spectra in the photon energy range 20-100 eV, and these have enabled anisotropy parameters and branching ratios to be derived. The experimental results have been compared with theoretical predictions obtained using the continuum multiple scattering Xα approach. This comparison shows that the anisotropy parameter associated with the nominally chlorine lone-pair orbital lying in the molecular plane is strongly affected by the atomic Cooper minimum. In contrast, the photoionization dynamics of the second lone-pair orbital, orientated perpendicular to the molecular plane, seem relatively unaffected by this atomic phenomenon. The outer valence ionization has been studied theoretically using the third-order algebraic-diagrammatic construction (ADC(3)) approximation scheme for the one-particle Green's function, the outer valence Green's function method, and the equation-of-motion (EOM) coupled cluster (CC) theory at the level of the EOM-IP-CCSD and EOM-EE-CC3 models. The convergence of the results to the complete basis set limit has been investigated. The ADC(3) method has been employed to compute the complete valence shell ionization spectra of 2-chloropyridine and 3-chloropyridine. The relaxation mechanism for ionization of the nitrogen σ-type lone-pair orbital (σN LP) has been found to be different to that for the corresponding chlorine lone-pair (σCl LP). For the σN LP orbital, π-π* excitations play the main role in the screening of the lone-pair hole. In contrast, excitations localized at the chlorine site involving the chlorine πCl LP lone-pair and the Cl 4p Rydberg orbital are the most important for the σCl LP orbital. The calculated photoelectron spectra have allowed assignments to be proposed for most of the structure observed in the

Empirical valence bond models for reactive potential energy surfaces: a parallel multilevel genetic program approach.

Science.gov (United States)

Bellucci, Michael A; Coker, David F

2011-07-28

We describe a new method for constructing empirical valence bond potential energy surfaces using a parallel multilevel genetic program (PMLGP). Genetic programs can be used to perform an efficient search through function space and parameter space to find the best functions and sets of parameters that fit energies obtained by ab initio electronic structure calculations. Building on the traditional genetic program approach, the PMLGP utilizes a hierarchy of genetic programming on two different levels. The lower level genetic programs are used to optimize coevolving populations in parallel while the higher level genetic program (HLGP) is used to optimize the genetic operator probabilities of the lower level genetic programs. The HLGP allows the algorithm to dynamically learn the mutation or combination of mutations that most effectively increase the fitness of the populations, causing a significant increase in the algorithm's accuracy and efficiency. The algorithm's accuracy and efficiency is tested against a standard parallel genetic program with a variety of one-dimensional test cases. Subsequently, the PMLGP is utilized to obtain an accurate empirical valence bond model for proton transfer in 3-hydroxy-gamma-pyrone in gas phase and protic solvent. © 2011 American Institute of Physics

Time-resolved imaging of purely valence-electron dynamics during a chemical reaction

DEFF Research Database (Denmark)

Hockett, Paul; Bisgaard, Christer Z.; Clarkin, Owen J.

2011-01-01

Chemical reactions are manifestations of the dynamics of molecular valence electrons and their couplings to atomic motions. Emerging methods in attosecond science can probe purely electronic dynamics in atomic and molecular systems(1-6). By contrast, time-resolved structural-dynamics methods...... such as electron(7-10) or X-ray diffraction(11) and X-ray absorption(12) yield complementary information about the atomic motions. Time-resolved methods that are directly sensitive to both valence-electron dynamics and atomic motions include photoelectron spectroscopy(13-15) and high-harmonic generation(16......,17): in both cases, this sensitivity derives from the ionization-matrix element(18,19). Here we demonstrate a time-resolved molecular-frame photoelectron-angular-distribution (TRMFPAD) method for imaging the purely valence-electron dynamics during a chemical reaction. Specifically, the TRMFPADs measured during...

A study of the valence shell spectroscopic and thermodynamic properties of trifluoronitrosomethane cations

International Nuclear Information System (INIS)

Graham, D.M.; Powis, I.; Underwood, J.G.; Shaw, D.A.; Holland, D.M.P.

2012-01-01

Highlights: ► Fragmentation processes in CF 3 NO have been studied using mass spectrometry. ► Singly charged atomic fragments have been observed. ► Experimental appearance energies have been compared to thermochemical estimates. ► Hartree Fock transition energies and oscillator strengths have been calculated. - Abstract: A time-of-flight mass spectrometry study has been carried out to investigate the fragmentation processes occurring in trifluoronitrosomethane (CF 3 NO) as a result of valence shell photoionisation. Synchrotron radiation has been used to record spectra in the photon energy range ∼10–42 eV, and appearance energies have been determined for 10 fragment ions. At high excitation energies, singly charged atomic fragments have been observed. For the main dissociation channels, leading to the formation of NO + , CF 2 + or CF 3 + , the experimental appearance energies have been compared with thermochemical estimates, and a satisfactory agreement has been found. Structure observed in the total ion yield curve has been interpreted with the aid of excited state transition energies and oscillator strengths obtained in a time-dependent Hartree Fock calculation. The theoretical results show that configuration interaction strongly affects many of the valence states. A HeI excited photoelectron spectrum of CF 3 NO has been measured and the orbital ionisation energies have been compared with theoretical values computed using the Outer Valence Green’s Function approach. A large Franck–Condon gap is observed between the 12a′ (n - ) and the 11a ′ state bands, in accord with the calculated vertical ionisation energies of 10.87 and 16.32 eV for the 12a′ (n − ) and the 11a′ (n + ) orbitals, respectively. In the ion yield curve, the corresponding energy range is strongly influenced by autoionising valence states.

Bond charge approximation for valence electron density in elemental semiconductors

International Nuclear Information System (INIS)

Bashenov, V.K.; Gorbachov, V.E.; Marvakov, D.I.

1985-07-01

The spatial valence electron distribution in silicon and diamond is calculated in adiabatic bond charge approximation at zero temperature when bond charges have the Gaussian shape and their tensor character is taken into account. An agreement between theory and experiment has been achieved. For this purpose Xia's ionic pseudopotentials and Schulze-Unger's dielectric function are used. By two additional parameters Asub(B) and Zsub(B)sup(') we describe the spatial extent of the bond charge and local-field corrections, respectively. The parameter Zsub(B)sup(') accounts for the ratio between the Coulomb and exchange correlation interactions of the valence electrons and its silicon and diamond values have different signs. (author)

Deduction of the chemical state and the electronic structure of Nd{sub 2}Fe{sub 14}B compound from X-ray photoelectron spectroscopy core-level and valence-band spectra

Energy Technology Data Exchange (ETDEWEB)

Wang, Jing; Liang, Le [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Zhang, Lanting, E-mail: lantingzh@sjtu.edu.cn, E-mail: lmsun@sjtu.edu.cn [School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Hirano Institute for Materials Innovation, Shanghai Jiao Tong University, Shanghai 200240 (China); Sun, Limin, E-mail: lantingzh@sjtu.edu.cn, E-mail: lmsun@sjtu.edu.cn [Instrumental Analysis Center, Shanghai Jiao Tong University, Shanghai 200240 (China); Hirano, Shinichi [Hirano Institute for Materials Innovation, Shanghai Jiao Tong University, Shanghai 200240 (China)

2014-10-28

Characterization of chemical state and electronic structure of the technologically important Nd{sub 2}Fe{sub 14}B compound is attractive for understanding the physical nature of its excellent magnetic properties. X-ray photoelectron spectroscopy (XPS) study of such rare-earth compound is important and also challenging due to the easy oxidation of surface and small photoelectron cross-sections of rare-earth 4f electrons and B 2p electrons, etc. Here, we reported an investigation based on XPS spectra of Nd{sub 2}Fe{sub 14}B compound as a function of Ar ion sputtering time. The chemical state of Fe and that of B in Nd{sub 2}Fe{sub 14}B compound can be clearly determined to be 0 and −3, respectively. The Nd in Nd{sub 2}Fe{sub 14}B compound is found to have the chemical state of close to +3 instead of +3 as compared with the Nd in Nd{sub 2}O{sub 3}. In addition, by comparing the valence-band spectrum of Nd{sub 2}Fe{sub 14}B compound to that of the pure Fe, the contributions from Nd, Fe, and B to the valence-band structure of Nd{sub 2}Fe{sub 14}B compound is made more clear. The B 2p states and B 2s states are identified to be at ∼11.2 eV and ∼24.6 eV, respectively, which is reported for the first time. The contribution from Nd 4f states can be identified both in XPS core-level spectrum and XPS valence-band spectrum. Although Nd 4f states partially hybridize with Fe 3d states, Nd 4f states are mainly localized in Nd{sub 2}Fe{sub 14}B compound.

Beyond Valence and Magnitude: a Flexible Evaluative Coding System in the Brain

Science.gov (United States)

Gu, Ruolei; Lei, Zhihui; Broster, Lucas; Wu, Tingting; Jiang, Yang; Luo, Yue-jia

2013-01-01

Outcome evaluation is a cognitive process that plays an important role in our daily lives. In most paradigms utilized in the field of experimental psychology, outcome valence and outcome magnitude are the two major features investigated. The classical “independent coding model” suggest that outcome valence and outcome magnitude are evaluated by separate neural mechanisms that may be mapped onto discrete event-related potential (ERP) components: feedback-related negativity (FRN) and the P3, respectively. To examine this model, we presented outcome valence and magnitude sequentially rather than simultaneously. The results reveal that when only outcome valence or magnitude is known, both the FRN and the P3 encode that outcome feature; when both aspects of outcome are known, the cognitive functions of the two components dissociate: the FRN responds to the information available in the current context, while the P3 pattern depends on outcome presentation sequence. The current study indicates that the human evaluative system, indexed in part by the FRN and the P3, is more flexible than previous theories suggested. PMID:22019775

Block correlated second order perturbation theory with a generalized valence bond reference function

International Nuclear Information System (INIS)

Xu, Enhua; Li, Shuhua

2013-01-01

The block correlated second-order perturbation theory with a generalized valence bond (GVB) reference (GVB-BCPT2) is proposed. In this approach, each geminal in the GVB reference is considered as a “multi-orbital” block (a subset of spin orbitals), and each occupied or virtual spin orbital is also taken as a single block. The zeroth-order Hamiltonian is set to be the summation of the individual Hamiltonians of all blocks (with explicit two-electron operators within each geminal) so that the GVB reference function and all excited configuration functions are its eigenfunctions. The GVB-BCPT2 energy can be directly obtained without iteration, just like the second order Møller–Plesset perturbation method (MP2), both of which are size consistent. We have applied this GVB-BCPT2 method to investigate the equilibrium distances and spectroscopic constants of 7 diatomic molecules, conformational energy differences of 8 small molecules, and bond-breaking potential energy profiles in 3 systems. GVB-BCPT2 is demonstrated to have noticeably better performance than MP2 for systems with significant multi-reference character, and provide reasonably accurate results for some systems with large active spaces, which are beyond the capability of all CASSCF-based methods

Block correlated second order perturbation theory with a generalized valence bond reference function.

Science.gov (United States)

Xu, Enhua; Li, Shuhua

2013-11-07

The block correlated second-order perturbation theory with a generalized valence bond (GVB) reference (GVB-BCPT2) is proposed. In this approach, each geminal in the GVB reference is considered as a "multi-orbital" block (a subset of spin orbitals), and each occupied or virtual spin orbital is also taken as a single block. The zeroth-order Hamiltonian is set to be the summation of the individual Hamiltonians of all blocks (with explicit two-electron operators within each geminal) so that the GVB reference function and all excited configuration functions are its eigenfunctions. The GVB-BCPT2 energy can be directly obtained without iteration, just like the second order Mo̸ller-Plesset perturbation method (MP2), both of which are size consistent. We have applied this GVB-BCPT2 method to investigate the equilibrium distances and spectroscopic constants of 7 diatomic molecules, conformational energy differences of 8 small molecules, and bond-breaking potential energy profiles in 3 systems. GVB-BCPT2 is demonstrated to have noticeably better performance than MP2 for systems with significant multi-reference character, and provide reasonably accurate results for some systems with large active spaces, which are beyond the capability of all CASSCF-based methods.

Double logarithmic term Ln2(1/x) in the polarized non singlet structure function at small x in valon model

International Nuclear Information System (INIS)

Taghavi Shahri Fatemeh; Arash, F.

2009-01-01

We study the low x behavior of non-singlet spin structure Function, of the nucleon in the so-called the valon representation. We find the double logarithmic term Ln 2 (1/x) in the polarized non singlet structure function at small x with using the valon model .The Structure of the valon itself develops through the perturbative dressing of a valence quark in QCD, which is independent of the hosting hadron. The results of non-singlet spin structure Function is in excellent agreement with the experimental data from HERMES collaborations for the entire measured range of x. It also provides an acceptable agreement with the older data from SMC, E143 and E155 experiments. We have further compared our results with those from AA, BB, GRSV, and DNS global fits. (authors)

[Emotional valence of words in schizophrenia].

Science.gov (United States)

Jalenques, I; Enjolras, J; Izaute, M

2013-06-01

Emotion recognition is a domain in which deficits have been reported in schizophrenia. A number of emotion classification studies have indicated that emotion processing deficits in schizophrenia are more pronounced for negative affects. Given the difficulty of developing material suitable for the study of these emotional deficits, it would be interesting to examine whether patients suffering from schizophrenia are responsive to positively and negatively charged emotion-related words that could be used within the context of remediation strategies. The emotional perception of words was examined in a clinical experiment involving schizophrenia patients. This emotional perception was expressed by the patients in terms of the valence associated with the words. In the present study, we investigated whether schizophrenia patients would assign the same negative and positive valences to words as healthy individuals. Twenty volunteer, clinically stable, outpatients from the Psychiatric Service of the University Hospital of Clermont-Ferrand were recruited. Diagnoses were based on DSM-IV criteria. Global psychiatric symptoms were assessed using the Positive and Negative Symptoms Scale (PANSS). The patients had to evaluate the emotional valence of a set of 300 words on a 5-point scale ranging from "very unpleasant" to "very pleasant". . The collected results were compared with those obtained by Bonin et al. (2003) [13] from 97 University students. Correlational analyses of the two studies revealed that the emotional valences were highly correlated, i.e. the schizophrenia patients estimated very similar emotional valences. More precisely, it was possible to examine three separate sets of 100 words each (positive words, neutral words and negative words). The positive words that were evaluated were the more positive words from the norms collected by Bonin et al. (2003) [13], and the negative words were the more negative examples taken from these norms. The neutral words

Electronic properties and bonding in Zr Hx thin films investigated by valence-band x-ray photoelectron spectroscopy

Science.gov (United States)

Magnuson, Martin; Schmidt, Susann; Hultman, Lars; Högberg, Hans

2017-11-01

The electronic structure and chemical bonding in reactively magnetron sputtered Zr Hx (x =0.15 , 0.30, 1.16) thin films with oxygen content as low as 0.2 at.% are investigated by 4d valence band, shallow 4p core-level, and 3d core-level x-ray photoelectron spectroscopy. With increasing hydrogen content, we observe significant reduction of the 4d valence states close to the Fermi level as a result of redistribution of intensity toward the H 1s-Zr 4d hybridization region at ˜6 eV below the Fermi level. For low hydrogen content (x =0.15 , 0.30), the films consist of a superposition of hexagonal closest-packed metal (α phase) and understoichiometric δ -Zr Hx (Ca F2 -type structure) phases, while for x =1.16 , the films form single-phase Zr Hx that largely resembles that of stoichiometric δ -Zr H2 phase. We show that the cubic δ -Zr Hx phase is metastable as thin film up to x =1.16 , while for higher H contents the structure is predicted to be tetragonally distorted. For the investigated Zr H1.16 film, we find chemical shifts of 0.68 and 0.51 eV toward higher binding energies for the Zr 4 p3 /2 and 3 d5 /2 peak positions, respectively. Compared to the Zr metal binding energies of 27.26 and 178.87 eV, this signifies a charge transfer from Zr to H atoms. The change in the electronic structure, spectral line shapes, and chemical shifts as a function of hydrogen content is discussed in relation to the charge transfer from Zr to H that affects the conductivity by charge redistribution in the valence band.

Reply to Isgur's comments on valence QCD

International Nuclear Information System (INIS)

Liu, K.F.

2000-01-01

With the goal of understanding the complexity of QCD and the role of symmetry in dynamics, the authors studied a field theory called Valence QCD (VQCD) in which the Z graphs are forbidden so that the Fock space is limited to the valence quarks. The authors calculated nucleon form factors, matrix elements, and hadron masses both with this theory and with quenched QCD on a set of lattices with the same gauge background. Comparing the results of the lattice calculations in these two theories, the authors drew conclusions regarding the SU(6) valence quark model and chiral symmetry. While recognizing the goal of VQCD, Nathan Isgur disagrees on some of the conclusions the authors have drawn. The foremost objection raised in section 2 is to their suggestion that the major part of the hyperfine splittings in baryons is due to Goldstone boson exchange and not one-gluon-exchange (OGE) interactions. The logic of Isgur's objection is that VQCD yields a spectroscopy vastly different from quenched QCD and therefore the structure of the hadrons (to which hyperfine splittings in a quark model are intimately tied) is also suspect so no definite conclusions are possible. To put this into perspective it should be emphasized at the outset that spectroscopy is only one aspect of hadron physics examined in section 1. The authors have studied the axial and scalar couplings of nucleon in terms of F A /D A and F S /D S , the neutron to proton magnetic moment ratio μn/μp, and various form factors. None of these results reveal any pathologies of hadron structure and turn out to be close to the SU(6) relations, as expected. In fact this is what motivated the study of valence degrees of freedom via VQCD. In section 2 the authors address specific issues related to spectroscopy in VQCD. Isgur also presented more general arguments against the idea of boson exchange as a contributor to hyperfine effects. A cornerstone of his discussion is the unifying aspect of OGE in a quark model picture. The

Effective valence as the control parameter of the superconducting ...

African Journals Online (AJOL)

One approach to investigating the superconductivity in the ironbased materials is understanding the chemical and structural parameters that can be used to tune their remarkably high Tc. In this paper, we have demonstrated that the effective valence of iron can be used as the control parameter to tune the Tc of this family of ...

Orbital momentum distribution and binding energies for the complete valence shell of molecular chlorine by electron momentum spectroscopy

International Nuclear Information System (INIS)

Frost, L.; Grisogono, A.M.; McCarthy, I.E.

1986-10-01

The complete valence shell binding energy spectrum (10-50 eV) of Cl 2 has been determined using electron momentum (binary (e,2e)) spectroscopy. The inner valence region, corresponding to 4σ u and 4σ g ionization, has been measured for the first time and shows extensive splitting of the ionization strength due to electron correlation effects. These measurements are compared with the results of many-body calculations using Green's function and CI methods employing unpolarised as well as polarised wave functions. Momentum distributions, measured in both the outer and inner valence regions, are compared with calculations using a range of unpolarised and polarised wave functions. Computed orbital density maps in momentum and position space for oriented Cl 2 molecules are discussed in comparison with the measured and calculated spherically averaged momentum distributions

Valence control of cobalt oxide thin films by annealing atmosphere

International Nuclear Information System (INIS)

Wang Shijing; Zhang Boping; Zhao Cuihua; Li Songjie; Zhang Meixia; Yan Liping

2011-01-01

The cobalt oxide (CoO and Co 3 O 4 ) thin films were successfully prepared using a spin-coating technique by a chemical solution method with CH 3 OCH 2 CH 2 OH and Co(NO 3 ) 2 .6H 2 O as starting materials. The grayish cobalt oxide films had uniform crystalline grains with less than 50 nm in diameter. The phase structure is able to tailor by controlling the annealing atmosphere and temperature, in which Co 3 O 4 thin film was obtained by annealing in air at 300-600, and N 2 at 300, and transferred to CoO thin film by raising annealing temperature in N 2 . The fitted X-ray photoelectron spectroscopy (XPS) spectra of the Co2p electrons are distinguishable from different valence states of cobalt oxide especially for their satellite structure. The valence control of cobalt oxide thin films by annealing atmosphere contributes to the tailored optical absorption property.

Orbital momentum profiles and binding energy spectra for the complete valence shell of molecular fluorine

Energy Technology Data Exchange (ETDEWEB)

Zheng, Y.; Brion, C.E. [British Columbia Univ., Vancouver, BC (Canada). Dept. of Chemistry; Brunger, M.J.; Zhao, K.; Grisogono, A.M.; Braidwood, S.; Weigold, E. [Flinders Univ. of South Australia, Adelaide, SA (Australia). Electronic Structure of Materials Centre; Chakravorty, S.J.; Davidson, E.R. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry; Sgamellotti, A. [Univ di Perugia (Italy). Dipartimento di Chimica; von Niessen, W. [Technische Univ. Braunschweig (Germany). Inst fuer Physikalische

1996-01-01

The first electronic structural study of the complete valence shell binding energy spectrum of molecular fluorine, encompassing both the outer and inner valence regions, is reported. These binding energy spectra as well as the individual orbital momentum profiles have been measured using an energy dispersive multichannel electron momentum spectrometer at a total energy of 1500 eV, with an energy resolution of 1.5 eV and a momentum resolution of 0.1 a.u. The measured binding energy spectra in the energy range of 14-60 eV are compared with the results of ADC(4) many-body Green`s function and also direct-Configuration Interaction (CI) and MRSD-CI calculations. The experimental orbital electron momentum profiles are compared with SCF theoretical profiles calculated using the target Hartree-Fock approximation with a range of basis sets and with Density Functional Theory predictions in the target Kohn-Sham approximation with non-local potentials. The truncated (aug-cc-pv5z) Dunning basis sets were used for the Density Functional Theory calculations which also include some treatment of correlation via the exchange and correlation potentials. Comparisons are also made with the full ion-neutral overlap amplitude calculated with MRSD-CI wave functions. Large, saturated basis sets (199-GTO) were employed for both the high level SCF near Hartree-Fock limit and MRSD-CI calculations to investigate the effects of electron correlation and relaxation. 66 refs., 9 tabs., 9 figs.

Orbital momentum profiles and binding energy spectra for the complete valence shell of molecular fluorine

International Nuclear Information System (INIS)

Zheng, Y.; Brion, C.E.; Brunger, M.J.; Zhao, K.; Grisogono, A.M.; Braidwood, S.; Weigold, E.; Chakravorty, S.J.; Davidson, E.R.; Sgamellotti, A.; von Niessen, W.

1996-01-01

The first electronic structural study of the complete valence shell binding energy spectrum of molecular fluorine, encompassing both the outer and inner valence regions, is reported. These binding energy spectra as well as the individual orbital momentum profiles have been measured using an energy dispersive multichannel electron momentum spectrometer at a total energy of 1500 eV, with an energy resolution of 1.5 eV and a momentum resolution of 0.1 a.u. The measured binding energy spectra in the energy range of 14-60 eV are compared with the results of ADC(4) many-body Green's function and also direct-Configuration Interaction (CI) and MRSD-CI calculations. The experimental orbital electron momentum profiles are compared with SCF theoretical profiles calculated using the target Hartree-Fock approximation with a range of basis sets and with Density Functional Theory predictions in the target Kohn-Sham approximation with non-local potentials. The truncated (aug-cc-pv5z) Dunning basis sets were used for the Density Functional Theory calculations which also include some treatment of correlation via the exchange and correlation potentials. Comparisons are also made with the full ion-neutral overlap amplitude calculated with MRSD-CI wave functions. Large, saturated basis sets (199-GTO) were employed for both the high level SCF near Hartree-Fock limit and MRSD-CI calculations to investigate the effects of electron correlation and relaxation. 66 refs., 9 tabs., 9 figs

X-ray photoelectron spectra structure of actinide compounds stipulated by electrons of the inner valence molecular orbitals (IVMO)

International Nuclear Information System (INIS)

Teterin, Yu. A.; Ivanov, K. E.

1997-01-01

Development of precise X-ray photoelectron spectroscopy using X-ray radiation hν< 1.5 KeV allowed to carry out immediate investigations of fine spectra structure of both weakly bond and deep electrons. Based on the experiments and the obtained results it may be concluded: 1. Under favourable conditions the inner valence molecular orbitals (IVMO) may form in all actinide compounds. 2. The XPS spectra fine structure stipulated by IVMO electrons allows to judge upon the degree of participation of the filled AO electrons in the chemical bond, on the structure o considered atom close environment and the bond lengths in compounds. For amorphous compounds the obtaining of such data based on X-ray structure analysis is restricted. 3. The summary contribution of IVMO electrons to the absolute value of the chemical bonding is comparable with the corresponding value of OMO electrons contribution to the atomic bonding. This fact is very important and new in chemistry. (author)

Resonating-valence-bond superconductors with fermionic projected entangled pair states

NARCIS (Netherlands)

Poilblanc, D.; Corboz, P.; Schuch, N.; Cirac, J.I.

2014-01-01

We construct a family of simple fermionic projected entangled pair states (fPEPS) on the square lattice with bond dimension D=3 which are exactly hole-doped resonating valence bond (RVB) wave functions with short-range singlet bonds. Under doping the insulating RVB spin liquid evolves immediately

Electronic structure of Ag8GeS6

Directory of Open Access Journals (Sweden)

D.I. Bletskan

2017-04-01

Full Text Available For the first time, the energy band structure, total and partial densities of states of Ag8GeS6 crystal were calculated using the ab initio density functional method in LDA and LDA+U approximations. Argyrodite is direct-gap semiconductor with the calculated band gap width Egd = 1.46 eV in the LDA+U approximation. The valence band of argyrodite contains four energy separated groups of occupied subzones. The unique feature of electron-energy structure of Ag8GeS6 crystal is the energy overlapping between the occupied d-states of Ag atoms and the delocalized valence p-states of S atoms in relatively close proximity to the valence band top.

A functionalized surface modification with vanadium nanoparticles of various valences against implant-associated bloodstream infection

Directory of Open Access Journals (Sweden)

Wang J

2017-04-01

ions were released from these nano-VOx films in a sustained manner, and low-valence films possessed better biocompatibility with human fibroblasts. This work may provide new insights for biomedical applications of inorganic vanadium compounds and attract growing attention in this field. From the perspective of surface modification and functionalization, this study holds promise to avail the prophylaxis of bloodstream infections involving implantable biomedical devices. Keywords: surface modification, red blood cell, antibacterial activities, vanadium, nano­materials

Positive valence music restores executive control over sustained attention.

Science.gov (United States)

Baldwin, Carryl L; Lewis, Bridget A

2017-01-01

Music sometimes improves performance in sustained attention tasks. But the type of music employed in previous investigations has varied considerably, which can account for equivocal results. Progress has been hampered by lack of a systematic database of music varying in key characteristics like tempo and valence. The aims of this study were to establish a database of popular music varying along the dimensions of tempo and valence and to examine the impact of music varying along these dimensions on restoring attentional resources following performance of a sustained attention to response task (SART) vigil. Sixty-nine participants rated popular musical selections that varied in valence and tempo to establish a database of four musical types: fast tempo positive valence, fast tempo negative valence, slow tempo positive valence, and slow tempo negative valence. A second group of 89 participants performed two blocks of the SART task interspersed with either no break or a rest break consisting of 1 of the 4 types of music or silence. Presenting positive valence music (particularly of slow tempo) during an intermission between two successive blocks of the SART significantly decreased miss rates relative to negative valence music or silence. Results support an attentional restoration theory of the impact of music on sustained attention, rather than arousal theory and demonstrate a means of restoring sustained attention. Further, the results establish the validity of a music database that will facilitate further investigations of the impact of music on performance.

Moessbauer spectroscopic study on valence-detrapping and trapping of mixed-valence trinuclear iron (III, III, II) fluorine-substitute benzoate complexes

International Nuclear Information System (INIS)

Sakai, Y.; Onaka, S.; Ogiso, R.; Takayama, T.; Takahashi, M.; Nakamoto, T.

2012-01-01

Four mixed-valence trinuclear iron(III, III, II) fluorine-substituted benzoate complexes were synthesized; Fe 3 O(C 6 F 5 COO) 6 (C 5 H 5 N) 3 ·CH 2 Cl 2 (1), Fe 3 O(C 6 F 5 COO) 6 (C 5 H 5 N) 3 (2), Fe 3 O(2H-C 6 F 4 COO) 6 (C 5 H 5 N) 3 (3), and Fe 3 O(4H-C 6 F 4 COO) 6 (C 5 H 5 N) 3 (4). By means of 57 Fe-Moessbauer spectroscopy, valence-detrapping and trapping phenomena have been investigated for the four mixed-valence complexes. The valence state of three iron ions is trapped at lower temperatures while it is fully detrapped at higher temperatures for 1. Valence detrapping is not observed for 2, 3, and 4 even at room temperature, although Moessbauer spectra for 3 and 4 show a complicated temperature dependence. (author)

Valence electronic structure of the indene molecule: Experiment vs. GW calculations

Energy Technology Data Exchange (ETDEWEB)

Umari, P.; Stenuit, G. [CNR-IOM DEMOCRITOS Theory Elettra Group, Basovizza, Trieste (Italy); Castellarin-Cudia, C.; Feyer, V.; Di Santo, G.; Goldoni, A. [Sincrotrone Trieste S.C.p.A., Basovizza, Trieste (Italy); Borghetti, P.; Sangaletti, L. [Dipartimento di Matematica e Fisica, Universita Cattolica del Sacro Cuore, Brescia (Italy)

2011-04-15

We investigate the valence electronic properties in the gas phase of the indene molecule, which is one of the simplest polycyclic aromatic hydrocarbons, with photoemission spectroscopy using synchrotron light and through first-principles calculations using a many-body perturbation theory GW approach. We found an excellent agreement between theory and experiment. This allows us to assign to the peaks appearing in the photoemission spectrum the calculated molecular orbitals. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

A crystal chemical approach to superconductivity. I. A bond-valence sum analysis of inorganic compounds

International Nuclear Information System (INIS)

Liebau, Friedrich; Klein, Hans-Joachim; Wang, Xiqu

2011-01-01

A crystal-chemical approach to superconductivity is described that is intended to complement the corresponding physical approach. The former approach takes into account the distinction between the stoichiometric valence ( stoich V) and the structural valence ( struct V) which is represented by the bond-valence sums (BVS). Through calculations of BVS values from crystal-structure data determined at ambient temperature and pressure it has been found that in chalcogenides und pnictides of the transition metals Fe, Co, Ni, Mn, Hf, and Zr the atoms of the potential superconducting units yield values of vertical stroke BVS vertical stroke = vertical stroke struct V vertical stroke ≥ 1.11 x vertical stroke stoich V vertical stroke, whereas the atoms of the charge reservoirs have in general values of vertical stroke struct V vertical stroke stoich V vertical stroke. In corresponding compounds which contain the same elements but are not becoming superconducting, nearly all atoms are found to have vertical stroke struct V vertical stroke stoich V vertical stroke. For atoms of oxocuprates that are not becoming superconducting and for atoms of the charge reservoirs of oxocuprates that become superconducting, the relation vertical stroke struct V vertical stroke stoich V vertical stroke seems also to be fulfilled, with the exception of Ba. However, in several oxocuprates the relation vertical stroke struct V vertical stroke = 1.11 x vertical stroke stoich V vertical stroke for the atoms that become superconducting units is violated. These violations seem to indicate that in oxocuprates it is the local bond-valence distribution rather than the bond-valence sums that is essential for superconductivity. The present analysis can possibly be used to predict, by a simple consideration of ambient-T, P structures, whether a compound can become an unconventional superconductor at low T, under high P and/or by doping, or not. (orig.)

Valence electron structure and properties of stabilized ZrO2

Institute of Scientific and Technical Information of China (English)

LI JinPing; HAN JieOai; MENG SongHe; ZHANG XingHong

2008-01-01

To reveal the properties of stabilizers in ZrO2 on nanoscopic levels,the valence elec-tron structures of four stable ZrO2 phases and c-ZrO2 were analyzed on the basis of the empirical electron theory of solids and molecules.The results showed that the hybridization levels of Zr atoms in c-ZrO2 doped with Ca and Mg dropped from B17 to B13,the hybridization levels of Zr atoms in c-ZrO2 doped with Y and Ce dropped from B17 to B15,and that the four stabilizing atoms all made the hybridization levels of O atoms drop from level 4 to level 2.The numbers of covalent electrons in the strongest covalent bond in the descending order are c-ZrO2>ZrCeO2>ZrYOZrMgO>ZrCaO.The bond energies of the strongest covalent bond and the melting points of the solid solutions in the descending order are ZrCeO2>c-ZrO2>ZrYO>ZrMgO>ZrCaO.The percent-ages of the total number of covalent electrons in the descending order arec-ZrO2>ZrYO> ZrCeO2>ZrMgO> ZrCaO.From the above analysis,it can be concluded that the stabilizing degrees of the four stabilizers in the descending order are CaO> MgO>Y2O3>CeO2.

Development of hard X-ray photoelectron SPLEED-based spectrometer applicable for probing of buried magnetic layer valence states

Energy Technology Data Exchange (ETDEWEB)

Kozina, Xeniya, E-mail: kozina@uni-mainz.de [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Ikenaga, Eiji [Japan Synchrotron Radiation Research Institute, SPring-8, Hyogo 679-5198 (Japan); Viol Barbosa, Carlos Eduardo; Ouardi, Siham; Karel, Julie [Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden (Germany); Yamamoto, Masafumi [Division of Electronics for Informatics, Hokkaido University, Sapporo 060-0814 (Japan); Kobayashi, Keisuke [Japan Atomic Energy Agency, SPring-8, Hyogo 679-5148 (Japan); Elmers, Hans Joachim; Schönhense, Gerd [Institut für Physik, Johannes Gutenberg – Universität, 55099 Mainz (Germany); Felser, Claudia [Max-Planck-Institut für Chemische Physik fester Stoffe, 01187 Dresden (Germany)

2016-08-15

Highlights: • A high-voltage compatible spin-HAXPES detector based on SPLEED from W(001) has been developed. • Magnetic properties of a TMR device were studied by core-level photoemission on the Fe 2p{sub 3/2} states. • The developed instrument enabled probing of buried layers in the region of the valence states. - Abstract: A novel design of high-voltage compatible polarimeter for spin-resolved hard X-ray photoelectron spectroscopy (Spin-HAXPES) went into operation at beamline BL09XU of SPring-8 in Hyogo, Japan. The detector is based on the well-established principle of electron diffraction from a W(001) single-crystal at a scattering energy of 103.5 eV. It's special feature is that it can be operated at a high negative bias potential up to 10 kV, necessary to access the HAXPES range. The polarimeter is operated behind a large hemispherical analyzer (Scienta R-4000). It was optimized for high transmission of the transfer optics. A delay-line detector (20 mm dia.) is positioned at the exit plane of the analyzer enabling conventional multichannel intensity spectroscopy simultaneously with single-channel spin analysis. The performance of the combined setup is demonstrated by the spin-resolved data for the valence-region of a FeCo functional layer of a tunneling device, buried beneath 3 nm of oxidic material. The well-structured spin polarization spectrum validates Spin-HAXPES in the valence energy range as powerful method for bulk electronic structure analysis. The spin polarization spectrum exhibits a rich structure, originating from clearly discernible transitions in the majority and minority partial spin spectra.

On triangle meshes with valence dominant vertices

KAUST Repository

Morvan, Jean-Marie

2018-02-16

We study triangulations $\\\\cal T$ defined on a closed disc $X$ satisfying the following condition: In the interior of $X$, the valence of all vertices of $\\\\cal T$ except one of them (the irregular vertex) is $6$. By using a flat singular Riemannian metric adapted to $\\\\cal T$, we prove a uniqueness theorem when the valence of the irregular vertex is not a multiple of $6$. Moreover, for a given integer $k >1$, we exhibit non isomorphic triangulations on $X$ with the same boundary, and with a unique irregular vertex whose valence is $6k$.

On triangle meshes with valence dominant vertices

KAUST Repository

Morvan, Jean-Marie

2018-01-01

We study triangulations $\\cal T$ defined on a closed disc $X$ satisfying the following condition: In the interior of $X$, the valence of all vertices of $\\cal T$ except one of them (the irregular vertex) is $6$. By using a flat singular Riemannian metric adapted to $\\cal T$, we prove a uniqueness theorem when the valence of the irregular vertex is not a multiple of $6$. Moreover, for a given integer $k >1$, we exhibit non isomorphic triangulations on $X$ with the same boundary, and with a unique irregular vertex whose valence is $6k$.

Electron momentum distributions and binding energies for the valence orbitals of hydrogen bromide and hydrogen iodide

International Nuclear Information System (INIS)

Brion, C.E.; McCarthy, I.E.; Suzuki, I.H.; Weigold, E.; Williams, G.R.J.; Bedford, K.L.; Kunz, A.B.; Weidman, R.

1981-12-01

The electron binding energy spectra and momentum distributions have been obtained for the valence orbitals of HBr and HI using noncoplanar symmetric electron coincidence spectroscopy at 1200eV. The weakly bonding inner valence ns orbitals, which have not been previously observed, have their spectroscopic (pole) strength severely split among a number of ion states. For HBr the strength of the main inner valence (ns) transition is 0.42 0.03 whereas for HI it is 0.37 0.04, in close agreement with that observed for the valence s orbitals of the corresponding isoelectronic inert gas atoms. The spectroscopic strength for the two outermost orbitals is found to be close to unity, in agreement with many body Green's function calculations. The measured momentum distributions are compared with several spherically averaged MO momentum distributions, as well as (for HBr) with a Green's function calculation of the generalized overlap amplitude (GOA). The GOA momentum distributions are in excellent agreement with the HBr data, both in shape and relative magnitude. Not all of the MO momentum distributions are in reasonable agreement with the data. Comparison is also made with the calculated momentum distributions for Kr, Br, Xe and I

Theoretical calculations of valence states in Fe-Mo compounds

International Nuclear Information System (INIS)

Estrada, F; Navarro, O; Noverola, H; Suárez, J R; Avignon, M

2014-01-01

The half-metallic ferromagnetic double perovskite compound Sr 2 FeMoO 6 is considered as an important material for spintronic applications. It appears to be fundamental to understand the role of electronic parameters controlling the half-metallic ground state. Fe-Mo double perovskites usually present some degree of Fe/Mo disorder which generally increases with doping. In this work, we study the valence states of Fe-Mo cations in the off-stoichiometric system Sr 2 Fe 1+x Mo 1−x O 6 (−1 ≤ x ≤ 1/3) with disorder. Our results for Fe and Mo valence states are obtained using the Green functions and the renormalization perturbation expansion method. The model is based on a correlated electron picture with localized Fe-spins and conduction Mo-electrons interacting with the local spins via a double-exchange-type mechanism

Social learning modulates the lateralization of emotional valence.

Science.gov (United States)

Shamay-Tsoory, Simone G; Lavidor, Michal; Aharon-Peretz, Judith

2008-08-01

Although neuropsychological studies of lateralization of emotion have emphasized valence (positive vs. negative) or type (basic vs. complex) dimensions, the interaction between the two dimensions has yet to be elucidated. The purpose of the current study was to test the hypothesis that recognition of basic emotions is processed preferentially by the right prefrontal cortex (PFC), whereas recognition of complex social emotions is processed preferentially by the left PFC. Experiment 1 assessed the ability of healthy controls and patients with right and left PFC lesions to recognize basic and complex emotions. Experiment 2 modeled the patient's data of Experiment 1 on healthy participants under lateralized displays of the emotional stimuli. Both experiments support the Type as well as the Valence Hypotheses. However, our findings indicate that the Valence Hypothesis holds for basic but less so for complex emotions. It is suggested that, since social learning overrules the basic preference of valence in the hemispheres, the processing of complex emotions in the hemispheres is less affected by valence.

The uranium valence in the Cs-U-O system: crystal structures and thin layers contribution to the physico-chemical study of grain boundaries in irradiated fuel

International Nuclear Information System (INIS)

Van Den Berghe, S.

2002-01-01

The document is an abstract of a PhD thesis. The PhD thesis investigates the way in which cesium, through its effect on oxygen, modifies the uranium environment and in consequence the valence state of the uranium atom itself. To this end, the crystallographic structure and local uranium environment of several uranium uranates has been determined by Rietveld refinement of neutron and X-ray diffraction data. Thin layers of stoichiometric uranium dioxide were prepared using sputter deposition techniques and used to model interactions on the grain boundaries. They were covered with cesium and exposed to controlled amounts of oxygen, while the uranium valence state was monitored with Ultraviolet Photoelectron Spectroscopy and XPS

Event-related brain potential correlates of words' emotional valence irrespective of arousal and type of task.

Science.gov (United States)

Espuny, Javier; Jiménez-Ortega, Laura; Casado, Pilar; Fondevila, Sabela; Muñoz, Francisco; Hernández-Gutiérrez, David; Martín-Loeches, Manuel

2018-03-23

Many Event-Related brain Potential (ERP) experiments have explored how the two main dimensions of emotion, arousal and valence, affect linguistic processing. However, the heterogeneity of experimental paradigms and materials has led to mixed results. In the present study, we aim to clarify words' emotional valence effects on ERP when arousal is controlled, and determine whether these effects may vary as a function of the type of task performed. For these purposes, we designed an ERP experiment with the valence of words manipulated, and arousal equated across valences. The participants performed two types of task: in one, they had to read aloud each word, written in black on a white background; in the other, they had to name the color of the ink in which each word was written. The results showed the main effects of valence irrespective of task, and no interaction between valence and task. The most marked effects of valence were in response to negative words, which elicited an Early Posterior Negativity (EPN) and a Late Positive Complex (LPC). Our results suggest that, when arousal is controlled, the cognitive information in negative words triggers a 'negativity bias', these being the only words able to elicit emotion-related ERP modulations. Moreover, these modulations are largely unaffected by the types of task explored here. Copyright © 2018 Elsevier B.V. All rights reserved.

Valency and type conversion in CuInSe2 with H2 plasma exposure: A photoemission investigation

International Nuclear Information System (INIS)

Nelson, A.J.; Frigo, S.P.; Rosenberg, R.

1993-01-01

The effect of H 2 plasma exposure on CuInSe 2 was studied by synchrotron radiation soft-x-ray photoemission spectroscopy. The low-power H 2 plasma was generated with a commercial electron cyclotron resonance plasma source using pure H 2 with the plasma exposure being performed at 200 degree C. In situ photoemission measurements were acquired after each plasma exposure in order to observe changes in the valence-band electronic structure as well as changes in the In 4d and Se 3d core lines. The results were correlated in order to relate changes in surface chemistry to the electronic structure. These measurements indicate that the H 2 plasma exposure type converts the CuInSe 2 surface to an n-type surface as well as converting the In +3 valency state to an In +1 valency state

The Relation Between Valence and Arousal in Subjective Experience Varies With Personality and Culture.

Science.gov (United States)

Kuppens, Peter; Tuerlinckx, Francis; Yik, Michelle; Koval, Peter; Coosemans, Joachim; Zeng, Kevin J; Russell, James A

2017-08-01

While in general arousal increases with positive or negative valence (a so-called V-shaped relation), there are large differences among individuals in how these two fundamental dimensions of affect are related in people's experience. In two studies, we examined two possible sources of this variation: personality and culture. In Study 1, participants (Belgian university students) recalled a recent event that was characterized by high or low valence or arousal and reported on their feelings and their personality in terms of the Five-Factor Model. In Study 2, participants from Canada, China/Hong Kong, Japan, Korea, and Spain reported on their feelings in a thin slice of time and on their personality. In Study 1, we replicated the V-shape as characterizing the relation between valence and arousal, and identified personality correlates of experiencing particular valence-arousal combinations. In Study 2, we documented how the V-shaped relation varied as a function of Western versus Eastern cultural background and personality. The results showed that the steepness of the V-shaped relation between valence and arousal increases with Extraversion within cultures, and with a West-East distinction between cultures. Implications for the personality-emotion link and research on cultural differences in affect are discussed. © 2016 Wiley Periodicals, Inc.

Mnemonic transmission, social contagion, and emergence of collective memory: Influence of emotional valence, group structure, and information distribution.

Science.gov (United States)

Choi, Hae-Yoon; Kensinger, Elizabeth A; Rajaram, Suparna

2017-09-01

Social transmission of memory and its consequence on collective memory have generated enduring interdisciplinary interest because of their widespread significance in interpersonal, sociocultural, and political arenas. We tested the influence of 3 key factors-emotional salience of information, group structure, and information distribution-on mnemonic transmission, social contagion, and collective memory. Participants individually studied emotionally salient (negative or positive) and nonemotional (neutral) picture-word pairs that were completely shared, partially shared, or unshared within participant triads, and then completed 3 consecutive recalls in 1 of 3 conditions: individual-individual-individual (control), collaborative-collaborative (identical group; insular structure)-individual, and collaborative-collaborative (reconfigured group; diverse structure)-individual. Collaboration enhanced negative memories especially in insular group structure and especially for shared information, and promoted collective forgetting of positive memories. Diverse group structure reduced this negativity effect. Unequally distributed information led to social contagion that creates false memories; diverse structure propagated a greater variety of false memories whereas insular structure promoted confidence in false recognition and false collective memory. A simultaneous assessment of network structure, information distribution, and emotional valence breaks new ground to specify how network structure shapes the spread of negative memories and false memories, and the emergence of collective memory. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Neural correlates of emotional recognition memory in schizophrenia: effects of valence and arousal.

Science.gov (United States)

Lakis, Nadia; Jiménez, José A; Mancini-Marïe, Adham; Stip, Emmanuel; Lavoie, Marc E; Mendrek, Adrianna

2011-12-30

Schizophrenia patients are often impaired in their memory for emotional events compared with healthy subjects. Investigations of the neural correlates of emotional memory in schizophrenia patients are scarce in the literature. The present study aimed to compare cerebral activations in schizophrenia patients and healthy controls during memory retrieval of emotional images that varied in both valence and arousal. In a study with functional magnetic resonance imaging, 37 schizophrenia patients were compared with 37 healthy participants while performing a yes/no recognition paradigm with positive, negative (differing in arousal intensity) and neutral images. Schizophrenia patients performed worse than healthy controls in all experimental conditions. They showed less cerebral activation in limbic and prefrontal regions than controls during retrieval of negatively valenced stimuli, but had a similar pattern of brain activation compared with controls during retrieval of positively valenced stimuli (particularly in the high arousal condition) in the cerebellum, temporal lobe and prefrontal cortex. Both groups demonstrated increased brain activations in the high relative to low arousing conditions. Our results suggest atypical brain function during retrieval of negative pictures, but intact functional circuitry of positive affect during episodic memory retrieval in schizophrenia patients. The arousal data revealed that schizophrenia patients closely resemble the control group at both the behavioral and neurofunctional level. 2011 Elsevier Ireland Ltd. All rights reserved.

Valence control of cobalt oxide thin films by annealing atmosphere

Energy Technology Data Exchange (ETDEWEB)

Wang Shijing [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 100083 (China); Zhang Boping, E-mail: bpzhang@ustb.edu.cn [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 100083 (China); Zhao Cuihua; Li Songjie; Zhang Meixia; Yan Liping [School of Materials Science and Engineering, University of Science and Technology Beijing, No. 30 Xueyuan Road, Beijing 100083 (China)

2011-02-01

The cobalt oxide (CoO and Co{sub 3}O{sub 4}) thin films were successfully prepared using a spin-coating technique by a chemical solution method with CH{sub 3}OCH{sub 2}CH{sub 2}OH and Co(NO{sub 3}){sub 2}.6H{sub 2}O as starting materials. The grayish cobalt oxide films had uniform crystalline grains with less than 50 nm in diameter. The phase structure is able to tailor by controlling the annealing atmosphere and temperature, in which Co{sub 3}O{sub 4} thin film was obtained by annealing in air at 300-600, and N{sub 2} at 300, and transferred to CoO thin film by raising annealing temperature in N{sub 2}. The fitted X-ray photoelectron spectroscopy (XPS) spectra of the Co2p electrons are distinguishable from different valence states of cobalt oxide especially for their satellite structure. The valence control of cobalt oxide thin films by annealing atmosphere contributes to the tailored optical absorption property.

Exchange Coupling Interactions from the Density Matrix Renormalization Group and N-Electron Valence Perturbation Theory: Application to a Biomimetic Mixed-Valence Manganese Complex.

Science.gov (United States)

Roemelt, Michael; Krewald, Vera; Pantazis, Dimitrios A

2018-01-09

The accurate description of magnetic level energetics in oligonuclear exchange-coupled transition-metal complexes remains a formidable challenge for quantum chemistry. The density matrix renormalization group (DMRG) brings such systems for the first time easily within reach of multireference wave function methods by enabling the use of unprecedentedly large active spaces. But does this guarantee systematic improvement in predictive ability and, if so, under which conditions? We identify operational parameters in the use of DMRG using as a test system an experimentally characterized mixed-valence bis-μ-oxo/μ-acetato Mn(III,IV) dimer, a model for the oxygen-evolving complex of photosystem II. A complete active space of all metal 3d and bridge 2p orbitals proved to be the smallest meaningful starting point; this is readily accessible with DMRG and greatly improves on the unrealistic metal-only configuration interaction or complete active space self-consistent field (CASSCF) values. Orbital optimization is critical for stabilizing the antiferromagnetic state, while a state-averaged approach over all spin states involved is required to avoid artificial deviations from isotropic behavior that are associated with state-specific calculations. Selective inclusion of localized orbital subspaces enables probing the relative contributions of different ligands and distinct superexchange pathways. Overall, however, full-valence DMRG-CASSCF calculations fall short of providing a quantitative description of the exchange coupling owing to insufficient recovery of dynamic correlation. Quantitatively accurate results can be achieved through a DMRG implementation of second order N-electron valence perturbation theory (NEVPT2) in conjunction with a full-valence metal and ligand active space. Perspectives for future applications of DMRG-CASSCF/NEVPT2 to exchange coupling in oligonuclear clusters are discussed.

Ground state and elementary excitations of a model valence-fluctuation system

International Nuclear Information System (INIS)

Brandow, B.H.

1979-01-01

The nature of the valence fluctuation problem is described, and motivations are given for an Anderson-lattice model Hamiltonian. A simple trial wave function is posed for the ground state, and the variational problem is solved. This demonstrates clearly that there is no Kondo-like divergence; the present concentrated Kondo problem is thus more simple mathematically than the sngle-impurity problem. Elementary excitations are studies by the Green's function techniques of Zubarev and Hubbard. Quenching of local moments and a large specific heat are found at low temperatures. The quasi-particle spectrum exhibits a gap, but epsilon/sub F/ does not lie in this gap. The insulation-like feature of SmB 6 , SmS, and TmSe at very low temperatures is explained in terms of a strongly reduced mobility for states near the gap, and reasons are given why this feature is not observed in other valence-fluctuation compounds. 73 references

Valence-band splitting energies in wurtzite InP nanowires: Photoluminescence spectroscopy and ab initio calculations

Science.gov (United States)

Gadret, E. G.; Dias, G. O.; Dacal, L. C. O.; de Lima, M. M., Jr.; Ruffo, C. V. R. S.; Iikawa, F.; Brasil, M. J. S. P.; Chiaramonte, T.; Cotta, M. A.; Tizei, L. H. G.; Ugarte, D.; Cantarero, A.

2010-09-01

We investigated experimentally and theoretically the valence-band structure of wurtzite InP nanowires. The wurtzite phase, which usually is not stable for III-V phosphide compounds, has been observed in InP nanowires. We present results on the electronic properties of these nanowires using the photoluminescence excitation technique. Spectra from an ensemble of nanowires show three clear absorption edges separated by 44 meV and 143 meV, respectively. The band edges are attributed to excitonic absorptions involving three distinct valence-bands labeled: A, B, and C. Theoretical results based on “ab initio” calculation gives corresponding valence-band energy separations of 50 meV and 200 meV, respectively, which are in good agreement with the experimental results.

Valence electron structure and properties of the ZrO2

Institute of Scientific and Technical Information of China (English)

2008-01-01

To reveal the properties of ZrO2 at the atom and electron levels, the valence elec- tron structures of three ZrO2 phases were analyzed on the basis of the empirical electron theory of solids and molecules. The results showed that the hybridization levels of Zr and O atoms in the m-ZrO2 were the same as those in the t-ZrO2, while those in the c-ZrO2 rose markedly. The electron numbers and bond energies on the strongest covalent bonds in the m-ZrO2 phase were the greatest, the values were 0.901106 and 157.5933 kJ/mol, respectively. Those in the t-ZrO2 phase took second place, which were 0.722182 and 123.9304 kJ/mol, and those in the c-ZrO2 phase were the smallest, which were 0.469323 and 79.0289 kJ/mol. According to the product of the bond energy on the strongest covalent bond and equivalent bond number (this value reflected the crystal cohesive energy), the order from the greatness to smallness was the c-ZrO2> t-ZrO2 > m-ZrO2. This showed that the m-phase bonds were the tightest, their energy was the smallest, the crystal cohe- sive energy of the m-phase was the largest, and the m-phase existed most stably at room temperature. So it must need energy or higher temperature to take apart the stronger covalent bonds to form a new phase.

Valence electron structure and properties of the ZrO2

Institute of Scientific and Technical Information of China (English)

LI JinPing; MENG SongHe; HAN JieCai; ZHANG XingHong

2008-01-01

To reveal the properties of ZrO2 at the atom and electron levels, the valence elec-tron structures of three ZrO2 phases were analyzed on the basis of the empirical electron theory of solids and molecules. The results showed that the hybridization levels of Zr and O atoms in the m-ZrO2 were the same as those in the t-ZrO2, while those in the c-ZrO2 rose markedly. The electron numbers and bond energies on the strongest covalent bonds in the m-ZrO2 phase were the greatest, the values were 0.901106 and 157.5933 kJ/mol, respectively. Those in the t-ZrO2 phase took second place, which were 0.722182 and 123.9304 kJ/mol, and those in the c-ZrO2 phase were the smallest, which were 0.469323 and 79.0289 kJ/mol. According to the product of the bond energy on the strongest covalent bond and equivalent bond number (this value reflected the crystal cohesive energy), the order from the greatness to smallness was the c-ZrO2 t-ZrO2 m-ZrO2. This showed that the m-phase bonds were the tightest, their energy was the smallest, the crystal cohe-sive energy of the m-phase was the largest, and the m-phase existed most stably at room temperature. So it must need energy or higher temperature to take apart the stronger covalent bonds to form a new phase.

Theory for the mixed-valence state

International Nuclear Information System (INIS)

Varma, C.M.

1979-01-01

A theory is presented which explains why mixed-valence compounds behave as two component Fermi liquids, and why TmSe orders magnetically while the other known mixed-valence compounds do not. The variation of Tsub(N) and the field Hsub(T) to obtain ferromagnetic alignment with changing Tm 2+ /Tm 3+ ratio is quantitatively explained. For Tm 2+ concentration > = 0.3, TmSe is predicted to order ferromagnetically

Music, emotion, and time perception: the influence of subjective emotional valence and arousal?

Science.gov (United States)

Droit-Volet, Sylvie; Ramos, Danilo; Bueno, José L. O.; Bigand, Emmanuel

2013-01-01

The present study used a temporal bisection task with short (2 s) stimulus durations to investigate the effect on time estimation of several musical parameters associated with emotional changes in affective valence and arousal. In order to manipulate the positive and negative valence of music, Experiments 1 and 2 contrasted the effect of musical structure with pieces played normally and backwards, which were judged to be pleasant and unpleasant, respectively. This effect of valence was combined with a subjective arousal effect by changing the tempo of the musical pieces (fast vs. slow) (Experiment 1) or their instrumentation (orchestral vs. piano pieces). The musical pieces were indeed judged more arousing with a fast than with a slow tempo and with an orchestral than with a piano timbre. In Experiment 3, affective valence was also tested by contrasting the effect of tonal (pleasant) vs. atonal (unpleasant) versions of the same musical pieces. The results showed that the effect of tempo in music, associated with a subjective arousal effect, was the major factor that produced time distortions with time being judged longer for fast than for slow tempi. When the tempo was held constant, no significant effect of timbre on the time judgment was found although the orchestral music was judged to be more arousing than the piano music. Nevertheless, emotional valence did modulate the tempo effect on time perception, the pleasant music being judged shorter than the unpleasant music. PMID:23882233

Music, Emotion and Time Perception: The influence of subjective emotional valence and arousal?

Directory of Open Access Journals (Sweden)

SYLVIE eDROIT-VOLET

2013-07-01

Full Text Available The present study used a temporal bisection task with short (< 2 s and long (> 2 s stimulus durations to investigate the effect on time estimation of several musical parameters associated with emotional changes in affective valence and arousal. In order to manipulate the positive and negative valence of music, Experiments 1 and 2 contrasted the effect of musical structure with pieces played normally and backwards, which were judged to be pleasant and unpleasant, respectively. This effect of valence was combined with a subjective arousal effect by changing the tempo of the musical pieces (fast vs. slow (Experiment 1 or their instrumentation (orchestral vs. piano pieces. The musical pieces were indeed judged more arousing with a fast than with a slow tempo and with an orchestral than with a piano timbre. In Experiment 3, affective valence was also tested by contrasting the effect of tonal (pleasant versus atonal (unpleasant versions of the same musical pieces. The results showed that the effect of tempo in music, associated with a subjective arousal effect, was the major factor that produced time distortions with time being judged longer for fast than for slow tempi. When the tempo was held constant, no significant effect of timbre on the time judgment was found although the orchestral music was judged to be more arousing than the piano music. Nevertheless, emotional valence did modulate the tempo effect on time perception, the pleasant music being judged shorter than the unpleasant music.

Music, emotion, and time perception: the influence of subjective emotional valence and arousal?

Science.gov (United States)

Droit-Volet, Sylvie; Ramos, Danilo; Bueno, José L O; Bigand, Emmanuel

2013-01-01

The present study used a temporal bisection task with short (2 s) stimulus durations to investigate the effect on time estimation of several musical parameters associated with emotional changes in affective valence and arousal. In order to manipulate the positive and negative valence of music, Experiments 1 and 2 contrasted the effect of musical structure with pieces played normally and backwards, which were judged to be pleasant and unpleasant, respectively. This effect of valence was combined with a subjective arousal effect by changing the tempo of the musical pieces (fast vs. slow) (Experiment 1) or their instrumentation (orchestral vs. piano pieces). The musical pieces were indeed judged more arousing with a fast than with a slow tempo and with an orchestral than with a piano timbre. In Experiment 3, affective valence was also tested by contrasting the effect of tonal (pleasant) vs. atonal (unpleasant) versions of the same musical pieces. The results showed that the effect of tempo in music, associated with a subjective arousal effect, was the major factor that produced time distortions with time being judged longer for fast than for slow tempi. When the tempo was held constant, no significant effect of timbre on the time judgment was found although the orchestral music was judged to be more arousing than the piano music. Nevertheless, emotional valence did modulate the tempo effect on time perception, the pleasant music being judged shorter than the unpleasant music.

Determination of valence band parameters in ZnTe

Energy Technology Data Exchange (ETDEWEB)

Froehlich, D.; Noethe, A.; Reimann, K. (Duesseldorf Univ. (Germany, F.R.). Physikalisches Inst. - Lehrstuhl 2)

1984-10-01

The fine structure of the 2P exciton in ZnTe is studied by two-photon-absorption. The energy splitting into four states, caused by the envelope-hole coupling, allows the determination of the Luttinger parameters ..gamma../sub 2/ and ..gamma../sub 3/, which describe the complex valence band. ..gamma../sub 2/ = 0.8 and ..gamma../sub 3/ = 1.7 are obtained. These values are compared to results of other experiments mainly on 1S excitons.

High energy pp and anti-pp elastic scattering in nucleon valence core model

International Nuclear Information System (INIS)

Islam, M.M.; Fearnley, T.

1986-01-01

Connection between the valence core model and the effective QCD models of nucleon structure is pointed out. Also, implication of recent anti-pp differential cross section measurements at 53 GeV on our previous calculations is discussed

Metal-like Band Structures of Ultrathin Si {111} and {112} Surface Layers Revealed through Density Functional Theory Calculations.

Science.gov (United States)

Tan, Chih-Shan; Huang, Michael H

2017-09-04

Density functional theory calculations have been performed on Si (100), (110), (111), and (112) planes with tunable number of planes for evaluation of their band structures and density of states profiles. The purpose is to see whether silicon can exhibit facet-dependent properties derived from the presence of a thin surface layer having different band structures. No changes have been observed for single to multiple layers of Si (100) and (110) planes with a consistent band gap between the valence band and the conduction band. However, for 1, 2, 4, and 5 Si (111) and (112) planes, metal-like band structures were obtained with continuous density of states going from the valence band to the conduction band. For 3, 6, and more Si (111) planes, as well as 3 and 6 Si (112) planes, the same band structure as that seen for Si (100) and (110) planes has been obtained. Thus, beyond a layer thickness of five Si (111) planes at ≈1.6 nm, normal semiconductor behavior can be expected. The emergence of metal-like band structures for the Si (111) and (112) planes are related to variation in Si-Si bond length and bond distortion plus 3s and 3p orbital electron contributions in the band structure. This work predicts possession of facet-dependent electrical properties of silicon with consequences in FinFET transistor design. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

In search for an optimal methodology to calculate the valence electron affinities of temporary anions.

Science.gov (United States)

Puiatti, Marcelo; Vera, D Mariano A; Pierini, Adriana B

2009-10-28

Recently, we have proposed an approach for finding the valence anion ground state, based on the stabilization exerted by a polar solvent; the methodology used standard DFT methods and relatively inexpensive basis sets and yielded correct electron affinity (EA) values by gradually decreasing the dielectric constant of the medium. In order to address the overall performance of the new methodology, to find the best conditions for stabilizing the valence state and to evaluate its scope and limitations, we gathered a pool of 60 molecules, 25 of them bearing the conventional valence state as the ground anion and 35 for which the lowest anion state found holds the extra electron in a diffuse orbital around the molecule (non valence state). The results obtained by testing this representative set suggest a very good performance for most species having an experimental EA less negative than -3.0 eV; the correlation at the B3LYP/6-311+G(2df,p) level being y = 1.01x + 0.06, with a correlation index of 0.985. As an alternative, the time dependent DFT (TD-DFT) approach was also tested with both B3LYP and PBE0 functionals. The methodology we proposed shows a comparable or better accuracy with respect to TD-DFT, although the TD-DFT approach with the PBE0 functional is suggested as a suitable estimate for species with the most negative EAs (ca.-2.5 to -3.5 eV), for which stabilization strategies can hardly reach the valence state. As an application, a pool of 8 compounds of key biological interest with EAs which remain unknown or unclear were predicted using the new methodology.

Effects of self-relevant cues and cue valence on autobiographical memory specificity in dysphoria.

Science.gov (United States)

Matsumoto, Noboru; Mochizuki, Satoshi

2017-04-01

Reduced autobiographical memory specificity (rAMS) is a characteristic memory bias observed in depression. To corroborate the capture hypothesis in the CaRFAX (capture and rumination, functional avoidance, executive capacity and control) model, we investigated the effects of self-relevant cues and cue valence on rAMS using an adapted Autobiographical Memory Test conducted with a nonclinical population. Hierarchical linear modelling indicated that the main effects of depression and self-relevant cues elicited rAMS. Moreover, the three-way interaction among valence, self-relevance, and depression scores was significant. A simple slope test revealed that dysphoric participants experienced rAMS in response to highly self-relevant positive cues and low self-relevant negative cues. These results partially supported the capture hypothesis in nonclinical dysphoria. It is important to consider cue valence in future studies examining the capture hypothesis.

A density functional theory investigation of the electronic structure and spin moments of magnetite

KAUST Repository

Noh, Junghyun

2014-08-01

We present the results of density functional theory (DFT) calculations on magnetite, Fe3O4, which has been recently considered as electrode in the emerging field of organic spintronics. Given the nature of the potential applications, we evaluated the magnetite room-temperature cubic phase in terms of structural, electronic, and magnetic properties. We considered GGA (PBE), GGA + U (PBE + U), and range-separated hybrid (HSE06 and HSE(15%)) functionals. Calculations using HSE06 and HSE(15%) functionals underline the impact that inclusion of exact exchange has on the electronic structure. While the modulation of the band gap with exact exchange has been seen in numerous situations, the dramatic change in the valence band nature and states near the Fermi level has major implications for even a qualitative interpretation of the DFT results. We find that HSE06 leads to highly localized states below the Fermi level while HSE(15%) and PBE + U result in delocalized states around the Fermi level. The significant differences in local magnetic moments and atomic charges indicate that describing room-temperature bulk materials, surfaces and interfaces may require different functionals than their low-temperature counterparts.

A density functional theory investigation of the electronic structure and spin moments of magnetite

KAUST Repository

Noh, Junghyun; Osman, Osman I; Aziz, Saadullah G; Winget, Paul; Bredas, Jean-Luc

2014-01-01

We present the results of density functional theory (DFT) calculations on magnetite, Fe3O4, which has been recently considered as electrode in the emerging field of organic spintronics. Given the nature of the potential applications, we evaluated the magnetite room-temperature cubic phase in terms of structural, electronic, and magnetic properties. We considered GGA (PBE), GGA + U (PBE + U), and range-separated hybrid (HSE06 and HSE(15%)) functionals. Calculations using HSE06 and HSE(15%) functionals underline the impact that inclusion of exact exchange has on the electronic structure. While the modulation of the band gap with exact exchange has been seen in numerous situations, the dramatic change in the valence band nature and states near the Fermi level has major implications for even a qualitative interpretation of the DFT results. We find that HSE06 leads to highly localized states below the Fermi level while HSE(15%) and PBE + U result in delocalized states around the Fermi level. The significant differences in local magnetic moments and atomic charges indicate that describing room-temperature bulk materials, surfaces and interfaces may require different functionals than their low-temperature counterparts.

The olfactory tubercle encodes odor valence in behaving mice.

Science.gov (United States)

Gadziola, Marie A; Tylicki, Kate A; Christian, Diana L; Wesson, Daniel W

2015-03-18

Sensory information acquires meaning to adaptively guide behaviors. Despite odors mediating a number of vital behaviors, the components of the olfactory system responsible for assigning meaning to odors remain unclear. The olfactory tubercle (OT), a ventral striatum structure that receives monosynaptic input from the olfactory bulb, is uniquely positioned to transform odor information into behaviorally relevant neural codes. No information is available, however, on the coding of odors among OT neurons in behaving animals. In recordings from mice engaged in an odor discrimination task, we report that the firing rate of OT neurons robustly and flexibly encodes the valence of conditioned odors over identity, with rewarded odors evoking greater firing rates. This coding of rewarded odors occurs before behavioral decisions and represents subsequent behavioral responses. We predict that the OT is an essential region whereby odor valence is encoded in the mammalian brain to guide goal-directed behaviors. Copyright © 2015 the authors 0270-6474/15/354515-13$15.00/0.

Accounting for many-body correlation effects in the calculation of the valence band photoelectron emission spectra of ferromagnets

International Nuclear Information System (INIS)

Minar, J.; Chadov, S.; Ebert, H.; Chioncel, L.; Lichtenstein, A.; De Nadai, C.; Brookes, N.B.

2005-01-01

The influence of dynamical correlation effects on the valence band photoelectron emission of ferromagnetic Fe, Co and Ni has been investigated. Angle-resolved as well as angle-integrated valence band photoelectron emission spectra were calculated on the basis of the one-particle Green's function, which was obtained by using the fully relativistic Korringa-Kohn-Rostoker method. The correlation effects have been included in terms of the electronic self-energy which was calculated self-consistently within Dynamical Mean-Field Theory (DMFT). In addition a theoretical approach to calculate high-energy angle-resolved valence band photoelectron emission spectra is presented

Core and Valence Structures in K beta X-ray Emission Spectra of Chromium Materials

NARCIS (Netherlands)

Torres Deluigi, Maria; de Groot, Frank M. F.; Lopez-Diaz, Gaston; Tirao, German; Stutz, Guillermo; Riveros de la Vega, Jose

2014-01-01

We analyze the core and valence transitions in chromium in a series of materials with a number of different ligands and including the oxidation states: Cr-II, Cr-III, Cr-IV, and Cr-VI. To study the core-to-core transitions we employ the CTM4XAS program and investigate the shapes, widths,

Valence-Dependent Belief Updating: Computational Validation

Directory of Open Access Journals (Sweden)

Bojana Kuzmanovic

2017-06-01

Full Text Available People tend to update beliefs about their future outcomes in a valence-dependent way: they are likely to incorporate good news and to neglect bad news. However, belief formation is a complex process which depends not only on motivational factors such as the desire for favorable conclusions, but also on multiple cognitive variables such as prior beliefs, knowledge about personal vulnerabilities and resources, and the size of the probabilities and estimation errors. Thus, we applied computational modeling in order to test for valence-induced biases in updating while formally controlling for relevant cognitive factors. We compared biased and unbiased Bayesian models of belief updating, and specified alternative models based on reinforcement learning. The experiment consisted of 80 trials with 80 different adverse future life events. In each trial, participants estimated the base rate of one of these events and estimated their own risk of experiencing the event before and after being confronted with the actual base rate. Belief updates corresponded to the difference between the two self-risk estimates. Valence-dependent updating was assessed by comparing trials with good news (better-than-expected base rates with trials with bad news (worse-than-expected base rates. After receiving bad relative to good news, participants' updates were smaller and deviated more strongly from rational Bayesian predictions, indicating a valence-induced bias. Model comparison revealed that the biased (i.e., optimistic Bayesian model of belief updating better accounted for data than the unbiased (i.e., rational Bayesian model, confirming that the valence of the new information influenced the amount of updating. Moreover, alternative computational modeling based on reinforcement learning demonstrated higher learning rates for good than for bad news, as well as a moderating role of personal knowledge. Finally, in this specific experimental context, the approach based on

Emotion and language: Valence and arousal affect word recognition

Science.gov (United States)

Brysbaert, Marc; Warriner, Amy Beth

2014-01-01

Emotion influences most aspects of cognition and behavior, but emotional factors are conspicuously absent from current models of word recognition. The influence of emotion on word recognition has mostly been reported in prior studies on the automatic vigilance for negative stimuli, but the precise nature of this relationship is unclear. Various models of automatic vigilance have claimed that the effect of valence on response times is categorical, an inverted-U, or interactive with arousal. The present study used a sample of 12,658 words, and included many lexical and semantic control factors, to determine the precise nature of the effects of arousal and valence on word recognition. Converging empirical patterns observed in word-level and trial-level data from lexical decision and naming indicate that valence and arousal exert independent monotonic effects: Negative words are recognized more slowly than positive words, and arousing words are recognized more slowly than calming words. Valence explained about 2% of the variance in word recognition latencies, whereas the effect of arousal was smaller. Valence and arousal do not interact, but both interact with word frequency, such that valence and arousal exert larger effects among low-frequency words than among high-frequency words. These results necessitate a new model of affective word processing whereby the degree of negativity monotonically and independently predicts the speed of responding. This research also demonstrates that incorporating emotional factors, especially valence, improves the performance of models of word recognition. PMID:24490848

Screening possible solid electrolytes by calculating the conduction pathways using Bond Valence method

Science.gov (United States)

Gao, Jian; Chu, Geng; He, Meng; Zhang, Shu; Xiao, RuiJuan; Li, Hong; Chen, LiQuan

2014-08-01

Inorganic solid electrolytes have distinguished advantages in terms of safety and stability, and are promising to substitute for conventional organic liquid electrolytes. However, low ionic conductivity of typical candidates is the key problem. As connective diffusion path is the prerequisite for high performance, we screen for possible solid electrolytes from the 2004 International Centre for Diffraction Data (ICDD) database by calculating conduction pathways using Bond Valence (BV) method. There are 109846 inorganic crystals in the 2004 ICDD database, and 5295 of them contain lithium. Except for those with toxic, radioactive, rare, or variable valence elements, 1380 materials are candidates for solid electrolytes. The rationality of the BV method is approved by comparing the existing solid electrolytes' conduction pathways we had calculated with those from experiments or first principle calculations. The implication for doping and substitution, two important ways to improve the conductivity, is also discussed. Among them Li2CO3 is selected for a detailed comparison, and the pathway is reproduced well with that based on the density functional studies. To reveal the correlation between connectivity of pathways and conductivity, α/ γ-LiAlO2 and Li2CO3 are investigated by the impedance spectrum as an example, and many experimental and theoretical studies are in process to indicate the relationship between property and structure. The BV method can calculate one material within a few minutes, providing an efficient way to lock onto targets from abundant data, and to investigate the structure-property relationship systematically.

A Comparison of the Valence Band Structure of Bulk and Epitaxial GeTe-based Diluted Magnetic Semiconductors

International Nuclear Information System (INIS)

Pietrzyk, M.A.; Kowalski, B.J.; Orlowski, B.A.; Knoff, W.; Story, T.; Dobrowolski, W.; Slynko, V.E.; Slynko, E.I.; Johnson, R.L.

2010-01-01

In this work we present a comparison of the experimental results, which have been obtained by the resonant photoelectron spectroscopy for a set of selected diluted magnetic semiconductors based on GeTe, doped with manganese. The photoemission spectra are acquired for the photon energy range of 40-60 eV, corresponding to the Mn 3p → 3d resonances. The spectral features related to Mn 3d states are revealed in the emission from the valence band. The Mn 3d states contribution manifests itself in the whole valence band with a maximum at the binding energy of 3.8 eV. (authors)

Valenced cues and contexts have different effects on event-based prospective memory.

Science.gov (United States)

Graf, Peter; Yu, Martin

2015-01-01

This study examined the separate influence and joint influences on event-based prospective memory task performance due to the valence of cues and the valence of contexts. We manipulated the valence of cues and contexts with pictures from the International Affective Picture System. The participants, undergraduate students, showed higher performance when neutral compared to valenced pictures were used for cueing prospective memory. In addition, neutral pictures were more effective as cues when they occurred in a valenced context than in the context of neutral pictures, but the effectiveness of valenced cues did not vary across contexts that differed in valence. The finding of an interaction between cue and context valence indicates that their respective influence on event-based prospective memory task performance cannot be understood in isolation from each other. Our findings are not consistent with by the prevailing view which holds that the scope of attention is broadened and narrowed, respectively, by positively and negatively valenced stimuli. Instead, our findings are more supportive of the recent proposal that the scope of attention is determined by the motivational intensity associated with valenced stimuli. Consistent with this proposal, we speculate that the motivational intensity associated with different retrieval cues determines the scope of attention, that contexts with different valence values determine participants' task engagement, and that prospective memory task performance is determined jointly by attention scope and task engagement.

Valenced cues and contexts have different effects on event-based prospective memory.

Directory of Open Access Journals (Sweden)

Peter Graf

Full Text Available This study examined the separate influence and joint influences on event-based prospective memory task performance due to the valence of cues and the valence of contexts. We manipulated the valence of cues and contexts with pictures from the International Affective Picture System. The participants, undergraduate students, showed higher performance when neutral compared to valenced pictures were used for cueing prospective memory. In addition, neutral pictures were more effective as cues when they occurred in a valenced context than in the context of neutral pictures, but the effectiveness of valenced cues did not vary across contexts that differed in valence. The finding of an interaction between cue and context valence indicates that their respective influence on event-based prospective memory task performance cannot be understood in isolation from each other. Our findings are not consistent with by the prevailing view which holds that the scope of attention is broadened and narrowed, respectively, by positively and negatively valenced stimuli. Instead, our findings are more supportive of the recent proposal that the scope of attention is determined by the motivational intensity associated with valenced stimuli. Consistent with this proposal, we speculate that the motivational intensity associated with different retrieval cues determines the scope of attention, that contexts with different valence values determine participants' task engagement, and that prospective memory task performance is determined jointly by attention scope and task engagement.

Ground-state structures of Hafnium clusters

Energy Technology Data Exchange (ETDEWEB)

Ng, Wei Chun; Yoon, Tiem Leong [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Lim, Thong Leng [Faculty of Engineering and Technoloty, Multimedia University, Melaca Campus, 75450 Melaka (Malaysia)

2015-04-24

Hafnium (Hf) is a very large tetra-valence d-block element which is able to form relatively long covalent bond. Researchers are interested to search for substitution to silicon in the semi-conductor industry. We attempt to obtain the ground-state structures of small Hf clusters at both empirical and density-functional theory (DFT) levels. For calculations at the empirical level, charge-optimized many-body functional potential (COMB) is used. The lowest-energy structures are obtained via a novel global-minimum search algorithm known as parallel tempering Monte-Carlo Basin-Hopping and Genetic Algorithm (PTMBHGA). The virtue of using COMB potential for Hf cluster calculation lies in the fact that by including the charge optimization at the valence shells, we can encourage the formation of proper bond hybridization, and thus getting the correct bond order. The obtained structures are further optimized using DFT to ensure a close proximity to the ground-state.

Structural and magnetic properties of Ba2LuMoO6: a valence bond glass.

Science.gov (United States)

Coomer, Fiona C; Cussen, Edmund J

2013-02-27

We report here the synthesis of the site ordered double perovskite Ba(2)LuMoO(6). Rietveld refinement of room temperature powder x-ray diffraction measurements indicates that it crystallizes in the cubic space group Fm3m, with a = 8.3265(1) Å. Powder neutron diffraction data indicate that, unusually, this cubic symmetry is maintained down to 2 K, with [Formula: see text], Mo(5+) ions situated on the frustrated face-centred cubic lattice. Despite dc-susceptibility measurements showing Curie-Weiss behaviour with strong antiferromagnetic interactions at T ≥ 200 K, there is no evidence of long range magnetic ordering at 2 K. At T ≤ 50 K, susceptibility measurements indicate a loss in moment to ∼18% of the expected value, and there is a corresponding loss in the magnitude of the magnetic exchange. The structural and magnetic properties of this compound are compared with the related compound Ba(2)YMoO(6), which is a valence bond glass.

Surface-site-selective study of valence electronic structures of clean Si(100)-2x1 using Si-L23VV Auger electron-Si-2p photoelectron coincidence spectroscopy

International Nuclear Information System (INIS)

Kakiuchi, Takuhiro; Nagaoka, Shinichi; Hashimoto, Shogo; Fujita, Narihiko; Tanaka, Masatoshi; Mase, Kazuhiko

2010-01-01

Valence electronic structures of a clean Si(100)-2x1 surface are investigated in a surface-site-selective way using Si-L 23 VV Auger electron-Si-2p photoelectron coincidence spectroscopy. The Si-L 23 VV Auger electron spectra measured in coincidence with Si-2p photoelectrons emitted from the Si up-atoms or Si 2nd-layer of Si(100)-2x1 suggest that the position where the highest density of valence electronic states located in the vicinity of the Si up-atoms is shifted by 0.8 eV towards lower binding energy relative to that in the vicinity of the Si 2nd-layer. Furthermore, the valence band maximum in the vicinity of the Si up-atoms is indicated to be shifted by 0.1 eV towards lower binding energy relative to that in the vicinity of the Si 2nd-layer. These results are direct evidence of the transfer of negative charge from the Si 2nd-layer to the Si up-atoms. (author)

Decoding emotional valence from electroencephalographic rhythmic activity.

Science.gov (United States)

Celikkanat, Hande; Moriya, Hiroki; Ogawa, Takeshi; Kauppi, Jukka-Pekka; Kawanabe, Motoaki; Hyvarinen, Aapo

2017-07-01

We attempt to decode emotional valence from electroencephalographic rhythmic activity in a naturalistic setting. We employ a data-driven method developed in a previous study, Spectral Linear Discriminant Analysis, to discover the relationships between the classification task and independent neuronal sources, optimally utilizing multiple frequency bands. A detailed investigation of the classifier provides insight into the neuronal sources related with emotional valence, and the individual differences of the subjects in processing emotions. Our findings show: (1) sources whose locations are similar across subjects are consistently involved in emotional responses, with the involvement of parietal sources being especially significant, and (2) even though the locations of the involved neuronal sources are consistent, subjects can display highly varying degrees of valence-related EEG activity in the sources.

Breakdown of rotational symmetry at semiconductor interfaces; a microscopic description of valence subband mixing

International Nuclear Information System (INIS)

Cortez, S.; Krebs, O.; Voisin, P.

2000-01-01

The recently discovered in-plane optical anisotropy of [001]-grown quantum wells offers a new theoretical and experimental insight into the electronic properties of semiconductor interfaces. We first discuss the coupling of X and Y valence bands due to the breakdown of rotation inversion symmetry at a semiconductor hetero-interface, with special attention to its dependence on effective parameters such as valence band offset. The intracell localization of Bloch functions is explained from simple theoretical arguments and evaluated numerically from a pseudo-potential microscopic model. The role of envelope functions is considered, and we discuss the specific case of non-common atom interfaces. Experimental results and applications to interface characterization are presented. These calculations give a microscopic justification, and establish the limits of the heuristic 'H BF ' model. (author)

Virtual Distance and Soundstage, and their Impacts on Experienced Emotional Valence

DEFF Research Database (Denmark)

Christensen, Justin

2015-01-01

stimuli should cause stronger valenced responses in the nearfield than at a distance. Thus, music experienced as being negatively valenced at a distance should be more negatively valenced in nearfield, and music that is experienced as having a positive valence at a distance should be more positively......Research from animal ethology and affective neuroscience suggest that a listener’s perceived distance from a signal source can alter their experienced emotional valence of the music. Furthermore, appraisal theories of emotion suggest that emotionally valenced responses will diverge according...... to the type of emotion presented. For these exploratory investigations, subjects listen to selected musical excerpts on speakers in combination with a tactile transducer attached to their chair. The listening sessions are recorded on EEG supported by subject feedback responses. My hypothesis is that musical...

A study of the valence shell electronic states of s-triazine by photoabsorption spectroscopy and ab initio calculations

DEFF Research Database (Denmark)

Holland, D.M.P.; Shaw, D.A.; Stener, Mauro

2016-01-01

absorption bands due to excitation from the 1e00 or 6e0 orbitals. The interpretation of the experimental spectrum has been guided by transition energies and oscillator strengths, for Rydberg and valence states, calculated with the time-dependent version of density functional theory and with the coupled...... cluster linear response approach. The theoretical studies indicate that Rydberg/Rydberg and Rydberg/valence mixing is important....

Space-Valence Priming with Subliminal and Supraliminal Words

Directory of Open Access Journals (Sweden)

Ulrich eAnsorge

2013-02-01

Full Text Available To date it is unclear whether (1 awareness-independent non-evaluative semantic processes influence affective semantics and whether (2 awareness-independent affective semantics influence non-evaluative semantic processing. In the current study, we investigated these questions with the help of subliminal (masked primes and visible targets in a space-valence across-category congruence effect. In line with (1, we found that subliminal space prime words influenced valence classification of supraliminal target words (Experiment 1: Classifications were faster with a congruent prime (e.g., the prime ‘up’ before the target ‘happy’ than with an incongruent prime (e.g., the prime ‘up’ before the target ‘sad’. In contrast to (2, no influence of subliminal valence primes on the classification of supraliminal space targets into up- and down-words was found (Experiment 2. Control conditions showed that standard masked response-priming effects were found with both subliminal prime types, and that an across-category congruence effect was also found with supraliminal valence primes and spatial target words. The final Experiment 3 confirmed that the across-category congruence effect indeed reflected priming of target categorization of a relevant meaning category. Together, the data jointly confirmed prediction (1 that awareness-independent non-evaluative semantic priming influences valence judgments.

Valence, arousal and cognitive control: A voluntary task switching study

Directory of Open Access Journals (Sweden)

Jelle eDemanet

2011-11-01

Full Text Available The present study focused on the interplay between arousal, valence and cognitive control. To this end, we investigated how arousal and valence associated with affective stimuli influenced cognitive flexibility when switching between tasks voluntarily. Three hypotheses were tested. First, a valence hypothesis that states that the positive valence of affective stimuli will facilitate both global and task-switching performance because of increased cognitive flexibility. Second, an arousal hypothesis that states that arousal, and not valence, will specifically impair task-switching performance by strengthening the previously executed task-set. Third, an attention hypothesis that states that both cognitive and emotional control ask for limited attentional resources, and predicts that arousal will impair both global and task-switching performance. The results showed that arousal affected task-switching but not global performance, possibly by phasic modulations of the noradrenergic system that reinforces the previously executed task. In addition, positive valence only affected global performance but not task-switching performance, possibly by phasic modulations of dopamine that stimulates the general ability to perform in a multitasking environment.

Thermal recombination: Beyond the valence quark approximation

Energy Technology Data Exchange (ETDEWEB)

Mueller, B. [Department of Physics, Duke University, Durham, NC 27708 (United States); Fries, R.J. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)]. E-mail: fries@physics.umn.edu; Bass, S.A. [Department of Physics, Duke University, Durham, NC 27708 (United States); RIKEN BNL Research Center, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2005-07-07

Quark counting rules derived from recombination models agree well with data on hadron production at intermediate transverse momenta in relativistic heavy-ion collisions. They convey a simple picture of hadrons consisting only of valence quarks. We discuss the inclusion of higher Fock states that add sea quarks and gluons to the hadron structure. We show that, when recombination occurs from a thermal medium, hadron spectra remain unaffected by the inclusion of higher Fock states. However, the quark number scaling for elliptic flow is somewhat affected. We discuss the implications for our understanding of data from the Relativistic Heavy Ion Collider.

Negative pressure driven valence instability of Eu in cubic Eu0.4La0.6Pd3

International Nuclear Information System (INIS)

Pandey, Abhishek; Mazumdar, Chandan; Ranganathan, R

2009-01-01

We report the change in the valency of Eu-ions in the binary intermetallic cubic compound EuPd 3 induced by La doping at rare-earth sites. Doping of La generates negative chemical pressure in the lattice, resulting in a significant increase of the lattice parameter without altering the simple-cubic structure of the compound. Results of dc-magnetic measurements suggest that this increase in the lattice parameter is associated with the valence transition of Eu-ions from Eu 3+ to a mixed-valent state. As Eu 2+ -ions possess a large magnetic moment, this valence transition significantly modifies the magnetic behavior of the compound. In contrast to introducing boron at the vacant body center site of the unit cell to change the valency of Eu-ions, as in the case of EuPd 3 B, our results suggest it can also be altered by doping a rare-earth ion of larger size at the lattice site of Eu in EuPd 3 .

The acoustic correlates of valence depend on emotion family.

Science.gov (United States)

Belyk, Michel; Brown, Steven

2014-07-01

The voice expresses a wide range of emotions through modulations of acoustic parameters such as frequency and amplitude. Although the acoustics of individual emotions are well understood, attempts to describe the acoustic correlates of broad emotional categories such as valence have yielded mixed results. In the present study, we analyzed the acoustics of emotional valence for different families of emotion. We divided emotional vocalizations into "motivational," "moral," and "aesthetic" families as defined by the OCC (Ortony, Clore, and Collins) model of emotion. Subjects viewed emotional scenarios and were cued to vocalize congruent exclamations in response to them, for example, "Yay!" and "Damn!". Positive valence was weakly associated with high-pitched and loud vocalizations. However, valence interacted with emotion family for both pitch and amplitude. A general acoustic code for valence does not hold across families of emotion, whereas family-specific codes provide a more accurate description of vocal emotions. These findings are consolidated into a set of "rules of expression" relating vocal dimensions to emotion dimensions. Copyright © 2014 The Voice Foundation. Published by Mosby, Inc. All rights reserved.

Prediction of valence and arousal from music features

NARCIS (Netherlands)

Den Brinker, A.C.; Van Dinther, C.H.B.A.; Skowronek, J.

2011-01-01

Mood is an important attribute of music and knowledge on mood can beused as a basic ingredient in music recommender and retrieval systems. Moods are assumed to be dominantly determined by two dimensions:valence and arousal. An experiment was conducted to attain data forsong-based ratings of valence

Ueber das Mannheimer Woerterbuch zur Verbvalenz (About the Mannheim Dictionary of Verb Valence)

Science.gov (United States)

Schumacher, Helmut

1976-01-01

Describes the purpose, structure and application of this monolingual verb lexicon, which indicates the morphosyntactic environments of the most common German verbs. Mention is made of the forthcoming valence lexicon. The book is for teachers and textbook writers. (Text is in German.) (IFS/WGA)

Valence QCD: Connecting QCD to the quark model

International Nuclear Information System (INIS)

Liu, K.F.; Dong, S.J.; Draper, T.; Sloan, J.; Leinweber, D.; Woloshyn, R.M.

1999-01-01

A valence QCD theory is developed to study the valence quark properties of hadrons. To keep only the valence degrees of freedom, the pair creation through the Z graphs is deleted in the connected insertions, whereas the sea quarks are eliminated in the disconnected insertions. This is achieved with a new 'valence QCD' Lagrangian where the action in the time direction is modified so that the particle and antiparticle decouple. It is shown in this valence version of QCD that the ratios of isovector to isoscalar matrix elements (e.g., F A /D A and F S /D S ratios) in the nucleon reproduce the SU(6) quark model predictions in a lattice QCD calculation. We also consider how the hadron masses are affected on the lattice and discover new insights into the origin of dynamical mass generation. It is found that, within statistical errors, the nucleon and the Δ become degenerate for the quark masses we have studied (ranging from 1 to 4 times the strange mass). The π and ρ become nearly degenerate in this range. It is shown that valence QCD has the C, P, T symmetries. The lattice version is reflection positive. It also has the vector and axial symmetries. The latter leads to a modified partially conserved axial Ward identity. As a result, the theory has a U(2N F ) symmetry in the particle-antiparticle space. Through lattice simulation, it appears that this is dynamically broken down to U q (N F )xU bar q (N F ). Furthermore, the lattice simulation reveals spin degeneracy in the hadron masses and various matrix elements. This leads to an approximate U q (2N F )xU bar q (2N F ) symmetry which is the basis for the valence quark model. In addition, we find that the masses of N, Δ,ρ,π,a 1 , and a 0 all drop precipitously compared to their counterparts in the quenched QCD calculation. This is interpreted as due to the disappearance of the 'constituent' quark mass which is dynamically generated through tadpole diagrams. The origin of the hyperfine splitting in the baryon is

Processing negative valence of word pairs that include a positive word.

Science.gov (United States)

Itkes, Oksana; Mashal, Nira

2016-09-01

Previous research has suggested that cognitive performance is interrupted by negative relative to neutral or positive stimuli. We examined whether negative valence affects performance at the word or phrase level. Participants performed a semantic decision task on word pairs that included either a negative or a positive target word. In Experiment 1, the valence of the target word was congruent with the overall valence conveyed by the word pair (e.g., fat kid). As expected, response times were slower in the negative condition relative to the positive condition. Experiment 2 included target words that were incongruent with the overall valence of the word pair (e.g., fat salary). Response times were longer for word pairs whose overall valence was negative relative to positive, even though these word pairs included a positive word. Our findings support the Cognitive Primacy Hypothesis, according to which emotional valence is extracted after conceptual processing is complete.

Quantum computational capability of a 2D valence bond solid phase

International Nuclear Information System (INIS)

Miyake, Akimasa

2011-01-01

Highlights: → Our model is the 2D valence bond solid phase of a quantum antiferromagnet. → Universal quantum computation is processed by measurements of quantum correlations. → An intrinsic complexity of strongly-correlated quantum systems could be a resource. - Abstract: Quantum phases of naturally-occurring systems exhibit distinctive collective phenomena as manifestation of their many-body correlations, in contrast to our persistent technological challenge to engineer at will such strong correlations artificially. Here we show theoretically that quantum correlations exhibited in the 2D valence bond solid phase of a quantum antiferromagnet, modeled by Affleck, Kennedy, Lieb, and Tasaki (AKLT) as a precursor of spin liquids and topological orders, are sufficiently complex yet structured enough to simulate universal quantum computation when every single spin can be measured individually. This unveils that an intrinsic complexity of naturally-occurring 2D quantum systems-which has been a long-standing challenge for traditional computers-could be tamed as a computationally valuable resource, even if we are limited not to create newly entanglement during computation. Our constructive protocol leverages a novel way to herald the correlations suitable for deterministic quantum computation through a random sampling, and may be extensible to other ground states of various 2D valence bond phases beyond the AKLT state.

Effects of emotional valence and arousal on the voice perception network

Science.gov (United States)

Kotz, Sonja A.; Belin, Pascal

2017-01-01

Abstract Several theories conceptualise emotions along two main dimensions: valence (a continuum from negative to positive) and arousal (a continuum that varies from low to high). These dimensions are typically treated as independent in many neuroimaging experiments, yet recent behavioural findings suggest that they are actually interdependent. This result has impact on neuroimaging design, analysis and theoretical development. We were interested in determining the extent of this interdependence both behaviourally and neuroanatomically, as well as teasing apart any activation that is specific to each dimension. While we found extensive overlap in activation for each dimension in traditional emotion areas (bilateral insulae, orbitofrontal cortex, amygdalae), we also found activation specific to each dimension with characteristic relationships between modulations of these dimensions and BOLD signal change. Increases in arousal ratings were related to increased activations predominantly in voice-sensitive cortices after variance explained by valence had been removed. In contrast, emotions of extreme valence were related to increased activations in bilateral voice-sensitive cortices, hippocampi, anterior and midcingulum and medial orbito- and superior frontal regions after variance explained by arousal had been accounted for. Our results therefore do not support a complete segregation of brain structures underpinning the processing of affective dimensions. PMID:28449127

Future Research Directions in the Positive Valence Systems: Measurement, Development, and Implications for Youth Unipolar Depression.

Science.gov (United States)

Olino, Thomas M

2016-01-01

The Positive Valence Systems (PVS) have been introduced by the National Institute of Mental Health as a domain to help organize multiple constructs focusing on reward-seeking behaviors. However, the initial working model for this domain is strongly influenced by adult constructs and measures. Thus, the present review focuses on extending the PVS into a developmental context. Specifically, the review provides some hypotheses about the structure of the PVS, how PVS components may change throughout development, how family history of depression may influence PVS development, and potential means of intervening on PVS function to reduce onsets of depression. Future research needs in each of these areas are highlighted.

Electronic structure of ZrS{sub x}Se{sub 2-x} by density functional theory

Energy Technology Data Exchange (ETDEWEB)

Ghafari, Ailakbar; Moustafa, Mohamed; Janowitz, Christoph; Dwelk, Helmut; Manzke, Recardo [Institut fuer Physik, Humboldt-Universitaet zu Berlin, Newtonstr. 15, D-12489 Berlin (Germany); Bouchani, Arash [Physics Department, Islamic Azad University, Kermanshah Branch (Iran, Islamic Republic of)

2011-07-01

The electronic properties of the ZrS{sub x}Se{sub 2-x} (x varies between zero and two) semiconductors have been calculated by density functional theory (using the Wien2K code) employing the full potential Hamiltonian within the Generalized Gradient Approximation (GGA) method. The results obtained for the end members of the series, i.e. ZrS{sub 2} and ZrSe{sub 2} reveal that the valence band maximum and conduction band minimum are located at {gamma} and between {gamma} and K respectively which is in agreement with our photoemission experimental data. Trends in the electronic structure for the whole substitution series are discussed.

Calculation of the valence charge density and binding energy in a simple metal according to the neutral atom method: the Hartree-Fock ionic potential

International Nuclear Information System (INIS)

Dagens, L.

1975-01-01

The neutral atom method is generalized in order to deal with a Hartree-Fock nonlocal ionic potential. It is used to test the following metal potential, based upon a theoretical analysis due to Hedin and Lundquist. The true HF potential is used to describe the ionic part and a simple local density scheme (the Gaspar-Kohn-Sham approximation) is used for the valence part. The method is first applied to the calculation of the rigid neutral atom valence density of a few simple metals and the corresponding form factor n(q). The choice of the ionic potential (HF or GKS) is found to have a small but significant effect as far as n(q) is concerned. A comparison with experiment is made for Al and Be, using the available X-rays structure factor measurements. Good agreement is obtained for Al with the recent results of Raccah and Heinrich. No agreement is obtained with the Be results of Brown, although the general behavior of the observed and theoretical n(g) as function of g (reciprocal vector length) are found to be quite similar. The binding energy is calculated for Li, Be, Na, Mg and Al, using the Nozieres-Pines formula for the valence-valence correlation energy. The agreement with observed values is improved considerably when the present (HF+GKS) scheme is used, instead of the HFS completely local density scheme used in a previous work. The remaining discrepancies may be ascribed to the inaccuracy of the NP formula and to the neglect of the whole valence-core correlation energy [fr

Convergence of valence bands for high thermoelectric performance for p-type InN

International Nuclear Information System (INIS)

Li, Hai-Zhu; Li, Ruo-Ping; Liu, Jun-Hui; Huang, Ming-Ju

2015-01-01

Band engineering to converge the bands to achieve high valley degeneracy is one of effective approaches for designing ideal thermoelectric materials. Convergence of many valleys in the valence band may lead to a high Seebeck coefficient, and induce promising thermoelectric performance of p-type InN. In the current work, we have systematically investigated the electronic structure and thermoelectric performance of wurtzite InN by using the density functional theory combined with semiclassical Boltzmann transport theory. Form the results, it can be found that intrinsic InN has a large Seebeck coefficient (254 μV/K) and the largest value of Z e T is 0.77. The transport properties of p-type InN are better than that of n-type one at the optimum carrier concentration, which mainly due to the large Seebeck coefficient for p-type InN, although the electrical conductivity of n-type InN is larger than that of p-type one. We found that the larger Seebeck coefficient for p-type InN may originate from the large valley degeneracy in the valence band. Moreover, the low minimum lattice thermal conductivity for InN is one key factor to become a good thermoelectric material. Therefore, p-type InN could be a potential material for further applications in the thermoelectric area.

A numerical simulation model of valence-change-based resistive switching

OpenAIRE

Marchewka, Astrid

2017-01-01

Due to their superior scalability and performance, nanoscale resistive switches based on the valence-change mechanism are considered promising candidates for future nonvolatile memory and logic applications. These devices are metal-oxide-metal structures that can be reversibly switched between different resistance states by electrical signals. Typically, they contain one Schottky-like and one ohmic-like metal-oxide contact and exhibit bipolar switching. The switching mechanism and the initial...

Interpretation of monoclinic hafnia valence electron energy-loss spectra by time-dependent density functional theory

Science.gov (United States)

Hung, L.; Guedj, C.; Bernier, N.; Blaise, P.; Olevano, V.; Sottile, F.

2016-04-01

We present the valence electron energy-loss spectrum and the dielectric function of monoclinic hafnia (m -HfO2) obtained from time-dependent density-functional theory (TDDFT) predictions and compared to energy-filtered spectroscopic imaging measurements in a high-resolution transmission-electron microscope. Fermi's golden rule density-functional theory (DFT) calculations can capture the qualitative features of the energy-loss spectrum, but we find that TDDFT, which accounts for local-field effects, provides nearly quantitative agreement with experiment. Using the DFT density of states and TDDFT dielectric functions, we characterize the excitations that result in the m -HfO2 energy-loss spectrum. The sole plasmon occurs between 13 and 16 eV, although the peaks ˜28 and above 40 eV are also due to collective excitations. We furthermore elaborate on the first-principles techniques used, their accuracy, and remaining discrepancies among spectra. More specifically, we assess the influence of Hf semicore electrons (5 p and 4 f ) on the energy-loss spectrum, and find that the inclusion of transitions from the 4 f band damps the energy-loss intensity in the region above 13 eV. We study the impact of many-body effects in a DFT framework using the adiabatic local-density approximation (ALDA) exchange-correlation kernel, as well as from a many-body perspective using "scissors operators" matched to an ab initio G W calculation to account for self-energy corrections. These results demonstrate some cancellation of errors between self-energy and excitonic effects, even for excitations from the Hf 4 f shell. We also simulate the dispersion with increasing momentum transfer for plasmon and collective excitation peaks.

Valence photoelectron spectra of alkali bromides calculated within the propagator theory

DEFF Research Database (Denmark)

Karpenko, Alexander; Iablonskyi, Denys; Aksela, Helena

2013-01-01

The valence ionization spectra covering the binding energy range 0-45 eV of alkali bromide XBr (X = Li, Na, K, Rb) vapors are studied within the framework of the propagator theory. Relativistic Algebraic Diagrammatic Construction calculations have been carried out in order to investigate photoion...... photoionization processes and to describe molecular electronic structure. Theoretical results are compared with available experimental data....

Reducing the negative valence of stressful memories through emotionally valenced, modality-specific tasks

NARCIS (Netherlands)

Tadmor, Avia; McNally, Richard J; Engelhard, Iris M

2016-01-01

BACKGROUND AND OBJECTIVES: People who perform a cognitively demanding secondary task while recalling a distressing memory often experience the memory as less emotional, vivid, or accurate during subsequent recollections. In this experiment, we tested whether the emotional valence (positive versus

Valence, magnetism and conduction in the intermediate valence compounds: the case SmB6

International Nuclear Information System (INIS)

Derr, J.

2006-09-01

In some rare earth based compounds, the 4f level is situated so close to the Fermi level that the valence of the compound can become intermediate between two integer values. The so called 'intermediate valence' compound of Samarium hexaboride (SmB 6 ) is one typical example of the exciting physics which can result from this quantum equilibrium between two valence configurations. The first configuration (Sm 2+ ) corresponds to an insulating and non magnetic state whereas the second one (Sm 3+ ) would theoretically give a magnetic and metallic ground state. This dissertation deals with the influence of pressure on this equilibrium. Specific heat measurements under pressure evidenced a new long range magnetic ordering for pressures higher than p c ∼ 10 GPa. On another hand, transport measurements measured for the first time in good conditions of hydrostatics found a reliable and reproducible critical pressure for the insulator to metal transition equal to p c . The phase diagram of SmB 6 is now well known and the observation for the first time of a magnetic anomaly in the high pressure resistivity curves certifies that the onset of the magnetic phase really coincide with the closure of the gap. This change at the critical pressure p c is discussed in a general frame taking into account the Kondo lattice temperature as a key parameter for the renormalization of the wavefunction from one integer configuration to the other whereas the valence itself is still intermediate. This general idea seems to be valid also for other systems studied in this dissertation like SmS or TmSe and could even be valid for more general cases (Ytterbium, Cerium). In the same time, resistivity measurements under uniaxial stress were undertaken. The result is a strong anisotropy effect observed on the pressure dependence of the residual resistivity in the compound SmB 6 . The comparison with the transport under hydrostatic conditions enables us to consider a new idea for the nature of the gap

A precise determination of the nucleon structure functions in charged-current interactions on an iron target

International Nuclear Information System (INIS)

Vallage, B.

1987-01-01

570 000 neutrino-iron and 370 000 antineutrino-iron charged-current events were obtained from the Wide Band Beam exposure of the CDHS detector at CERN in 1983, at energies ranging from 20 to 400 GeV. These large statistics allowed a precise measurement of the charged-current differential cross-sections and a detailed study of systematic effects. The nucleon structure functions have been determined in the framework of the quark-parton model, in the kinematic range: 0.015 2 2 /c 2 . The longitudinal structure function F L (x) is in good agreement with the QCD predicted shape. Deviations from scale invariance are clearly seen from the functions F 2 and xF 3 . The Q 2 evolution of the valence quark distribution has been compared with the QCD prediction in order to measure the scale parameter Λ. A good agreement is obtained only if the low Q 2 points are removed from the comparison. Our experiment favours a value of Λ between 50 and 250 MeV [fr

Explaining the effect of event valence on unrealistic optimism.

Science.gov (United States)

Gold, Ron S; Brown, Mark G

2009-05-01

People typically exhibit 'unrealistic optimism' (UO): they believe they have a lower chance of experiencing negative events and a higher chance of experiencing positive events than does the average person. UO has been found to be greater for negative than positive events. This 'valence effect' has been explained in terms of motivational processes. An alternative explanation is provided by the 'numerosity model', which views the valence effect simply as a by-product of a tendency for likelihood estimates pertaining to the average member of a group to increase with the size of the group. Predictions made by the numerosity model were tested in two studies. In each, UO for a single event was assessed. In Study 1 (n = 115 students), valence was manipulated by framing the event either negatively or positively, and participants estimated their own likelihood and that of the average student at their university. In Study 2 (n = 139 students), valence was again manipulated and participants again estimated their own likelihood; additionally, group size was manipulated by having participants estimate the likelihood of the average student in a small, medium-sized, or large group. In each study, the valence effect was found, but was due to an effect on estimates of own likelihood, not the average person's likelihood. In Study 2, valence did not interact with group size. The findings contradict the numerosity model, but are in accord with the motivational explanation. Implications for health education are discussed.

Kekulé-based Valence Bond Model.I. The Ground-state Properties of Conjugated π-Systems

Institute of Scientific and Technical Information of China (English)

LI,Shu-Hua(黎书华); MA,Jing(马晶); JIANG,Yuan-Sheng(江元生)

2002-01-01

The Kekulé-based valence bond ( VB ) method, in which the VB model is solved using covalent Kekulé structures as basis functions, is justified in the present work. This method is dimonstrated to provide satisfactory descriptions for resoance energies and bond ang lengths of benzenoid hydrocarbons, being in good agreement with SCF-MO and experimental results. In additicn, an alternative way of discyssing characters of localizedsubstructures within a polyclic benzenoid system is suggested based upon such sunokufied VB calculations. Finally,the symmetries of VB ground states for nonalternant conjugated systems are also illustrated to be obtainable through these calculations, presenting very useful information for understanding the chemical behaviors of some nonalternant conjugated molecules.

Electronic structure of lanthanide scandates

Science.gov (United States)

Mizzi, Christopher A.; Koirala, Pratik; Marks, Laurence D.

2018-02-01

X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and density functional theory calculations were used to study the electronic structure of three lanthanide scandates: GdSc O3,TbSc O3 , and DySc O3 . X-ray photoelectron spectra simulated from first-principles calculations using a combination of on-site hybrid and GGA +U methods were found to be in good agreement with experimental x-ray photoelectron spectra. The hybrid method was used to model the ground state electronic structure and the GGA +U method accounted for the shift of valence state energies due to photoelectron emission via a Slater-Janak transition state approach. From these results, the lanthanide scandate valence bands were determined to be composed of Ln 4 f ,O 2 p , and Sc 3 d states, in agreement with previous work. However, contrary to previous work the minority Ln 4 f states were found to be located closer to, and in some cases at, the valence band maximum. This suggests that minority Ln 4 f electrons may play a larger role in lanthanide scandate properties than previously thought.

A study of the valence shell photoelectron and photoabsorption spectra of CF3SF5

International Nuclear Information System (INIS)

Holland, D M P; Shaw, D A; Walker, I C; McEwen, I J; Apra, E; Guest, M F

2005-01-01

The outer valence shell photoelectron spectrum of CF 3 SF 5 has been studied experimentally and theoretically. Synchrotron radiation has been used to record angle-resolved outer valence shell photoelectron spectra of CF 3 SF 5 in the photon energy range 18-60 eV. These spectra have allowed photoelectron asymmetry parameters and branching ratios to be derived. The Outer Valence Green's Function approach has been employed to calculate the molecular orbital configuration and associated binding energies. A charge distribution analysis has also been obtained. Assignments have been proposed for the peaks observed in the photoelectron spectrum. The absolute photoabsorption cross section of CF 3 SF 5 has been measured from threshold to 40 eV, and strongly resembles that of SF 6 . Assignments, involving intravalence transitions, have been proposed for some of the principal features appearing in the photoabsorption spectrum of CF 3 SF 5

Valence bond model potential energy surface for H4

International Nuclear Information System (INIS)

Silver, D.M.; Brown, N.J.

1980-01-01

Potential energy surfaces for the H 4 system are derived using the valence bond procedure. An ab initio evaluation of the valence bond energy expression is described and some of its numerical properties are given. Next, four semiempirical evaluations of the valence bond energy are defined and parametrized to yield reasonable agreement with various ab initio calculations of H 4 energies. Characteristics of these four H 4 surfaces are described by means of tabulated energy minima and equipotential contour maps for selected geometrical arrangements of the four nuclei

Time flies with music whatever its emotional valence.

Science.gov (United States)

Droit-Volet, Sylvie; Bigand, Emmanuel; Ramos, Danilo; Bueno, José Lino Oliveira

2010-10-01

The present study used a temporal bisection task to investigate whether music affects time estimation differently from a matched auditory neutral stimulus, and whether the emotional valence of the musical stimuli (i.e., sad vs. happy music) modulates this effect. The results showed that, compared to sine wave control music, music presented in a major (happy) or a minor (sad) key shifted the bisection function toward the right, thus increasing the bisection point value (point of subjective equality). This indicates that the duration of a melody is judged shorter than that of a non-melodic control stimulus, thus confirming that "time flies" when we listen to music. Nevertheless, sensitivity to time was similar for all the auditory stimuli. Furthermore, the temporal bisection functions did not differ as a function of musical mode. Copyright © 2010 Elsevier B.V. All rights reserved.

Developmental Reversals in False Memory: Effects of Emotional Valence and Arousal

Science.gov (United States)

Brainerd, C. J.; Holliday, R. E.; Reyna, V. F.; Yang, Y.; Toglia, M. P.

2010-01-01

Do the emotional valence and arousal of events distort children's memories? Do valence and arousal modulate counterintuitive age increases in false memory? We investigated those questions in children, adolescents, and adults using the Cornell/Cortland Emotion Lists, a word list pool that induces false memories and in which valence and arousal can…

Effect of laser irradiation on the structure and valence states of copper in Cu-phosphate glass by XPS studies

International Nuclear Information System (INIS)

Khattak, G.D.; Mekki, A.; Gondal, M.A.

2010-01-01

The effect of laser irradiation using three different wavelengths (IR, visible and UV) generated from Nd:YAG laser on the local glass structure as well as on the valence state of the copper ions in copper phosphate glass containing CuO with the nominal composition 0.30(CuO)-(0.70)(P 2 O 5 ), has been investigated by X-ray photoelectron spectroscopy (XPS). The presence of asymmetry and satellite peaks in the Cu 2p spectrum for the unirradiated sample is an indication of the presence of two different valence states, Cu 2+ and Cu + . Hence, the Cu 2p 3/2 spectrum was fitted to two Gaussian-Lorentzian peaks and the corresponding ratio, Cu 2+ /Cu total , determined from these relative areas clearly shows that copper ions exist predominately (>86%) in the Cu 2+ state for the unirradiated glass sample under investigation. For the irradiated samples the symmetry and the absence of satellite peaks in the Cu 2p spectra indicate the existence of the copper ions mostly in Cu + state. The O 1s spectra show slight asymmetry for the irradiated as well as unirradiated glass samples which result from two contributions, one from the presence of oxygen atoms in the P-O-P environment (bridging oxygen BO) and the other from oxygen in an P-O-Cu and P=O environment (non-bridging oxygen NBO). The ratio of NBO to total oxygen was found to increase with laser power.

Consistent gaussian basis sets of double- and triple-zeta valence with polarization quality of the fifth period for solid-state calculations.

Science.gov (United States)

Laun, Joachim; Vilela Oliveira, Daniel; Bredow, Thomas

2018-02-22

Consistent basis sets of double- and triple-zeta valence with polarization quality for the fifth period have been derived for periodic quantum-chemical solid-state calculations with the crystalline-orbital program CRYSTAL. They are an extension of the pob-TZVP basis sets, and are based on the full-relativistic effective core potentials (ECPs) of the Stuttgart/Cologne group and on the def2-SVP and def2-TZVP valence basis of the Ahlrichs group. We optimized orbital exponents and contraction coefficients to supply robust and stable self-consistent field (SCF) convergence for a wide range of different compounds. The computed crystal structures are compared to those obtained with standard basis sets available from the CRYSTAL basis set database. For the applied hybrid density functional PW1PW, the average deviations of calculated lattice constants from experimental references are smaller with pob-DZVP and pob-TZVP than with standard basis sets. © 2018 Wiley Periodicals, Inc. © 2018 Wiley Periodicals, Inc.

Valence change in rare earth semiconductors in many-impurity Anderson model

International Nuclear Information System (INIS)

Kocharyan, A.N.

1986-01-01

Green functions averaged over point impurity localization are found out in the simplest many-impurity model of rare earth semiconductor taking into account local Coulomb repulsion and hybridization of s- and f-electrons. Analytical expressions for s- and f-electron states density are obtained in the appoximation linear in can centration. Behaviour of a state density nearly the continuous spectrum edge and in the vicinity of the f-level is studied as a function of electron parameters. A comparison with the Anderson one-impurity model is performed. It is shown that essential energy spectrum conversion occurs in the case of a great number of impurities close to the continuous spectrum. Continuous spectrum boundaries are found out, and conditions are defined, at which the forbidden energy gap occurs in the continuous spectrum nearly a f-level. Effect of the coherent conversion of spectrum on behaviour of valence in changing f-level position is analyzed. It is shown that in the lack of electron-lattice interaction the phase transition with valence change occurs in a smooth manner as in the model with strictly periodic Andersen lattice

The effects of valence-based and discrete emotional states on aesthetic response.

Science.gov (United States)

Cheng, Yin-Hui

2013-01-01

There is increasing recognition that consumer aesthetics--the responses of consumers to the aesthetic or appearance aspects of products--has become an important area of marketing in recent years. Consumer aesthetic responses to a product are a source of pleasure for the consumer. Previous research into the aesthetic responses to products has often emphasized exterior factors and visual design, but studies have seldom considered the psychological aesthetic experience of consumers, and in particular their emotional state. This study attempts to bridge this gap by examining the link between consumers' emotions and their aesthetic response to a product. Thus, the major goal of this study was to determine how valence-based and discrete emotional states influence choice. In Studies 1 and 2, positive and negative emotions were manipulated to implement two different induction techniques and explore the effect of emotions on participants' choices in two separate experiments. The results of both experiments confirmed the predictions, indicating that aesthetic responses and purchase intention are functions of emotional valence, such that both are stronger for people in a positive emotional state than for those in a negative emotional state. Study 2 also used a neutral affective state to establish the robustness of this observed effect of incidental affect. The results of Study 3 demonstrate that aesthetic response and purchase intention are not only a function of affect valence, but also are affected by the certainty appraisal associated with specific affective states. This research, therefore, contributes to the literature by offering empirical evidence that incidental affect is a determinant of aesthetic response.

Visible light photoreactivity from hybridization states between carbon nitride bandgap states and valence states in Nb and Ti oxides

Energy Technology Data Exchange (ETDEWEB)

Lee, Hosik, E-mail: hosiklee@gmail.com [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology (UNIST), Unist-gil 100 Eonyang-eup, Ulsan 689-798 (Korea, Republic of); Ohno, Takahisa, E-mail: OHNO.Takahisa@nims.go.jp [Global Research Center for Environment and Energy based on Nanomaterials Science (GREEN), National Institute for Material Science, 1-2-1 Sengen, Tsukuba (Japan); Computational Materials Science Unit (CMSU), National Institute for Materials Science (NIMS), Tsukuba, Ibaraki 305-0047 (Japan)

2013-03-29

Highlights: ► Origin of bandgap reduction for visible photoreactivity is suggested. ► Carbon nitride adsorption in interlayer space can induce the bandgap reduction. ► The electronic structures are studied by density functional theory calculations. - Abstract: For better efficiency as photocatalysts, N-doping for visible light reactivity has been intensively studied in Lamellar niobic and titanic solid acids (HNb{sub 3}O{sub 8}, H{sub 2}Ti{sub 4}O{sub 9}), and its microscopic structures have been debated in this decade. We calculate the layered solid acids’ structures and bandgaps. Bandgap reduction by carbon nitride adsorption in interlayer space is observed computationally. It originates from localized nitrogen states which form delocalized top-valence states by hybridizing with the host oxygen states and can contribute to photo-current.

Pressure-induced valence change and moderate heavy fermion state in Eu-compounds

Science.gov (United States)

Honda, Fuminori; Okauchi, Keigo; Sato, Yoshiki; Nakamura, Ai; Akamine, Hiromu; Ashitomi, Yosuke; Hedo, Masato; Nakama, Takao; Takeuchi, Tetsuya; Valenta, Jaroslav; Prchal, Jiri; Sechovský, Vladimir; Aoki, Dai; Ōnuki, Yoshichika

2018-05-01

A pressure-induced valence transition has attracted much attention in Eu-compounds. Among them, EuRh2Si2, EuNi2Ge2, and EuCo2Ge2 reveal the valence transition around 1, 2, and 3 GPa, respectively. We have succeeded in growing single crystals of EuT2X2 (T: transition metal, X: Si, Ge) and studied electronic properties under pressure. EuRh2Si2 indicates a first-order valence transition between 1 and 2 GPa, with a large and prominent hysteresis in the electrical resistivity. At higher pressures, the first-order valence transition changes to a cross-over regime with an intermediate valence state. Tuning of the valence state with pressure is reflected in a drastic change of the temperature dependence of the electrical resistivity in EuRh2Si2 single crystals. Effect of pressure on the valence states on EuRh2Si2, EuIr2Si2, EuNi2Ge2, and EuCo2Ge2, as well as an isostructural related compound EuGa4, are reviewed.

CzEngVallex: a Bilingual Czech-English Valency Lexicon

Directory of Open Access Journals (Sweden)

Urešová Zdeňka

2016-04-01

Full Text Available This paper introduces a new bilingual Czech-English verbal valency lexicon (called CzEng-Vallex representing a relatively large empirical database. It includes 20,835 aligned valency frame pairs (i.e., verb senses which are translations of each other and their aligned arguments. This new lexicon uses data from the Prague Czech-English Dependency Treebank and also takes advantage of the existing valency lexicons for both languages: the PDT-Vallex for Czech and the EngVallex for English. The CzEngVallex is available for browsing as well as for download in the LINDAT/CLARIN repository.

THE VALENCE OF CORPUSCULAR PROTEINS.

Science.gov (United States)

Gorin, M H; Mover, L S

1942-07-20

BY THE USE OF TWO EXTREME MODELS: a hydrated sphere and an unhydrated rod the valence (net charge) of corpuscular proteins can be successfully calculated from electric mobility data by the Debye-Hückel theory (modified to include the effect of the ions in the ion atmosphere) in conjunction with the electrophoretic theory of Henry. As pointed out by Abramson, this permits a comparison with values for the valence from titration data. Electrometric titration measurements of serum albumin B (Kekwick) have been determined at several ionic strengths. These results, together with the available data in the literature for serum albumin B, egg albumin, and beta-lactoglobulin have been used to compare values for the valence calculated from measurements of titration, electrophoresis, and membrane potentials. The results indicate that the usual interpretation of titration curves is open to serious question. By extrapolation of the titration data to zero ionic strength and protein concentration, there results an "intrinsic" net charge curve describing the binding of H(+) (OH(-)) ion alone. This curve agrees closely, in each case, with values of the valence calculated from mobility data (which in turn are in close accord with those estimated from membrane potential measurements). The experimental titration curves in the presence of appreciable quantities of ions and protein deviate widely from the ideal curve. It is suggested that, under these conditions, binding of undissociated acid (base) leads to erroneous values for the net charge. This binding would not affect the electrophoretic mobility. Values of the net charge obtained by the two extreme models from electrophoretic data are in agreement within 15 to 20 per cent. The agreement between the cylindrical model and the titration data is somewhat better in each case than with the sphere; i.e., this comparison enables a choice to be made between asymmetry and hydration in the interpretation of results from sedimentation and

[Connection between the evaluation of positive or negative valence and verbal responses to a lexical decision making task].

Science.gov (United States)

Brouillet, Thibaut; Syssau, Arielle

2005-12-01

Evaluation of the positive or negative valence of a stimulus is an activity that is part of any emotional experience that has been mostly studied using the affective priming paradigm. When the prime and the target have the same valence (e.g. positive prime and positive target), the target response is facilitated as a function of opposing valence conditions (e.g. negative prime and positive target). These studies show that this evaluation is automatic but depends on the nature of the task's implied response because the priming effects are only observed for positive responses, not for negative responses. This result was explained in automatic judgmental tendency model put forth by Abelson and Rosenberg (1958) and Klauer and Stern (1992). In this model, affective priming assumes there is an overlap between both responses, the first response taking precedence as a function of the prime-target valence, and the second response one that is required by the task. We are assuming that another type of response was not foreseen under this model. In fact, upon activating the valence for each of the prime-target elements, two preliminary responses would be activated before the response on the prime-target valence relationship. These responses are directly linked to the prime and target evaluation independently of the prime-target relationship. This hypothesis can be linked to the larger hypothesis whereby the evaluative process is related to two distinct motivational systems corresponding to approach and avoidance behaviour responses (Lang, Bradley, & Cuthbert, 1990; Neuman & Strack, 2000; Cacciopo, Piester & Bernston, 1993). In this study, we use the hypothesis that when a word leads to a positive valence evaluation, this favours a positive verbal response and inversely, a negative valence word favours a negative response. We are testing this hypothesis outside the affective priming paradigm to study to what extent evaluating a word, even when it is not primed, activates both

Photoelectron spectra and electronic structure of some spiroborate complexes

Energy Technology Data Exchange (ETDEWEB)

Vovna, V.I.; Tikhonov, S.A.; Lvov, I.B., E-mail: lvov.ib@dvfu.ru; Osmushko, I.S.; Svistunova, I.V.; Shcheka, O.L.

2014-12-15

Highlights: • The electronic structure of three spiroborate complexes—boron 1,2-dioxyphenylene β-diketonates has been investigated. • UV and X-ray photoelectron spectra have been interpreted. • DFT calculations have been used for interpretation of spectral bands. • The binding energy of nonequivalent carbon and oxygen atoms were measured. • The structure of X-ray photoelectron spectra of the valence electrons is in good agreement with the energies and composition of Kohn–Sham orbitals. - Abstract: The electronic structure of the valence and core levels of three spiroborate complexes – boron 1,2-dioxyphenylene β-diketonates – has been investigated by methods of UV and X-ray photoelectron spectroscopy and quantum chemical density functional theory. The ionization energy of π- and n-orbitals of the dioxyphenylene fragment and β-diketonate ligand were measured from UV photoelectron spectra. This made it possible to determine the effect of substitution of one or two methyl groups by the phenyl in diketone on the electronic structure of complexes. The binding energy of nonequivalent carbon and oxygen atoms were measured from X-ray photoelectron spectra. The results of calculations of the energy of the valence orbitals of complexes allowed us to refer bands observed in the spectra of the valence electrons to the 2s-type levels of carbon and oxygen.

Composition-induced structural, electrical, and magnetic phase transitions in AX-type mixed-valence cobalt oxynitride epitaxial thin films

Energy Technology Data Exchange (ETDEWEB)

Takahashi, Jumpei; Oka, Daichi [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu, Kawasaki 213-0012 (Japan); Hirose, Yasushi, E-mail: hirose@chem.s.u-tokyo.ac.jp; Yang, Chang; Fukumura, Tomoteru; Hasegawa, Tetsuya [Department of Chemistry, School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu, Kawasaki 213-0012 (Japan); CREST, Japan Science and Technology Agency, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Nakao, Shoichiro [Kanagawa Academy of Science and Technology (KAST), 3-2-1 Sakado, Takatsu, Kawasaki 213-0012 (Japan); CREST, Japan Science and Technology Agency, 7-3-1 Hongo, Bunkyo, Tokyo 113-0033 (Japan); Harayama, Isao; Sekiba, Daiichiro [University of Tsukuba Tandem Accelerator Complex (UTTAC), 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8577 (Japan)

2015-12-07

Synthesis of mid- to late-transition metal oxynitrides is generally difficult by conventional thermal ammonolysis because of thermal instability. In this letter, we synthesized epitaxial thin films of AX-type phase-pure cobalt oxynitrides (CoO{sub x}N{sub y}) by using nitrogen-plasma-assisted pulsed laser deposition and investigated their structural, electrical, and magnetic properties. The CoO{sub x}N{sub y} thin films with 0 ≤ y/(x + y) ≤ 0.63 grown on MgO (100) substrates showed a structural phase transition from rock salt (RS) to zinc blend at the nitrogen content y/(x + y) ∼ 0.5. As the nitrogen content increased, the room-temperature electrical resistivity of the CoO{sub x}N{sub y} thin films monotonically decreased from the order of 10{sup 5} Ω cm to 10{sup −4} Ω cm. Furthermore, we observed an insulator-to-metal transition at y/(x + y) ∼ 0.34 in the RS-CoO{sub x}N{sub y} phase, which has not yet been reported in Co{sup 2+}/Co{sup 3+} mixed-valence cobalt oxides with octahedral coordination. The low resistivity in the RS-CoO{sub x}N{sub y} phase, on the 10{sup −3} Ω cm order, may have originated from the intermediate spin state of Co{sup 3+} stabilized by the lowered crystal field symmetry of the CoO{sub 6−n}N{sub n} octahedra (n = 1, 2,…5). Magnetization measurements suggested that a magnetic phase transition occurred in the RS-CoO{sub x}N{sub y} films during the insulator-to-metal transition. These results demonstrate that low-temperature epitaxial growth is a promising approach for exploring novel electronic functionalities in oxynitrides.

Composition-induced structural, electrical, and magnetic phase transitions in AX-type mixed-valence cobalt oxynitride epitaxial thin films

International Nuclear Information System (INIS)

Takahashi, Jumpei; Oka, Daichi; Hirose, Yasushi; Yang, Chang; Fukumura, Tomoteru; Hasegawa, Tetsuya; Nakao, Shoichiro; Harayama, Isao; Sekiba, Daiichiro

2015-01-01

Synthesis of mid- to late-transition metal oxynitrides is generally difficult by conventional thermal ammonolysis because of thermal instability. In this letter, we synthesized epitaxial thin films of AX-type phase-pure cobalt oxynitrides (CoO x N y ) by using nitrogen-plasma-assisted pulsed laser deposition and investigated their structural, electrical, and magnetic properties. The CoO x N y thin films with 0 ≤ y/(x + y) ≤ 0.63 grown on MgO (100) substrates showed a structural phase transition from rock salt (RS) to zinc blend at the nitrogen content y/(x + y) ∼ 0.5. As the nitrogen content increased, the room-temperature electrical resistivity of the CoO x N y thin films monotonically decreased from the order of 10 5  Ω cm to 10 −4  Ω cm. Furthermore, we observed an insulator-to-metal transition at y/(x + y) ∼ 0.34 in the RS-CoO x N y phase, which has not yet been reported in Co 2+ /Co 3+ mixed-valence cobalt oxides with octahedral coordination. The low resistivity in the RS-CoO x N y phase, on the 10 −3  Ω cm order, may have originated from the intermediate spin state of Co 3+ stabilized by the lowered crystal field symmetry of the CoO 6−n N n octahedra (n = 1, 2,…5). Magnetization measurements suggested that a magnetic phase transition occurred in the RS-CoO x N y films during the insulator-to-metal transition. These results demonstrate that low-temperature epitaxial growth is a promising approach for exploring novel electronic functionalities in oxynitrides

Valence fluctuations between two magnetic configurations

International Nuclear Information System (INIS)

Mazzaferro, J.O.

1982-01-01

The subject of this work is the study of a microscopic model which describes TmSe through its most important feature, i.e.: the valence fluctuations between two magnetic configurations. Chapter I is a general review of the most important physical properties of rare-earth systems with intermediate valence (I.V.) and a general description of experimental results and theoretical models on Tm compounds. In Chapter II the Hamiltonian model is discussed and the loss of rotational invariance is also analyzed. Chapter III is devoted to the study of non-stoichiometric Tsub(x)Se compounds. It is shown that these compounds can be considered as a mixture of TmSe (I.V. system) and Tm 3+ 0.87Se. Chapter IV is devoted to the calculation of spin-and charge susceptibilities. The results obtained permit to explain the essential features of the neutron scattering spectrum in TmSe. In Chapter V, an exactly solvable periodic Hamiltonian is presented. From the experimental results, some fundamental features are deduced to describe TmSe as an intermediate valence system whose two accessible ionic configurations are magnetic (degenerated fundamental state). (M.E.L) [es

5th International Conference on Valence Fluctuations

CERN Document Server

Malik, S

1987-01-01

During the Koln meeting (August 28-31, 1984), Irdia was chosen as the venue for the next International Conference on Valence Fluctuations. lhis was in recognition ard appreciation of the work done, both experimental ard theoretical, by the Irdian scientists in this area during the last decade. We decided to hold this Conference in the month of January, 1987 at Bangalore. lhe subject of Valence Fluctuations has kept itself alive ard active as it has provided many shocks ard suprises particularly among the Ce- ard U-based intermetallies. lhe richness of many interesting physical phenomena occurring in mixed valent materials, the flexibility of modifying their physical properties (by alloying, for example) ard the possibility of synthesizing a wide variety of new such materials seem to be the key factors in this regard. Barely six months before this Conference, an International Conference on Anomalous Rare Earths and Actinides (ICAREA) had been held at Grenoble (July, 1986) which also focussed on mixed valence a...

Chemical states and electronic structure of a HfO(-2)/Ge(001) interface

International Nuclear Information System (INIS)

Seo, Kang-ill; McIntyre, Paul C.; Stanford U., Materials Sci. Dept.; Sun, Shiyu; Lee, Dong-Ick; Pianetta, Piero; SLAC, SSRL; Saraswat, Krishna C.; Stanford U., Elect. Eng. Dept.

2005-01-01

We report the chemical bonding structure and valence band alignment at the HfO 2 /Ge (001) interface by systematically probing various core level spectra as well as valence band spectra using soft x-rays at the Stanford Synchrotron Radiation Laboratory. We investigated the chemical bonding changes as a function of depth through the dielectric stack by taking a series of synchrotron photoemission spectra as we etched through the HfO 2 film using a dilute HF-solution. We found that a very non-stoichiometric GeO x layer exists at the HfO 2 /Ge interface. The valence band spectra near the Fermi level in each different film structure were carefully analyzed, and as a result, the valence band offset between Ge and GeO x was determined to be ΔE v (Ge-GeO x ) = 2.2 ± 0.15 eV, and that between Ge and HfO 2 , ΔE v (Ge-HfO 2 ) = 2.7 ± 0.15 eV

Mixed meson masses with domain-wall valence and staggered sea fermions

International Nuclear Information System (INIS)

Orginos, Kostas; Walker-Loud, Andre

2008-01-01

Mixed action lattice calculations allow for an additive lattice-spacing-dependent mass renormalization of mesons composed of one sea and one valence quark, regardless of the type of fermion discretization methods used in the valence and sea sectors. The value of the mass renormalization depends upon the lattice actions used. This mixed meson mass shift is an important lattice artifact to determine for mixed action calculations; because it modifies the pion mass, it plays a central role in the low-energy dynamics of all hadronic correlation functions. We determine the leading order, O(a 2 ), and next-to-leading order, O(a 2 m π 2 ), additive mass shift of valence-sea mesons for a mixed lattice action with domain-wall valence fermions and rooted staggered sea fermions, relevant to the majority of current large scale mixed action lattice efforts. We find that, on the asqtad-improved coarse MILC lattices, this additive mass shift is well parametrized in lattice units by Δ(am) 2 =0.034(2)-0.06(2)(am π ) 2 , which in physical units, using a=0.125 fm, corresponds to Δ(m) 2 =(291±8 MeV) 2 -0.06(2)m π 2 . In terms of the mixed action effective field theory parameters, the corresponding mass shift is given by a 2 Δ Mix =(316±4 MeV) 2 at leading order plus next-to-leading order corrections including the necessary chiral logarithms for this mixed action calculation, determined in this work. Within the precision of our calculation, one cannot distinguish between the full next-to-leading order effective field theory analysis of this additive mixed meson mass shift and the parametrization given above.

Effects of Electric Field on the Valence-Bond Property of an Electron in a Quantum-Dot Molecule

Institute of Scientific and Technical Information of China (English)

王立民; 罗莹; 马本堃

2002-01-01

The electronic structure of the quantum-dot molecules in an electric field is investigated by the finite element method with the effective mass approximation. The numerical calculation results show that the valence bond of the quantum-dot molecule alternates between covalent bonds and ionic bonds as the electric field increases. The valence-bond property can be reflected by the oscillator strength of the intraband transition. The bound state with the highest energy level in the quantum-dot molecule gradually changes into a quasibound state when the electric field increases.

Memory transfer for emotionally valenced words between identities in dissociative identity disorder.

Science.gov (United States)

Huntjens, Rafaële J C; Peters, Madelon L; Woertman, Liesbeth; van der Hart, Onno; Postma, Albert

2007-04-01

The present study aimed to determine interidentity retrieval of emotionally valenced words in dissociative identity disorder (DID). Twenty-two DID patients participated together with 25 normal controls and 25 controls instructed to simulate DID. Two wordlists A and B were constructed including neutral, positive and negative material. List A was shown to one identity, while list B was shown to another identity claiming total amnesia for the words learned by the first identity. The identity claiming amnesia was tested for intrusions from list A words into the recall of words from list B and recognition of the words learned by both identities. Test results indicated no evidence of total interidentity amnesia for emotionally valenced material in DID. It is argued that dissociative amnesia in DID may more adequately be described as a disturbance in meta-memory functioning instead of an actual retrieval inability.

Work Valence as a Predictor of Academic Achievement in the Family Context

Science.gov (United States)

Porfeli, Erik; Ferrari, Lea; Nota, Laura

2013-01-01

This study asserts a theoretical model of academic and work socialization within the family setting. The presumed associations between parents' work valences, children's work valences and valence perceptions, and children's academic interest and achievement are tested. The results suggest that children's perceptions of parents mediate the…

Processing Metaphors in the Elderly: Does Valence Matter?

Directory of Open Access Journals (Sweden)

Bartczak Marlena

2017-12-01

Full Text Available Much evidence from theory and research points towards difficulties in processing metaphors by elderly people. These difficulties are usually associated with working memory and inhibitory control deficits observed in this age group, as these very functions play a crucial part in efficient metaphor processing. However, results of research on understanding metaphorical content by elderly people are inconclusive. The following article reviews studies showing that metaphor processing relies on a set of complex variables, which might explain the inconclusiveness of previous results. Though we acknowledge the role of interindividual factors (differences in cognitive functioning among the elderly, we focus on the properties of the metaphor stimuli themselves, especially those of conventionalization and valence, as they might influence the processing of verbal metaphors by people in older age groups.

Experimental Constraints on the Partitioning and Valence of V and Cr in Garnet and Coexisting Glass

Science.gov (United States)

Righter, K.; Sutton, S.; Berthet, S.; Newville, M.

2008-01-01

A series of experiments with garnet and coexisting melt have been carried out across a range of oxygen fugacities (near hematite-magnetite (HM) to below the iron-wustite (IW) buffers) at 1.7 GPa to study the partitioning and valence of Cr and V in both phases. Experiments were carried out in a non end loaded piston cylinder apparatus, and the run products were analyzed with electron microprobe and xray absorption near edge structure (XANES) analysis at beamline 13-ID at the Advanced Photon Source of Argonne National Lab. The valence of vanadium and chromium were determined using the position and intensity of the Ka pre-edge peaks, calibrated on a series of Cr and Vbearing standard glasses. This technique has been applied to V and Cr in glasses and V in spinels previously, and in these isotropic phases there are no orientational effects on the XANES spectra (Righter et al., 2006, Amer. Mineral. 91, 1643-1656). We also now demonstrate this to be true for V and Cr in garnet. Also, previous work has shown that V has a higher valence in the glass (or melt) than in the coexisting spinel. This is also true for V in garnet-glass pairs in this study. Vanadium valence in garnets varies from 2.7 below the IW buffer to 3.7 near HM, and for coexisting glass it varies from 3.2 to 4.3. Vanadium valence measured in some natural garnets from mantle localities indicates V in the more reduced range at 2.5. Comparisons will be made between fO2 estimated from V valence and other methods for garnet-bearing mantle samples. In contrast, Cr valence measured in garnet and coexisting glass for all experimental and natural samples is 2.9- 3.0, suggesting that the valence of Cr does not vary within either phase across a large fO2 range. These results demonstrate that while V varies from 2+ to 3+ to 4+ in garnet-melt systems, Cr does not, and this will ultimately affect the partitioning behavior of these two elements in natural systems. Garnet/melt D(Cr) are between 12 and 17 across this range

Emotions and false memories: valence or arousal?

Science.gov (United States)

Corson, Yves; Verrier, Nadège

2007-03-01

The effects of mood on false memories have not been studied systematically until recently. Some results seem to indicate that negative mood may reduce false recall and thus suggest an influence of emotional valence on false memory. The present research tested the effects of both valence and arousal on recall and recognition and indicates that the effect is actually due to arousal. In fact, whether participants' mood is positive, negative, or neutral, false memories are significantly more frequent under conditions of high arousal than under conditions of low arousal.

Valency state changes in lanthanide-contained systems under high pressure

Energy Technology Data Exchange (ETDEWEB)

Jayaraman, A

1980-08-01

Changes in valency state induced by pressure in samarium sulphide SmS remind one of alchemy, as the mat black initial substance shines golden after the electron transition. The alchemist's dream is of course not realized, however the compound does exhibit an unusually interesting behaviour in the new state. The valency state of samarium as newly appeared fluctuated very rapidly between two electron configurations. Manipulation of the valency state by pressure or chemical substitution can basically change the physical properties of systems containing lanthanides. The phenomena are described and discussed in the following survey.

Valence electron structure and properties of stabilized ZrO2

Institute of Scientific and Technical Information of China (English)

2008-01-01

To reveal the properties of stabilizers in ZrO2 on nanoscopic levels, the valence electron structures of four stable ZrO2 phases and c-ZrO2 were analyzed on the basis of the empirical electron theory of solids and molecules. The results showed that the hybridization levels of Zr atoms in c-ZrO2 doped with Ca and Mg dropped from B17 to B13, the hybridization levels of Zr atoms in c-ZrO2 doped with Y and Ce dropped from B17 to B15, and that the four stabilizing atoms all made the hybridization levels of O atoms drop from level 4 to level 2. The numbers of covalent electrons in the strongest covalent bond in the descending order are c-ZrO2>Zr0.82Ce0.18O2> Zr0.82Y0.18O1.91>Zr0.82Mg0.18O1.82>Zr0.82Ca0.18O1.82. The bond energies of the strongest covalent bond and the melting points of the solid solutions in the descending order are Zr0.82Ce0.18O2> c-ZrO2>Zr0.82Y0.18O1.91>Zr0.82Mg0.18O1.82>Zr0.82Ca0.18O1.82. The percent-ages of the total number of covalent electrons in the descending order are c-ZrO2>Zr0.82Y0.18O1.91> Zr0.82Ce0.18O2>Zr0.82Mg0.18O1.82> Zr0.82Ca0.18O1.82. From the above analysis, it can be concluded that the stabilizing degrees of the four stabilizers in the descending order are CaO> MgO>Y2O3>CeO2.

Non-verbal emotion communication training induces specific changes in brain function and structure.

Science.gov (United States)

Kreifelts, Benjamin; Jacob, Heike; Brück, Carolin; Erb, Michael; Ethofer, Thomas; Wildgruber, Dirk

2013-01-01

The perception of emotional cues from voice and face is essential for social interaction. However, this process is altered in various psychiatric conditions along with impaired social functioning. Emotion communication trainings have been demonstrated to improve social interaction in healthy individuals and to reduce emotional communication deficits in psychiatric patients. Here, we investigated the impact of a non-verbal emotion communication training (NECT) on cerebral activation and brain structure in a controlled and combined functional magnetic resonance imaging (fMRI) and voxel-based morphometry study. NECT-specific reductions in brain activity occurred in a distributed set of brain regions including face and voice processing regions as well as emotion processing- and motor-related regions presumably reflecting training-induced familiarization with the evaluation of face/voice stimuli. Training-induced changes in non-verbal emotion sensitivity at the behavioral level and the respective cerebral activation patterns were correlated in the face-selective cortical areas in the posterior superior temporal sulcus and fusiform gyrus for valence ratings and in the temporal pole, lateral prefrontal cortex and midbrain/thalamus for the response times. A NECT-induced increase in gray matter (GM) volume was observed in the fusiform face area. Thus, NECT induces both functional and structural plasticity in the face processing system as well as functional plasticity in the emotion perception and evaluation system. We propose that functional alterations are presumably related to changes in sensory tuning in the decoding of emotional expressions. Taken together, these findings highlight that the present experimental design may serve as a valuable tool to investigate the altered behavioral and neuronal processing of emotional cues in psychiatric disorders as well as the impact of therapeutic interventions on brain function and structure.

Topologically distinct classes of valence-bond solid states with their parent Hamiltonians

International Nuclear Information System (INIS)

Tu Honghao; Zhang Guangming; Xiang Tao; Liu Zhengxin; Ng Taikai

2009-01-01

We present a general method to construct one-dimensional translationally invariant valence-bond solid states with a built-in Lie group G and derive their matrix product representations. The general strategies to find their parent Hamiltonians are provided so that the valence-bond solid states are their unique ground states. For quantum integer-spin-S chains, we discuss two topologically distinct classes of valence-bond solid states: one consists of two virtual SU(2) spin-J variables in each site and another is formed by using two SO(2S+1) spinors. Among them, a spin-1 fermionic valence-bond solid state, its parent Hamiltonian, and its properties are discussed in detail. Moreover, two types of valence-bond solid states with SO(5) symmetries are further generalized and their respective properties are analyzed as well.

Local valence balance in the structure of a high-temperature superconductor

International Nuclear Information System (INIS)

Nalbandyan, V.B.

1990-01-01

Hitherto superconductivity of complex oxides has been observed only if the metal is present in a mixed (nonintegral) degree of oxidation. It is of interest to verify the statement that in YBa 2 Cu 3 O x there is no copper in a degree of oxidation above 2+; instead of this, part of the oxygen is in the degree of oxidation 1-. Thus, the calculations of the valence forces tell against the presence of copper in a mixed degree of oxidation between 2+ and 3+ in high-temperature superconductors of the stoichiometric composition RBa 2 Cu 3 O 7 . In two-dimensional layers, copper is in the degree of oxidation 2+ (or even lower), while the electron holes are concentrated in one-dimensional chains - either in the form Cu(3+) or in the form O(1-)

Valence Band Structure of InAs1-xBix and InSb1-xBix Alloy Semiconductors Calculated Using Valence Band Anticrossing Model

Directory of Open Access Journals (Sweden)

D. P. Samajdar

2014-01-01

Full Text Available The valence band anticrossing model has been used to calculate the heavy/light hole and spin-orbit split-off energies in InAs1-xBix and InSb1-xBix alloy systems. It is found that both the heavy/light hole, and spin-orbit split E+ levels move upwards in energy with an increase in Bi content in the alloy, whereas the split E− energy for the holes shows a reverse trend. The model is also used to calculate the reduction of band gap energy with an increase in Bi mole fraction. The calculated values of band gap variation agree well with the available experimental data.

Developmental Reversals in False Memory: Effects of Emotional Valence and Arousal

OpenAIRE

Brainerd, C. J.; Holliday, R. E.; Reyna, V. F.; Yang, Y.; Toglia, M. P.

2010-01-01

Do the emotional valence and arousal of events distort children’s memories? Do valence and arousal modulate counterintuitive age increases in false memory? We investigated those questions in children, adolescents, and adults using the Cornell/Cortland Emotion Lists, a word list pool that induces false memories and in which valence and arousal can be manipulated factorially. False memories increased with age for unpresented semantic associates of word lists, and net accuracy (the ratio of true...

Hard x-ray photoemission study of the temperature-induced valence transition system EuNi2(Si1-xGex) 2

Science.gov (United States)

Ichiki, Katsuya; Mimura, Kojiro; Anzai, Hiroaki; Uozumi, Takayuki; Sato, Hitoshi; Utsumi, Yuki; Ueda, Shigenori; Mitsuda, Akihiro; Wada, Hirofumi; Taguchi, Yukihiro; Shimada, Kenya; Namatame, Hirofumi; Taniguchi, Masaki

2017-07-01

We investigated the bulk-derived electronic structure of the temperature-induced valence transition system EuNi2(Si1 -xGex )2 (x =0.70 , 0.79, and 0.82) by means of hard x-ray photoemission spectroscopy (HAXPES). The HAXPES spectra clearly show distinct temperature dependencies in the spectral intensities of the Eu2 + and Eu3 +3 d components. For x =0.70 , the changes in the Eu2 + and Eu3 +3 d spectral components with temperature reflect a continuous valence transition, whereas the sudden changes for x =0.79 and 0.82 reflect first-order valence transitions. The Eu 3 d spectral shapes for all x and particularly the drastic changes in the Eu3 +3 d feature with temperature are validated by a theoretical calculation based on the single-impurity Anderson model (SIAM). SIAM analysis reveals that the valence transition for each x is controlled by the c -f hybridization strength and the charge-transfer energy. Furthermore, the c -f hybridization strength governs the valence transition of this system, which is either first order or continuous, consistent with Kondo volume collapse.

Assembly, Structure, and Functionality of Metal-Organic Networks and Organic Semiconductor Layers at Surfaces

Science.gov (United States)

Tempas, Christopher D.

Self-assembled nanostructures at surfaces show promise for the development of next generation technologies including organic electronic devices and heterogeneous catalysis. In many cases, the functionality of these nanostructures is not well understood. This thesis presents strategies for the structural design of new on-surface metal-organic networks and probes their chemical reactivity. It is shown that creating uniform metal sites greatly increases selectivity when compared to ligand-free metal islands. When O2 reacts with single-site vanadium centers, in redox-active self-assembled coordination networks on the Au(100) surface, it forms one product. When O2 reacts with vanadium metal islands on the same surface, multiple products are formed. Other metal-organic networks described in this thesis include a mixed valence network containing Pt0 and PtII and a network where two Fe centers reside in close proximity. This structure is stable to temperatures >450 °C. These new on-surface assemblies may offer the ability to perform reactions of increasing complexity as future heterogeneous catalysts. The functionalization of organic semiconductor molecules is also shown. When a few molecular layers are grown on the surface, it is seen that the addition of functional groups changes both the film's structure and charge transport properties. This is due to changes in both first layer packing structure and the pi-electron distribution in the functionalized molecules compared to the original molecule. The systems described in this thesis were studied using high-resolution scanning tunneling microscopy, non-contact atomic force microscopy, and X-ray photoelectron spectroscopy. Overall, this work provides strategies for the creation of new, well-defined on-surface nanostructures and adds additional chemical insight into their properties.

On γ5 in higher-order QCD calculations and the NNLO evolution of the polarized valence distribution

International Nuclear Information System (INIS)

Moch, S.; Vogt, A.

2015-06-01

We discuss the prescription for the Dirac matrix γ 5 in dimensional regularization used in most second- and third-order QCD calculations of collider cross sections. We provide an alternative implementation of this approach that avoids the use of an explicit form of γ 5 and of its (anti-) commutation relations in the most important case of no more than one γ 5 in each fermion trace. This treatment is checked by computing the third-order corrections to the structure functions F 2 and g 1 in charged-current deep-inelastic scattering with axial-vector couplings to the W-bosons. We derive the so far unknown third-order helicity-difference splitting function ΔP ns (2)s that contributes to the next-to-next-to-leading order (NNLO) evolution of the polarized valence quark distribution of the nucleon. This function is negligible at momentum fractions x>or similar 0.3 but relevant at x<<1.

NEVER forget: negative emotional valence enhances recapitulation.

Science.gov (United States)

Bowen, Holly J; Kark, Sarah M; Kensinger, Elizabeth A

2017-07-10

A hallmark feature of episodic memory is that of "mental time travel," whereby an individual feels they have returned to a prior moment in time. Cognitive and behavioral neuroscience methods have revealed a neurobiological counterpart: Successful retrieval often is associated with reactivation of a prior brain state. We review the emerging literature on memory reactivation and recapitulation, and we describe evidence for the effects of emotion on these processes. Based on this review, we propose a new model: Negative Emotional Valence Enhances Recapitulation (NEVER). This model diverges from existing models of emotional memory in three key ways. First, it underscores the effects of emotion during retrieval. Second, it stresses the importance of sensory processing to emotional memory. Third, it emphasizes how emotional valence - whether an event is negative or positive - affects the way that information is remembered. The model specifically proposes that, as compared to positive events, negative events both trigger increased encoding of sensory detail and elicit a closer resemblance between the sensory encoding signature and the sensory retrieval signature. The model also proposes that negative valence enhances the reactivation and storage of sensory details over offline periods, leading to a greater divergence between the sensory recapitulation of negative and positive memories over time. Importantly, the model proposes that these valence-based differences occur even when events are equated for arousal, thus rendering an exclusively arousal-based theory of emotional memory insufficient. We conclude by discussing implications of the model and suggesting directions for future research to test the tenets of the model.

A measurement of the proton structure functions from neutrino-hydrogen and antineutrino-hydrogen charged-current interactions

International Nuclear Information System (INIS)

Jones, G.T.; Jones, R.W.L.; Kennedy, B.W.; O'Neale, S.W.; Hamisi, F.; Miller, D.B.; Mobayyen, M.M.; Wainstein, S.; Corrigan, G.; Myatt, G.; Radojicic, D.; Shotton, P.N.; Towers, S.J.; Bullock, F.W.; Burke, S.

1989-01-01

Within the framework of the quark-parton model, the quark and anti-quark structure functions of the proton have been measured by fitting them to the distributions of the events in the Bjorken y variable. The data used form the largest sample of neutrino and antineutrino interactions on a pure hydrogen target available, and come from exposures of BEBC to the CERN wide band neutrino and antineutrino beams. It is found that the ratio d ν /u ν of valence quark distributions falls with increasing Bjorken x. In the context of the quark-parton model the results constrain the isospin composition of the accompanying diquark system. Models involving scattering from diquarks are in disagreement with the data. (orig.)

Multilevel analysis of facial expressions of emotion and script: self-report (arousal and valence) and psychophysiological correlates.

Science.gov (United States)

Balconi, Michela; Vanutelli, Maria Elide; Finocchiaro, Roberta

2014-09-26

The paper explored emotion comprehension in children with regard to facial expression of emotion. The effect of valence and arousal evaluation, of context and of psychophysiological measures was monitored. Indeed subjective evaluation of valence (positive vs. negative) and arousal (high vs. low), and contextual (facial expression vs. facial expression and script) variables were supposed to modulate the psychophysiological responses. Self-report measures (in terms of correct recognition, arousal and valence attribution) and psychophysiological correlates (facial electromyography, EMG, skin conductance response, SCR, and heart rate, HR) were observed when children (N = 26; mean age = 8.75 y; range 6-11 y) looked at six facial expressions of emotions (happiness, anger, fear, sadness, surprise, and disgust) and six emotional scripts (contextualized facial expressions). The competencies about the recognition, the evaluation on valence and arousal was tested in concomitance with psychophysiological variations. Specifically, we tested for the congruence of these multiple measures. Log-linear analysis and repeated measure ANOVAs showed different representations across the subjects, as a function of emotion. Specifically, children' recognition and attribution were well developed for some emotions (such as anger, fear, surprise and happiness), whereas some other emotions (mainly disgust and sadness) were less clearly represented. SCR, HR and EMG measures were modulated by the evaluation based on valence and arousal, with increased psychophysiological values mainly in response to anger, fear and happiness. As shown by multiple regression analysis, a significant consonance was found between self-report measures and psychophysiological behavior, mainly for emotions rated as more arousing and negative in valence. The multilevel measures were discussed at light of dimensional attribution model.

Characterization of MBE-grown InAlN/GaN heterostructure valence band offsets with varying In composition

Energy Technology Data Exchange (ETDEWEB)

Jiao, Wenyuan, E-mail: wyjiaonju@gmail.com; Kong, Wei; Li, Jincheng; Kim, Tong-Ho; Brown, April S. [Department of Electrical and Computer Engineering, Duke University, Durham, NC, 27708 (United States); Collar, Kristen [Department of Physics, Duke University, Durham, NC, 27708 (United States); Losurdo, Maria [CNR-NANOTEC, Istituto di Nanotecnologia, via Orabona, 4-70126 Bari (Italy)

2016-03-15

Angle-resolved X-ray photoelectron spectroscopy (XPS) is used in this work to experimentally determine the valence band offsets of molecular beam epitaxy (MBE)-grown InAlN/GaN heterostructures with varying indium composition. We find that the internal electric field resulting from polarization must be taken into account when analyzing the XPS data. Valence band offsets of 0.12 eV for In{sub 0.18}Al{sub 0.82}N, 0.15 eV for In{sub 0.17}Al{sub 0.83}N, and 0.23 eV for In{sub 0.098}Al{sub 0.902}N with GaN are obtained. The results show that a compositional-depended bowing parameter is needed in order to estimate the valence band energies of InAlN as a function of composition in relation to those of the binary endpoints, AlN and InN.

Characterization of MBE-grown InAlN/GaN heterostructure valence band offsets with varying In composition

Directory of Open Access Journals (Sweden)

Wenyuan Jiao

2016-03-01

Full Text Available Angle-resolved X-ray photoelectron spectroscopy (XPS is used in this work to experimentally determine the valence band offsets of molecular beam epitaxy (MBE-grown InAlN/GaN heterostructures with varying indium composition. We find that the internal electric field resulting from polarization must be taken into account when analyzing the XPS data. Valence band offsets of 0.12 eV for In0.18Al0.82N, 0.15 eV for In0.17Al0.83N, and 0.23 eV for In0.098Al0.902N with GaN are obtained. The results show that a compositional-depended bowing parameter is needed in order to estimate the valence band energies of InAlN as a function of composition in relation to those of the binary endpoints, AlN and InN.

Sex differences in brain activation patterns during processing of positively and negatively valenced emotional words.

Science.gov (United States)

Hofer, Alex; Siedentopf, Christian M; Ischebeck, Anja; Rettenbacher, Maria A; Verius, Michael; Felber, Stephan; Wolfgang Fleischhacker, W

2007-01-01

Previous studies have suggested that men and women process emotional stimuli differently. In this study, we used event-related functional magnetic resonance imaging (fMRI) to investigate gender differences in regional cerebral activity during the perception of positive or negative emotions. The experiment comprised two emotional conditions (positively/negatively valenced words) during which fMRI data were acquired. Thirty-eight healthy volunteers (19 males, 19 females) were investigated. A direct comparison of brain activation between men and women revealed differential activation in the right putamen, the right superior temporal gyrus, and the left supramarginal gyrus during processing of positively valenced words versus non-words for women versus men. By contrast, during processing of negatively valenced words versus non-words, relatively greater activation was seen in the left perirhinal cortex and hippocampus for women versus men, and in the right supramarginal gyrus for men versus women. Our findings suggest gender-related neural responses to emotional stimuli and could contribute to the understanding of mechanisms underlying the gender disparity of neuropsychiatric diseases such as mood disorders.

Effects of valence and divided attention on cognitive reappraisal processes.

Science.gov (United States)

Morris, John A; Leclerc, Christina M; Kensinger, Elizabeth A

2014-12-01

Numerous studies have investigated the neural substrates supporting cognitive reappraisal, identifying the importance of cognitive control processes implemented by prefrontal cortex (PFC). This study examined how valence and attention affect the processes used for cognitive reappraisal by asking participants to passively view or to cognitively reappraise positive and negative images with full or divided attention. When participants simply viewed these images, results revealed few effects of valence or attention. However, when participants engaged in reappraisal, there was a robust effect of valence, with the reappraisal of negative relative to positive images associated with more widespread activation, including within regions of medial and lateral PFC. There also was an effect of attention, with more lateral PFC recruitment when regulating with full attention and more medial PFC recruitment when regulating with divided attention. Within two regions of medial PFC and one region of ventrolateral PFC, there was an interaction between valence and attention: in these regions, divided attention reduced activity during reappraisal of positive but not negative images. Critically, participants continued to report reappraisal success even during the Divided Attention condition. These results suggest multiple routes to successful cognitive reappraisal, depending upon image valence and the availability of attentional resources. © The Author (2014). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Effects of valence and divided attention on cognitive reappraisal processes

Science.gov (United States)

Leclerc, Christina M.; Kensinger, Elizabeth A.

2014-01-01

Numerous studies have investigated the neural substrates supporting cognitive reappraisal, identifying the importance of cognitive control processes implemented by prefrontal cortex (PFC). This study examined how valence and attention affect the processes used for cognitive reappraisal by asking participants to passively view or to cognitively reappraise positive and negative images with full or divided attention. When participants simply viewed these images, results revealed few effects of valence or attention. However, when participants engaged in reappraisal, there was a robust effect of valence, with the reappraisal of negative relative to positive images associated with more widespread activation, including within regions of medial and lateral PFC. There also was an effect of attention, with more lateral PFC recruitment when regulating with full attention and more medial PFC recruitment when regulating with divided attention. Within two regions of medial PFC and one region of ventrolateral PFC, there was an interaction between valence and attention: in these regions, divided attention reduced activity during reappraisal of positive but not negative images. Critically, participants continued to report reappraisal success even during the Divided Attention condition. These results suggest multiple routes to successful cognitive reappraisal, depending upon image valence and the availability of attentional resources. PMID:24493837

Pressure-induced changes in the electronic structure of americium metal

Science.gov (United States)

Söderlind, Per; Moore, K. T.; Landa, A.; Sadigh, B.; Bradley, J. A.

2011-08-01

We have conducted electronic-structure calculations for Am metal under pressure to investigate the behavior of the 5f-electron states. Density-functional theory (DFT) does not reproduce the experimental photoemission spectra for the ground-state phase where the 5f electrons are localized, but the theory is expected to be correct when 5f delocalization occurs under pressure. The DFT prediction is that peak structures of the 5f valence band will merge closer to the Fermi level during compression indicating the presence of itinerant 5f electrons. Existence of such 5f bands is argued to be a prerequisite for the phase transitions, particularly to the primitive orthorhombic AmIV phase, but does not agree with modern dynamical-mean-field theory (DMFT) results. Our DFT model further suggests insignificant changes of the 5f valence under pressure in agreement with recent resonant x-ray emission spectroscopy, but in contradiction to the DMFT predictions. The influence of pressure on the 5f valency in the actinides is discussed and is shown to depend in a nontrivial fashion on 5f-band position and occupation relative to the spd valence bands.

Valence electron structure analysis of the cubic silicide intermetallics in rapidly solidified Al-Fe-V-Si alloy

International Nuclear Information System (INIS)

Wang, J.Q.; Qian, C.F.; Zhang, B.J.; Tseng, M.K.; Xiong, S.W.

1996-01-01

The application of rapid solidification for the development of elevated temperature aluminum alloys has resulted in the emergence of several alloys based on the Al-Fe alloy system. Of particular interest are Al-Fe-V-Si alloys which have excellent room temperature and high temperature mechanical properties. In a pioneering study, Skinner et al. showed the stabilization of the cubic phase in ternary Al-Fe-Si alloy by the addition of a quaternary element, vanadium. The evolution of the microstructure in these alloys both during rapid solidification and subsequent processing is of crucial importance. Kim has demonstrated that the composition of the silicide phase in rapidly solidified Al-Fe-V-Si alloy is very close to Al 12 (Fe,V) 3 Si with the body centered cubic (bcc) structure. The structure is closely related to that of quasicrystals.In view of the structural features and the relationship between the α 12 and α 13 phases, the researching emphasis should firstly be put on the α 12 phase. In this paper the authors analyzed the α -(AlFeSi)(α 12 -type) phase from the angle of atomic valence electron structure other than the traditional methods of obtaining the diffraction spots of the phase. Several pieces of information were obtained about the hybrid levels and bond natures of every kind of atom in the α -(AlFeSi) phase. Finally the authors explained the phenomenon which V atom can substitute for Fe atom in the α 12 phase and improve the thermal stability of the phase in Al-Fe-V-Si alloy

Hadronic Structure from Perturbative Dressing

Energy Technology Data Exchange (ETDEWEB)

Arash, Firooz [Physics Department, Tafresh University, Tafresh, Iran and Center for theoretical physics and Mathematics, AEOI, P.O. Box 11365-8486, Tehran (Iran, Islamic Republic of)]. E-mail: farash@cic.aut.ac.ir

2005-09-15

Perturbative dressing of a valence quark in QCD produces the internal structure of an extended object, the so-called Valon. The valon structure is universal and independent of the hosting hadron. Polarized and unpolarized proton and pion structure functions are calculated in the valon representation. One finds that although all the available data on g{sub 1}{sup p,n,d} are easily reproduced, a sizable orbital angular momentum associated with the partonic structure of the valon is required in order to have a spin 1/2 valon.

Memory effects of sleep, emotional valence, arousal and novelty in children.

Science.gov (United States)

Vermeulen, Marije C M; van der Heijden, Kristiaan B; Benjamins, Jeroen S; Swaab, Hanna; van Someren, Eus J W

2017-06-01

Effectiveness of memory consolidation is determined by multiple factors, including sleep after learning, emotional valence, arousal and novelty. Few studies investigated how the effect of sleep compares with (and interacts with) these other factors, of which virtually none are in children. The present study did so by repeated assessment of declarative memory in 386 children (45% boys) aged 9-11 years through an online word-pair task. Children were randomly assigned to either a morning or evening learning session of 30 unrelated word-pairs with positive, neutral or negative valenced cues and neutral targets. After immediately assessing baseline recognition, delayed recognition was recorded either 12 or 24 h later, resulting in four different assessment schedules. One week later, the procedure was repeated with exactly the same word-pairs to evaluate whether effects differed for relearning versus original novel learning. Mixed-effect logistic regression models were used to evaluate how the probability of correct recognition was affected by sleep, valence, arousal, novelty and their interactions. Both immediate and delayed recognition were worse for pairs with negatively valenced or less arousing cue words. Relearning improved immediate and delayed word-pair recognition. In contrast to these effects, sleep did not affect recognition, nor did sleep moderate the effects of arousal, valence and novelty. The findings suggest a robust inclination of children to specifically forget the pairing of words to negatively valenced cue words. In agreement with a recent meta-analysis, children seem to depend less on sleep for the consolidation of information than has been reported for adults, irrespective of the emotional valence, arousal and novelty of word-pairs. © 2017 European Sleep Research Society.

Titanium, vanadium and chromium valences in silicates of ungrouped achondrite NWA 7325 and ureilite Y-791538 record highly-reduced origins

Science.gov (United States)

Sutton, S. R.; Goodrich, C. A.; Wirick, S.

2017-05-01

Titanium, Cr, and V valences were determined by applying micro-X-ray Absorption Near Edge Structure (micro-XANES) spectroscopy methods to individual grains of olivine and pyroxene in the ungrouped achondrite NWA 7325 and ureilite Y-791538, as well as to plagioclase in NWA 7325. The advantages of applying multiple, multivalent-element-based oxybarometers to individual grains are (1) the ability to cover the entire oxygen fugacity (fO2) range encountered in nature, and (2) the increased reliability from consistent results for semi-independent fO2 proxies. fO2 values were inferred from each mineral valence determination after correcting with available laboratory-experiment-derived, valence-specific partition coefficients to obtain melt valences and then calibrating with the fO2 values of the relevant equal species proportions points suggested for igneous (primarily basaltic) systems. The resulting olivine and pyroxene valences are highly reduced and similar in the two meteorites with substantial fractions of Cr2+, Ti3+ and V2+. The exception is Cr in NWA 7325 pyroxene which is much more oxidized than the Cr in its olivine. Chromium and Ti in plagioclase in NWA 7325 is relatively oxidized (V valence not determined). The anomalously oxidized Cr in NWA 7325 pyroxene may be due to a secondary reheating event that oxidized Cr in the pyroxene without similarly oxidizing Ti and V. Such a separation of the redox couples may be an effect of re-equilibration kinetics, where the valence of Cr would be more rapidly modified. These valences yielded similar mean fO2s for the two meteorites; IW-3.1 ± 0.2 for NWA 7325 and IW-2.8 ± 0.2 for Y-791538, consistent with an origin of NWA 7325 in either Mercury or an asteroid that experienced redox conditions similar to those on the ureilite parent body.

Proton spin structure in the rest frame

International Nuclear Information System (INIS)

Zavada, P.

1997-01-01

It is shown that the quark-parton model in the standard infinite momentum approach overestimates the proton spin structure function g 1 (x) in comparison with the approach taking consistently into account the internal motion of quarks described by a spherical phase space in the proton rest frame. Particularly, it is shown the first moment of the spin structure function in the latter approach, assuming only the valence quarks contribution to the proton spin, does not contradict the experimental data. copyright 1997 The American Physical Society

Investigating Valence and Autonomy in Children's Relationships with Imaginary Companions

Science.gov (United States)

McInnis, Melissa A.; Pierucci, Jillian M.; Gilpin, Ansley Tullos

2013-01-01

Little research has explored valence and autonomy in children's imaginary relationships. In the present study, a new interview (modeled after an existing measure for real relationships) was designed to elicit descriptions of both positive and negative interactions with imaginary companions and to provide a measure of relationship valence and…

Electronic structure of multiferroic BiFeO3 by resonant soft-x-ray emission spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Higuchi, Tohru; Higuchi, T.; Liu, Y.-S.; Yao, P.; Glans, P.-A.; Guo, Jinghua; Chang, C.; Wu, Z.; Sakamoto, W.; Itoh, N.; Shimura, T.; Yogo, T.; Hattori, T.

2008-07-11

The electronic structure of multiferroic BiFeO{sub 3} has been studied using soft-X-ray emission spectroscopy. The fluorescence spectra exhibit that the valence band is mainly composed of O 2p state hybridized with Fe 3d state. The band gap corresponding to the energy separation between the top of the O 2p valence band and the bottom of the Fe 3d conduction band is 1.3 eV. The soft-X-ray Raman scattering reflects the features due to charge transfer transition from O 2p valence band to Fe 3d conduction band. These findings are similar to the result of electronic structure calculation by density functional theory within the local spin-density approximation that included the effect of Coulomb repulsion between localized d states.

Valence-band and core-level photoemission study of single-crystal Bi2CaSr2Cu2O8 superconductors

International Nuclear Information System (INIS)

Shen, Z.; Lindberg, P.A.P.; Wells, B.O.; Mitzi, D.B.; Lindau, I.; Spicer, W.E.; Kapitulnik, A.

1988-01-01

High-quality single crystals of Bi 2 CaSr 2 Cu 2 O 8 superconductors have been prepared and cleaved in ultrahigh vacuum. Low-energy electron diffraction measurements show that the surface structure is consistent with the bulk crystal structure. Ultraviolet photoemission and x-ray photoemission experiments were performed on these well-characterized sample surfaces. The valence-band and the core-level spectra obtained from the single-crystal surfaces are in agreement with spectra recorded from polycrystalline samples, justifying earlier results from polycrystalline samples. Cu satellites are observed both in the valence band and Cu 2p core level, signaling the strong correlation among the Cu 3d electrons. The O 1s core-level data exhibit a sharp, single peak at 529-eV binding energy without any clear satellite structures

Valence configurations in 214Rn

International Nuclear Information System (INIS)

Dracoulis, G.D.; Byrne, A.P.; Stuchbery, A.E.; Bark, R.A.; Poletti, A.R.

1987-01-01

Excited states of 214 Rn, up to spins of ≅ 24 ℎ have been studied using γ-ray and electron spectroscopy following the 208 Pb( 9 Be,3n) 214 Rn reaction. The level scheme (which differs substantially from earlier work) is compared with the results of a semi-empirical shell model calculation. The availability of high-spin orbitals for the four valence protons and two valence neutrons, and the effect of the attractive proton-neutron interaction, leads to the prediction of high-spin states at an unusually low excitation energy. Experimentally, the high level density leads to difficulties in the level scheme assignments at high spin. Nevertheless, configuration assignments, supported by transition strengths deduced from the measured lifetimes (in the nanosecond region) are suggested for the main yrast states. The decay properties also suggest that configuration mixing is important. The possibility of a gradual transition to octupole deformation, implied by the decay properties of the 11 - and 10 + yrast states is also discussed. (orig.)

Differences in neural activity when processing emotional arousal and valence in autism spectrum disorders.

Science.gov (United States)

Tseng, Angela; Wang, Zhishun; Huo, Yuankai; Goh, Suzanne; Russell, James A; Peterson, Bradley S

2016-02-01

Individuals with autism spectrum disorders (ASD) often have difficulty recognizing and interpreting facial expressions of emotion, which may impair their ability to navigate and communicate successfully in their social, interpersonal environments. Characterizing specific differences between individuals with ASD and their typically developing (TD) counterparts in the neural activity subserving their experience of emotional faces may provide distinct targets for ASD interventions. Thus we used functional magnetic resonance imaging (fMRI) and a parametric experimental design to identify brain regions in which neural activity correlated with ratings of arousal and valence for a broad range of emotional faces. Participants (51 ASD, 84 TD) were group-matched by age, sex, IQ, race, and socioeconomic status. Using task-related change in blood-oxygen-level-dependent (BOLD) fMRI signal as a measure, and covarying for age, sex, FSIQ, and ADOS scores, we detected significant differences across diagnostic groups in the neural activity subserving the dimension of arousal but not valence. BOLD-signal in TD participants correlated inversely with ratings of arousal in regions associated primarily with attentional functions, whereas BOLD-signal in ASD participants correlated positively with arousal ratings in regions commonly associated with impulse control and default-mode activity. Only minor differences were detected between groups in the BOLD signal correlates of valence ratings. Our findings provide unique insight into the emotional experiences of individuals with ASD. Although behavioral responses to face-stimuli were comparable across diagnostic groups, the corresponding neural activity for our ASD and TD groups differed dramatically. The near absence of group differences for valence correlates and the presence of strong group differences for arousal correlates suggest that individuals with ASD are not atypical in all aspects of emotion-processing. Studying these similarities

Spin and spinless conductivity in polypyrrole. Evidence for mixed-valence conduction

Energy Technology Data Exchange (ETDEWEB)

Zotti, G.; Schiavon, G. (Ist. di Polarografia ed Elettrochimica Preparativa, Padova (Italy))

In situ conductivity of polypyrrole (as tosylate) as a function of oxidative doping level attains a maximum at three-quarters the total oxidation charge and the relevant in situ ESR signal corresponds to an equal concentration of spin-carrying (polaron) and spinless (bipolaron) species. Results are explained on the basis of mixed-valence conduction. Bipolaron conduction, taking the place of polaron-bipolaron conductivity at higher oxidation levels, accounts for persisting conductivity in the high-oxidation state.

Direct double photoionization of the valence shell of Be

International Nuclear Information System (INIS)

Citrini, F.; Malegat, L.; Selles, P.; Kazansky, A.K.

2003-01-01

The hyperspherical R-matrix method with semiclassical outgoing waves is used to study the direct double photoionization (DPI) of the valence shell of the lightest alkaline earth-metal Be. The absolute fully integrated, singly, doubly, and triply differential cross sections obtained are compared with the single set of measurements available and with recent calculations based on the convergent close coupling and time-dependent close coupling methods. The level of agreement between all these data is very encouraging. A comparison is also made between the DPI of He and the direct DPI of the valence shell of Be. It confirms that the electron-electron correlations are stronger in the valence 2s shell of Be than in the 1s shell of He, thus contributing to a desirable clarification

Magneto-optical studies of valence instability in europium and terbium phosphors

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, Lucas C.V. [Department of Chemistry, University of Turku, FI-20014 Turku (Finland); Instituto de Química, Universidade de São Paulo, São Paulo, -SP (Brazil); Hölsä, Jorma [Department of Chemistry, University of Turku, FI-20014 Turku (Finland); Instituto de Química, Universidade de São Paulo, São Paulo, -SP (Brazil); Turku University Centre for Materials and Surfaces (MatSurf) (Finland); University of the Free State, Department of Physics, Bloemfontein (South Africa); Brito, Hermi F. [Instituto de Química, Universidade de São Paulo, São Paulo, -SP (Brazil); Maryško, Miroslav [Institute of Physics, The Academy of Sciences of the Czech Republic, Cukrovarnická 10, CZ-162 53 Praha 6 (Czech Republic); Matos, Jivaldo R. [Instituto de Química, Universidade de São Paulo, São Paulo, -SP (Brazil); Paturi, Petriina [Wihuri Physical Laboratory, Department of Physics and Astronomy, University of Turku, FI-20014 Turku (Finland); Rodrigues, Rodrigo V. [Instituto de Química, Universidade de São Paulo, São Paulo, -SP (Brazil); Lastusaari, Mika, E-mail: miklas@utu.fi [Department of Chemistry, University of Turku, FI-20014 Turku (Finland); Turku University Centre for Materials and Surfaces (MatSurf) (Finland)

2016-02-15

The impurities and dopants' inappropriate valences may deteriorate the performance of luminescent materials, cause waste of the precious rare earth (R) material and thus incur financial losses. The usual methods to detect the valence of rare earths; XPS, Mössbauer and XANES spectroscopies, are not sensitive enough for low concentrations and the EPR methods are not very suitable for powders. In this work, the comparison between the theoretical and experimental temperature-dependent paramagnetic susceptibilities was used to obtain quantitatively the concentrations of the impurity valence in Eu{sub 2}O{sub 2}S and Tb{sub 2}O{sub 2}SO{sub 4}, both containing nominally only R{sup 3+}. Minute (ppm level) Eu{sup 2+} impurities could be analyzed because of the huge difference in the paramagnetic susceptibility between Eu{sup 2+} and Eu{sup 3+} at low temperatures. However, temperatures below 50 K are then needed whilst the Tb{sup IV} impurity in a Tb{sup 3+} matrix can be observed already at higher temperatures. The latter method based on comparing the slopes of the Tb{sup 3+}/Tb{sup IV} paramagnetic susceptibility vs temperature curves for the Tb{sup 3+}/Tb{sup IV} couple is less sensitive than for the Eu{sup 2+}/Eu{sup 3+} one. Finally, the host independent temperature evolution of the paramagnetic susceptibility was calculated for Gd{sup 3+} (or Eu{sup 2+} or Tb{sup IV}) to yield a simple analytical expression to be used universally. - Highlights: • Wave functions for Eu{sup 3+}/Tb{sup 3+} with crystal field effect calculated for oxysulfide/sulfate. • Paramagnetic susceptibility between 4 and 300 K simulated for 4f{sup 6/7/8} configurations. • Amount of valence impurities (Eu{sup 2+} and Tb{sup IV}) evaluated from susceptibility data. • Waste of raw materials and loss of luminescence intensity of phosphors can be avoided.

Organization of Valence-Encoding and Projection-Defined Neurons in the Basolateral Amygdala

Directory of Open Access Journals (Sweden)

Anna Beyeler

2018-01-01

Full Text Available The basolateral amygdala (BLA mediates associative learning for both fear and reward. Accumulating evidence supports the notion that different BLA projections distinctly alter motivated behavior, including projections to the nucleus accumbens (NAc, medial aspect of the central amygdala (CeM, and ventral hippocampus (vHPC. Although there is consensus regarding the existence of distinct subsets of BLA neurons encoding positive or negative valence, controversy remains regarding the anatomical arrangement of these populations. First, we map the location of more than 1,000 neurons distributed across the BLA and recorded during a Pavlovian discrimination task. Next, we determine the location of projection-defined neurons labeled with retrograde tracers and use CLARITY to reveal the axonal path in 3-dimensional space. Finally, we examine the local influence of each projection-defined populations within the BLA. Understanding the functional and topographical organization of circuits underlying valence assignment could reveal fundamental principles about emotional processing.

Chromium valences in ureilite olivine and implications for ureilite petrogenesis

Science.gov (United States)

Goodrich, C. A.; Sutton, S. R.; Wirick, S.; Jercinovic, M. J.

2013-12-01

Ureilites are a group of ultramafic achondrites commonly thought to be residues of partial melting on a carbon-rich asteroid. They show a large variation in FeO content (olivine Fo values ranging from ∼74 to 95) that cannot be due to igneous fractionation and suggests instead variation in oxidation state. The presence of chromite in only a few of the most ferroan (Fo 75-76) samples appears to support such a model. MicroXANES analyses were used in this study to determine the valence states of Cr (previously unknown) in olivine cores of 11 main group ureilites. The goal of this work was to use a method that is independent of Fo to determine the oxidation conditions under which ureilites formed, in order to evaluate whether the ureilite FeO-variation is correlated with oxidation state, and whether it is nebular or planetary in origin. Two of the analyzed samples, LEW 88774 (Fo 74.2) and NWA 766 (Fo 76.7) contain primary chromite; two others, LAP 03587 (Fo 74.4) and CMS 04048 (Fo 76.2) contain sub-micrometer-sized exsolutions of chromite + Ca-rich pyroxene in olivine; and one, EET 96328 (Fo 85.2) contains an unusual chromite grain of uncertain origin. No chromite has been observed in the remaining six samples (Fo 77.4-92.3). Chromium in olivine in all eleven samples was found to be dominated by the divalent species, with valences ranging from 2.10 ± 0.02 (1σ) to 2.46 ± 0.04. The non-chromite-bearing ureilites have the most reduced Cr, with a weighted mean valence of 2.12 ± 0.01, i.e., Cr2+/Cr3+ = 7.33. All low-Fo chromite-bearing ureilites have more oxidized Cr, with valences ranging from 2.22 ± 0.03 to 2.46 ± 0.04. EET 96328, whose chromite grain we interpret as a late-crystallizing phase, yielded a reduced Cr valence of 2.15 ± 0.07, similar to the non-chromite-bearing samples. Based on the measured Cr valences, magmatic (1200-1300 °C) oxygen fugacities (fO2) of the non-chromite-bearing samples were estimated to be in the range IW-1.9 to IW-2.8 (assuming

B-site cation order/disorder and their valence states in Ba3MnNb2O9 perovskite oxide

Science.gov (United States)

Xin, Yan; Huang, Qing; Shafieizadeh, Zahra; Zhou, Haidong

2018-06-01

Polycrystalline samples Ba3MnNb2O9 synthesized by solid state reaction and single crystal samples grown by optical floating zone have been characterized using scanning transmission electron microscopy and electron energy loss spectroscopy. Three types of B-site Mn and Nb ordering phase are observed: fully ordered 1Mn:2Nb; fully disordered; nano-sized 1Mn:1Nb ordered. No electronic structure change for crystals with different ordering/disordering. The Mn valence is determined to be 2+, and Nb valence is 5+. Oxygen 2p orbitals hybridize with Mn 3d and Nb 4d orbitals. Factors that affect the electron energy loss near edge structures of transition metal white-lines in electron energy loss spectroscopy are explicitly illustrated and discussed.

A preliminary study on Fe valence of porcelain glaze by XAFS

International Nuclear Information System (INIS)

Zhang Maolin; Wang Changsui; Jin Pujun; Wei Shiqiang; Xu Wei; Chen Dongliang; Wu Ziyu

2008-01-01

Ru ware was a famous celadon in Song dynasty, whose structure analysis of glaze had always been a difficulty in scientifically analysis of ancient porcelains. The X-ray absorption fine structure spectrum (XAFS) of Fe element in glaze of Ru ware excavated in Qingliang temple was obtained. Fe valence state in porcelain glaze samples was stud/ed by Principle Component Analysis (PCA) along with linear combination fitting method. The main wavelength of the samples was also obtained by color/meter. The results show that the cyan glaze samples have great Fe 2+ /Fe 3+ , while the yellow glaze samples have small Fe 2+ /Fe 3+ . The work also showed that X-ray absorption fine structure spectrum was very suitable in nondestructive analysis of ancient ceramics. (authors)

Valence band offset of β-Ga2O3/wurtzite GaN heterostructure measured by X-ray photoelectron spectroscopy.

Science.gov (United States)

Wei, Wei; Qin, Zhixin; Fan, Shunfei; Li, Zhiwei; Shi, Kai; Zhu, Qinsheng; Zhang, Guoyi

2012-10-10

A sample of the β-Ga2O3/wurtzite GaN heterostructure has been grown by dry thermal oxidation of GaN on a sapphire substrate. X-ray diffraction measurements show that the β-Ga2O3 layer was formed epitaxially on GaN. The valence band offset of the β-Ga2O3/wurtzite GaN heterostructure is measured by X-ray photoelectron spectroscopy. It is demonstrated that the valence band of the β-Ga2O3/GaN structure is 1.40 ± 0.08 eV.

Magnetic properties of mixed valence La2/3Sr1/3Mn1−xTxO3 (T ...

Indian Academy of Sciences (India)

(T = Fe,Cr) manganites obtained by Pechini method. I BETANCOURT. ∗ ... structure. Keywords. Mixed valence manganites; magnetic manganites; magnetocaloric effect; Pechini method. 1. ..... IB thanks for financial support from research grant.

Negative pressure driven valence instability of Eu in cubic Eu{sub 0.4}La{sub 0.6}Pd{sub 3}

Energy Technology Data Exchange (ETDEWEB)

Pandey, Abhishek [S N Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata-700098 (India); Mazumdar, Chandan; Ranganathan, R [Experimental Condensed Matter Physics Division, Saha Institute of Nuclear Physics, 1/AF, Bidhannagar, Kolkata-700064 (India)], E-mail: abhishek.phy@gmail.com, E-mail: chandan.mazumar@saha.ac.in

2009-05-27

We report the change in the valency of Eu-ions in the binary intermetallic cubic compound EuPd{sub 3} induced by La doping at rare-earth sites. Doping of La generates negative chemical pressure in the lattice, resulting in a significant increase of the lattice parameter without altering the simple-cubic structure of the compound. Results of dc-magnetic measurements suggest that this increase in the lattice parameter is associated with the valence transition of Eu-ions from Eu{sup 3+} to a mixed-valent state. As Eu{sup 2+}-ions possess a large magnetic moment, this valence transition significantly modifies the magnetic behavior of the compound. In contrast to introducing boron at the vacant body center site of the unit cell to change the valency of Eu-ions, as in the case of EuPd{sub 3}B, our results suggest it can also be altered by doping a rare-earth ion of larger size at the lattice site of Eu in EuPd{sub 3}.

Valence band offset of wurtzite InN/SrTiO3 heterojunction measured by x-ray photoelectron spectroscopy

Directory of Open Access Journals (Sweden)

Li Zhiwei

2011-01-01

Full Text Available Abstract The valence band offset (VBO of wurtzite indium nitride/strontium titanate (InN/SrTiO3 heterojunction has been directly measured by x-ray photoelectron spectroscopy. The VBO is determined to be 1.26 ± 0.23 eV and the conduction band offset is deduced to be 1.30 ± 0.23 eV, indicating the heterojunction has a type-I band alignment. The accurate determination of the valence and conduction band offsets paves a way to the applications of integrating InN with the functional oxide SrTiO3.

Valence electron structure and bonding features of RuB2 and OSB2: The empirical electron theory calculations

Institute of Scientific and Technical Information of China (English)

无

2010-01-01

The valence electron structure (VES) of RuB2 and OsB2 were calculated by the empirical electron theory (EET) of solids and molecules and compared with the results derived from the first-principles calculations. The distributions of covalent electrons in different bonds indicate that B-B and B-Me have remarkably covalent bonding characters. Lattice electrons cruising around Me-Me layers are found to have great influences on electronic conductivity and high temperature plasticity. The ultra-high values of elastic constant Cn in the two compounds originate from close-packed covalent bonding along the c axis. Uneven bond strengths and distributions of covalent bonds, especially for B-Afe bonds, yield significant anisotropy. Low ratios of lattice electrons to covalent electrons suggest the intrinsic embrittlement in crystals. The fact that the calculated cohesive energies well agree with experimental results demonstrates the good suitability of the EET calculations in estimating cohesive energy for transition-metal borides.

RKKY interaction in mixed valence system and heavy fermion superconductivity

International Nuclear Information System (INIS)

Fusui Liu; Gao Lin; Lin Zonghan

1985-11-01

The 1-D RKKY interaction of mixed valence system is given by using the thermodynamic perturbation theory. The numerical comparisons of 1-D and 3-D RKKY interaction between systems with localized magnetic moments of mixed valence and non-mixed valence show that the former is much stronger than the latter. From some analyses we propose that the heavy Fermion superconductivity comes from the RKKY interaction between two local f electrons which hop off the impurity site to become two continuum electrons. The source of the two impurity electrons hopping is the Coulomb interaction. It is also emphasized that the RKKY interaction does not disappear for the Kondo lattice, when the temperature is less than the Kondo temperature. (author)

Emotional ties that bind: the roles of valence and consistency of group emotion in inferences of cohesiveness and common fate.

Science.gov (United States)

Magee, Joe C; Tiedens, Larissa Z

2006-12-01

In three studies, observers based inferences about the cohesiveness and common fate of groups on the emotions expressed by group members. The valence of expressions affected cohesiveness inferences, whereas the consistency of expressions affected inferences of whether members have common fate. These emotion composition effects were stronger than those due to the race or sex composition of the group. Furthermore, the authors show that emotion valence and consistency are differentially involved in judgments about the degree to which the group as a whole was responsible for group performance. Finally, it is demonstrated that valence-cohesiveness effects are mediated by inferences of interpersonal liking and that consistency-common fate effects are mediated by inferences of psychological similarity. These findings have implications for the literature on entitativity and regarding the function of emotions in social contexts.

Valence band electronic structure of Ho-doped La0.67Ca0.33MnO3 using ultra-violet photoemission spectroscopy

Science.gov (United States)

Rout, S. K.; Mukharjee, R. N.; Mishra, D. K.; Roul, B. K.; Sekhar, B. R.; Dalai, M. K.

2017-05-01

In this manuscript we report the valence band electronic structure of Ho doped La0.67Ca0.33MnO3 using ultraviolet photoemission spectroscopy. We compared the density of states of La0.67Ca0.33MnO3, La0.67Ca0.3Ho0.03MnO3 and La0.64Ho0.03Ca0.33MnO3 near the Fermi level at various temperatures. Significant amount of changes have been observed at higher temperatures (220 K and 300 K) where the near Fermi level density of states increases with Ho doping into La0.67Ca0.33MnO3 indicating the enhancement of magnitude of change in metallicity (conductivity).

Determination of the impact of Bi content on the valence band energy of GaAsBi using x-ray photoelectron spectroscopy

Directory of Open Access Journals (Sweden)

K. Collar

2017-07-01

Full Text Available We investigate the change of the valence band energy of GaAs1-xBix (0function of dilute bismuth (Bi concentration, x, using x-ray photoelectron spectroscopy (XPS. The change in the valence band energy per addition of 1 % Bi is determined for strained and unstrained thin films using a linear approximation applicable to the dilute regime. Spectroscopic ellipsometry (SE was used as a complementary technique to determine the change in GaAsBi bandgap resulting from Bi addition. Analysis of SE and XPS data together supports the conclusion that ∼75% of the reduction in the bandgap is in the valence band for a compressively strained, dilute GaAsBi thin film at room temperature.

High spin structure functions

International Nuclear Information System (INIS)

Khan, H.

1990-01-01

This thesis explores deep inelastic scattering of a lepton beam from a polarized nuclear target with spin J=1. After reviewing the formation for spin-1/2, the structure functions for a spin-1 target are defined in terms of the helicity amplitudes for forward compton scattering. A version of the convolution model, which incorporates relativistic and binding energy corrections is used to calculate the structure functions of a neutron target. A simple parameterization of these structure functions is given in terms of a few neutron wave function parameters and the free nucleon structure functions. This allows for an easy comparison of structure functions calculated using different neutron models. (author)

Tuning the electronic structure and transport properties of graphene by noncovalent functionalization: effects of organic donor, acceptor and metal atoms

International Nuclear Information System (INIS)

Zhang Yonghui; Zhou Kaige; Xie Kefeng; Zeng Jing; Zhang Haoli; Peng Yong

2010-01-01

Using density functional theory and nonequilibrium Green's function (NEGF) formalism, we have theoretically investigated the binding of organic donor, acceptor and metal atoms on graphene sheets, and revealed the effects of the different noncovalent functionalizations on the electronic structure and transport properties of graphene. The adsorptions of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and tetrathiafulvalene (TTF) induce hybridization between the molecular levels and the graphene valence bands, and transform the zero-gap semiconducting graphene into a metallic graphene. However, the current versus voltage (I-V) simulation indicates that the noncovalent modifications by organic molecules are not sufficient to significantly alter the transport property of the graphene for sensing applications. We found that the molecule/graphene interaction could be dramatically enhanced by introducing metal atoms to construct molecule/metal/graphene sandwich structures. A chemical sensor based on iron modified graphene shows a sensitivity two orders of magnitude higher than that of pristine graphene. The results of this work could help to design novel graphene-based sensing or switching devices.

Optical investigation of the valency of Pr in Y1-xPrxBa2Cu3O7-δ

International Nuclear Information System (INIS)

Kircher, J.; Cardona, M.; Gopalan, S.; Habermeier, H.; Fuchs, D.

1991-01-01

We have investigated the dependence of the visible-ultraviolet dielectric function of Y 1-x Pr x Ba 2 Cu 3 O 7 on the Pr content x using rotating analyzer ellipsometry. Based on recently published band-structure calculations, we believe that the valency of Pr can be deduced from the optical properties in this spectral region. Interband transitions should shift to higher energies for Pr 4+ and to lower energies for Pr 3+ when compared to the optical spectra of YBa 2 Cu 3 O 7 . In the case of tetravalent Pr ions, transitions into unoccupied Pr 5d levels should be observable. Since the experimental energies for interband transitions shift down with increasing x and no additional structure can be seen, we conclude that Pr is trivalent in Y 1-x Pr x Ba 2 Cu 3 O 7

Segregation of information about emotional arousal and valence in horse whinnies.

Science.gov (United States)

Briefer, Elodie F; Maigrot, Anne-Laure; Mandel, Roi; Freymond, Sabrina Briefer; Bachmann, Iris; Hillmann, Edna

2015-04-21

Studying vocal correlates of emotions is important to provide a better understanding of the evolution of emotion expression through cross-species comparisons. Emotions are composed of two main dimensions: emotional arousal (calm versus excited) and valence (negative versus positive). These two dimensions could be encoded in different vocal parameters (segregation of information) or in the same parameters, inducing a trade-off between cues indicating emotional arousal and valence. We investigated these two hypotheses in horses. We placed horses in five situations eliciting several arousal levels and positive as well as negative valence. Physiological and behavioral measures collected during the tests suggested the presence of different underlying emotions. First, using detailed vocal analyses, we discovered that all whinnies contained two fundamental frequencies ("F0" and "G0"), which were not harmonically related, suggesting biphonation. Second, we found that F0 and the energy spectrum encoded arousal, while G0 and whinny duration encoded valence. Our results show that cues to emotional arousal and valence are segregated in different, relatively independent parameters of horse whinnies. Most of the emotion-related changes to vocalizations that we observed are similar to those observed in humans and other species, suggesting that vocal expression of emotions has been conserved throughout evolution.

Valence-Specific Laterality Effects in Vocal Emotion: Interactions with Stimulus Type, Blocking and Sex

Science.gov (United States)

Schepman, Astrid; Rodway, Paul; Geddes, Pauline

2012-01-01

Valence-specific laterality effects have been frequently obtained in facial emotion perception but not in vocal emotion perception. We report a dichotic listening study further examining whether valence-specific laterality effects generalise to vocal emotions. Based on previous literature, we tested whether valence-specific laterality effects were…

The power of emotional valence-from cognitive to affective processes in reading.

Science.gov (United States)

Altmann, Ulrike; Bohrn, Isabel C; Lubrich, Oliver; Menninghaus, Winfried; Jacobs, Arthur M

2012-01-01

The comprehension of stories requires the reader to imagine the cognitive and affective states of the characters. The content of many stories is unpleasant, as they often deal with conflict, disturbance or crisis. Nevertheless, unpleasant stories can be liked and enjoyed. In this fMRI study, we used a parametric approach to examine (1) the capacity of increasing negative valence of story contents to activate the mentalizing network (cognitive and affective theory of mind, ToM), and (2) the neural substrate of liking negatively valenced narratives. A set of 80 short narratives was compiled, ranging from neutral to negative emotional valence. For each story mean rating values on valence and liking were obtained from a group of 32 participants in a prestudy, and later included as parametric regressors in the fMRI analysis. Another group of 24 participants passively read the narratives in a three Tesla MRI scanner. Results revealed a stronger engagement of affective ToM-related brain areas with increasingly negative story valence. Stories that were unpleasant, but simultaneously liked, engaged the medial prefrontal cortex (mPFC), which might reflect the moral exploration of the story content. Further analysis showed that the more the mPFC becomes engaged during the reading of negatively valenced stories, the more coactivation can be observed in other brain areas related to the neural processing of affective ToM and empathy.

Observation of Rydberg transitions from the inner valence shell of ethane

International Nuclear Information System (INIS)

Dillon, M.A.; Tanaka, H.; Spence, D.

1987-01-01

The electron impact spectrum of ethane has been examined in a region that includes ionization out of the inner valence shell. One diffuse structure and a progression of ten vibrational bands have been found in a 4 eV range below and to some degree overlapping the 2 A 2 /sub u/ ion threshold. Evidence indicates that the observed transitions belong to the symmetry forbidden Rydberg series (2a 2 /sub u/) 2 →(2a 2 /sub u/, npσ or npπ)

Modulation of motor-meaning congruity effects for valenced words

OpenAIRE

Brookshire, Geoffrey; Ivry, Richard; Casasanto, Daniel

2010-01-01

We investigated the extent to which emotionally valenced words automatically cue spatio-motor representations. Participants made speeded button presses, moving their hand upward or downward while viewing words with positive or negative valence. Only the color of the words was relevant to the response; on target trials, there was no requirement to read the words or process their meaning. In Experiment 1, upward responses were faster for positive words, and downward for negative words. This eff...

Electronic structure effects in liquid water studied by photoelectron spectroscopy and density functional theory

Energy Technology Data Exchange (ETDEWEB)

Nordlund, Dennis; Odelius, Michael; Bluhm, Hendrik; Ogasawara, Hirohito; Pettersson, Lars G.M.; Nilsson, Anders

2008-04-29

We present valence photoelectron emission spectra of liquid water in comparison with gas-phase water, ice close to the melting point, low temperature amorphous and crystalline ice. All aggregation states have major electronic structure changes relative to the free molecule, with rehybridization and development of bonding and anti-bonding states accompanying the hydrogen bond formation. Sensitivity to the local structural order, most prominent in the shape and splitting of the occupied 3a{sub 1} orbital, is understood from the electronic structure averaging over various geometrical structures, and reflects the local nature of the orbital interaction.

Influence of emotional valence and arousal on the spread of activation in memory.

Science.gov (United States)

Jhean-Larose, Sandra; Leveau, Nicolas; Denhière, Guy

2014-11-01

Controversy still persists on whether emotional valence and arousal influence cognitive activities. Our study sought to compare how these two factors foster the spread of activation within the semantic network. In a lexical decision task, prime words were varied depending on the valence (pleasant or unpleasant) or on the level of emotional arousal (high or low). Target words were carefully selected to avoid semantic priming effects, as well as to avoid arousing specific emotions (neutral). Three SOA durations (220, 420 and 720 ms) were applied across three independent groups. Results indicate that at 220 ms, the effect of arousal is significantly higher than the effect of valence in facilitating spreading activation while at 420 ms, the effect of valence is significantly higher than the effect of arousal in facilitating spreading activation. These findings suggest that affect is a sequential process involving the successive intervention of arousal and valence.

Dissociable neural effects of stimulus valence and preceding context during the inhibition of responses to emotional faces.

Science.gov (United States)

Schulz, Kurt P; Clerkin, Suzanne M; Halperin, Jeffrey M; Newcorn, Jeffrey H; Tang, Cheuk Y; Fan, Jin

2009-09-01

Socially appropriate behavior requires the concurrent inhibition of actions that are inappropriate in the context. This self-regulatory function requires an interaction of inhibitory and emotional processes that recruits brain regions beyond those engaged by either processes alone. In this study, we isolated brain activity associated with response inhibition and emotional processing in 24 healthy adults using event-related functional magnetic resonance imaging (fMRI) and a go/no-go task that independently manipulated the context preceding no-go trials (ie, number of go trials) and the valence (ie, happy, sad, and neutral) of the face stimuli used as trial cues. Parallel quadratic trends were seen in correct inhibitions on no-go trials preceded by increasing numbers of go trials and associated activation for correct no-go trials in inferior frontal gyrus pars opercularis, pars triangularis, and pars orbitalis, temporoparietal junction, superior parietal lobule, and temporal sensory association cortices. Conversely, the comparison of happy versus neutral faces and sad versus neutral faces revealed valence-dependent activation in the amygdala, anterior insula cortex, and posterior midcingulate cortex. Further, an interaction between inhibition and emotion was seen in valence-dependent variations in the quadratic trend in no-go activation in the right inferior frontal gyrus and left posterior insula cortex. These results suggest that the inhibition of response to emotional cues involves the interaction of partly dissociable limbic and frontoparietal networks that encode emotional cues and use these cues to exert inhibitory control over the motor, attention, and sensory functions needed to perform the task, respectively. 2008 Wiley-Liss, Inc.

Band width and multiple-angle valence-state mapping of diamond

International Nuclear Information System (INIS)

Jimenez, I.; Terminello, L.J.; Sutherland, D.G.J.

1997-01-01

The band width may be considered the single most important parameter characterizing the electronic structure of a solid. The ratio of band width and Coulomb repulsion determines how correlated or delocalized an electron system is. Some of the most interesting solids straddle the boundary between localized and delocalized, e.g. the high-temperature superconductors. The bulk of the band calculations available today is based on local density functional (DF) theory. Even though the Kohn-Sham eigenvalues from that theory do not represent the outcome of a band-mapping experiment, they are remarkably similar to the bands mapped via photoemission. Strictly speaking, one should use an excited state calculation that takes the solid's many-body screening response to the hole created in photoemission into account. Diamond is a useful prototype semiconductor because of its low atomic number and large band width, which has made it a long-time favorite for testing band theory. Yet, the two experimental values of the band width of diamond have error bars of ±1 eV and differ by 3.2 eV. To obtain an accurate valence band width for diamond, the authors use a band-mapping method that collects momentum distributions instead of the usual energy distributions. This method has undergone extensive experimental and theoretical tests in determining the band width of lithium fluoride. An efficient, imaging photoelectron spectrometer is coupled with a state-of-the-art undulator beam line at the Advanced Light Source to allow collection of a large number of data sets. Since it takes only a few seconds to take a picture of the photoelectrons emitted into a 84 degrees cone, the authors can use photon energies as high as 350 eV where the cross section for photoemission from the valence band is already quite low, but the emitted photoelectrons behave free-electron-like. This make its much easier to locate the origin of the inter-band transitions in momentum space

Band width and multiple-angle valence-state mapping of diamond

Energy Technology Data Exchange (ETDEWEB)

Jimenez, I.; Terminello, L.J.; Sutherland, D.G.J. [Lawrence Berkeley National Lab., CA (United States)] [and others

1997-04-01

The band width may be considered the single most important parameter characterizing the electronic structure of a solid. The ratio of band width and Coulomb repulsion determines how correlated or delocalized an electron system is. Some of the most interesting solids straddle the boundary between localized and delocalized, e.g. the high-temperature superconductors. The bulk of the band calculations available today is based on local density functional (DF) theory. Even though the Kohn-Sham eigenvalues from that theory do not represent the outcome of a band-mapping experiment, they are remarkably similar to the bands mapped via photoemission. Strictly speaking, one should use an excited state calculation that takes the solid`s many-body screening response to the hole created in photoemission into account. Diamond is a useful prototype semiconductor because of its low atomic number and large band width, which has made it a long-time favorite for testing band theory. Yet, the two experimental values of the band width of diamond have error bars of {+-}1 eV and differ by 3.2 eV. To obtain an accurate valence band width for diamond, the authors use a band-mapping method that collects momentum distributions instead of the usual energy distributions. This method has undergone extensive experimental and theoretical tests in determining the band width of lithium fluoride. An efficient, imaging photoelectron spectrometer is coupled with a state-of-the-art undulator beam line at the Advanced Light Source to allow collection of a large number of data sets. Since it takes only a few seconds to take a picture of the photoelectrons emitted into a 84{degrees} cone, the authors can use photon energies as high as 350 eV where the cross section for photoemission from the valence band is already quite low, but the emitted photoelectrons behave free-electron-like. This make its much easier to locate the origin of the inter-band transitions in momentum space.

Momentum distributions and ionization potentials for the valence orbitals of hydrogen fluoride and hydrogen chloride

International Nuclear Information System (INIS)

Brion, C.E.; Hood, S.T.; Suzuki, I.H.; Weigold, E.

1980-02-01

The binding energy spectra and momentum distributions for the valence orbitals of HF and HCl have been obtained using (e,2e) spectroscopy with symmetric kinematics at 1200eV and 400eV. For HCl the strength of the innermost valence orbital (4sigma) is found to be significantly split among several ion states in the range 25eV to 41eV. The corresponding orbital in HF (2sigma) is however not significantly split among ion states. The measured momentum distributions are compared with the results of several calculatons of at least double zeta quality as well as with a one particle Green's function calculation of the generalized overlap amplitude. Agreement in shape is quite good for the innermost orbitals, but for the π and outer sigma orbitals of HF the momentum distributions calculated directly from the molecular orbitals are significantly more extended in momentum space than the measured distributions. The Green's function calculations give momentum distributions in good agreement with the data and pole strengths for transitions in qualitative agreement with the observed cross sections

Age-related emotional bias in processing two emotionally valenced tasks.

Science.gov (United States)

Allen, Philip A; Lien, Mei-Ching; Jardin, Elliott

2017-01-01

Previous studies suggest that older adults process positive emotions more efficiently than negative emotions, whereas younger adults show the reverse effect. We examined whether this age-related difference in emotional bias still occurs when attention is engaged in two emotional tasks. We used a psychological refractory period paradigm and varied the emotional valence of Task 1 and Task 2. In both experiments, Task 1 was emotional face discrimination (happy vs. angry faces) and Task 2 was sound discrimination (laugh, punch, vs. cork pop in Experiment 1 and laugh vs. scream in Experiment 2). The backward emotional correspondence effect for positively and negatively valenced Task 2 on Task 1 was measured. In both experiments, younger adults showed a backward correspondence effect from a negatively valenced Task 2, suggesting parallel processing of negatively valenced stimuli. Older adults showed similar negativity bias in Experiment 2 with a more salient negative sound ("scream" relative to "punch"). These results are consistent with an arousal-bias competition model [Mather and Sutherland (Perspectives in Psychological Sciences 6:114-133, 2011)], suggesting that emotional arousal modulates top-down attentional control settings (emotional regulation) with age.

16O + 16O molecular structures of superdeformed states in S isotopes

Science.gov (United States)

Taniguchi, Y.

2017-06-01

Structures of excited states in S isotopes are investigated by using the antisymmetrized molecular dynamics and generator coordinate method (GCM). The GCM basis wave functions are calculated via energy variation with a constraint on the quadrupole deformation parameter β. By applying the GCM after parity and angular momentum projections, the coexistence of positive- and negative-parity superdeformed (SD) bands are predicted in 33-36S except for negative-parity states in 36S. The SD bands have structures of 16O + 16O + valence neutron(s) in molecular orbitals around the two 16O cores in a cluster picture. The configurations of the valence neutron(s) in the SD states are δ and/or π molecular orbitals.

Hadron structure functions

International Nuclear Information System (INIS)

Martin, F.

1981-03-01

The x dependence of hadron structure functions is investigated. If quarks can exist in very low mass states (10 MeV for d and u quarks) the pion structure function is predicted to behave like (1-x) and not (1-x) 2 in a x-region around 1. Relativistic and non-relativistic quark bound state pictures of hadrons are considered together with their relation with the Q 2 evolution of structure functions. Good agreement with data is in general obtained

Photon structure function

International Nuclear Information System (INIS)

Bardeen, W.A.

1980-11-01

Theoretical understanding of the photon structure function is reviewed. As an illustration of the pointlike component, the parton model is briefly discussed. However, the systematic study of the photon structure function is presented through the framework of the operator product expansion. Perturbative QCD is used as the theoretical basis for the calculation of leading contributions to the operator product expansion. The influence of higher order QCD effects on these results is discussed. Recent results for the polarized structure functions are discussed

Valence band structure of InAs(1-x)Bi(x) and InSb(1-x)Bi(x) alloy semiconductors calculated using valence band anticrossing model.

Science.gov (United States)

Samajdar, D P; Dhar, S

2014-01-01

The valence band anticrossing model has been used to calculate the heavy/light hole and spin-orbit split-off energies in InAs(1-x)Bi(x) and InSb(1-x)Bi(x) alloy systems. It is found that both the heavy/light hole, and spin-orbit split E + levels move upwards in energy with an increase in Bi content in the alloy, whereas the split E - energy for the holes shows a reverse trend. The model is also used to calculate the reduction of band gap energy with an increase in Bi mole fraction. The calculated values of band gap variation agree well with the available experimental data.

Photoion mass spectroscopy and valence photoionization of hypoxanthine, xanthine and caffeine

Energy Technology Data Exchange (ETDEWEB)

Feyer, Vitaliy, E-mail: vitaliy.feyer@elettra.trieste.it [Sincrotrone Trieste, in Area Science Park, I-34012 Basovizza (Trieste) (Italy); Plekan, Oksana [Sincrotrone Trieste, in Area Science Park, I-34012 Basovizza (Trieste) (Italy)] [Institute of Electron Physics, 21 Universitetska St., 88017 Uzhgorod (Ukraine); Richter, Robert [Sincrotrone Trieste, in Area Science Park, I-34012 Basovizza (Trieste) (Italy); Coreno, Marcello [CNR-IMIP, Area della Ricerca di Roma 1, CP10, I-00016 Monterotondo Scalo (Italy)] [CNR-Laboratorio Nazionale TASC-INFM, I-34012 Basovizza (Trieste) (Italy); Prince, Kevin C. [Sincrotrone Trieste, in Area Science Park, I-34012 Basovizza (Trieste) (Italy)] [CNR-Laboratorio Nazionale TASC-INFM, I-34012 Basovizza (Trieste) (Italy)

2009-03-30

Photoionization mass spectra of hypoxanthine, xanthine and caffeine were measured using the photoelectron-photoion coincidence technique and noble gas resonance radiation at energies from 8.4 to 21.2 eV for ionization. The fragmentation patterns for these compounds show that hydrogen cyanide is the main neutral loss species at higher photon energies, while photoionization below 16.67 eV led predominantly to the parent ion. The valence photoelectron spectra of this family of molecules were measured over an extended energy range, including the inner C, N and O 2s valence orbitals. The observed ion fragments were related to ionization of the valence orbitals.

On single nucleon wave functions in nuclei

International Nuclear Information System (INIS)

Talmi, Igal

2011-01-01

The strong and singular interaction between nucleons, makes the nuclear many body theory very complicated. Still, nuclei exhibit simple and regular features which are simply described by the shell model. Wave functions of individual nucleons may be considered just as model wave functions which bear little resemblance to the real ones. There is, however, experimental evidence for the reality of single nucleon wave functions. There is a simple method of constructing such wave functions for valence nucleons. It is shown that this method can be improved by considering the polarization of the core by the valence nucleon. This gives rise to some rearrangement energy which affects the single valence nucleon energy within the nucleus.

Insights into the Electronic Structure of Ozone and Sulfur Dioxide from Generalized Valence Bond Theory: Addition of Hydrogen Atoms.

Science.gov (United States)

Lindquist, Beth A; Takeshita, Tyler Y; Dunning, Thom H

2016-05-05

Ozone (O3) and sulfur dioxide (SO2) are valence isoelectronic species, yet their properties and reactivities differ dramatically. In particular, O3 is highly reactive, whereas SO2 is chemically relatively stable. In this paper, we investigate serial addition of hydrogen atoms to both the terminal atoms of O3 and SO2 and to the central atom of these species. It is well-known that the terminal atoms of O3 are much more amenable to bond formation than those of SO2. We show that the differences in the electronic structure of the π systems in the parent triatomic species account for the differences in the addition of hydrogen atoms to the terminal atoms of O3 and SO2. Further, we find that the π system in SO2, which is a recoupled pair bond dyad, facilitates the addition of hydrogen atoms to the sulfur atom, resulting in stable HSO2 and H2SO2 species.

Fluorescence properties of valence-controlled Eu2+ and Mn2+ ions in aluminosilicate glasses

International Nuclear Information System (INIS)

Van Tuyen, Ho; Nonaka, Takamasa; Yamanaka, Ken-ichi; Chau, Pham Minh; Quy Hai, Nguyen Thi; Quang, Vu Xuan; Nogami, Masayuki

2017-01-01

Controlling of valence states of metal ions doped in glasses has attracted considerable interest due to the possibility of looking toward optical applications. In this study, new Na 2 O-Al 2 O 3 -SiO 2 glasses were developed to dope Eu 2+ and Mn 2+ with well controlled valence states by heating in H 2 gas atmosphere, and the changes in the valence state of doped-ions and their fluorescence properties were investigated using visible and infrared optical absorption spectroscopies, X-ray absorption fine structure spectroscopy, and fluorescence spectroscopy. Among Eu 3+ , Mn 3+ and Mn 2+ ions incorporated in the as-prepared glasses, the Eu 3+ and Mn 3+ ions were reduced to Eu 2+ and Mn 2+ ions, respectively, by heating in H 2 gas and OH bonds were concurrently formed. The fluorescence spectra of glasses heated in H 2 exhibited broad emission bands at 450 and 630 nm wavelength, assigned to the Eu 2+ and Mn 2+ , respectively, ions, in which the fluorescence intensity at 450 nm was observed to decrease with increasing Mn 2+ ion content. The increased fluorescence intensities were analyzed as the energy transfer from Eu 2+ to Mn 2+ ions and the energy transfer efficiency was estimated with a concentration of Eu 2+ and Mn 2+ ions.

Multi-functional composite structures

Science.gov (United States)

Mulligan, Anthony C.; Halloran, John; Popovich, Dragan; Rigali, Mark J.; Sutaria, Manish P.; Vaidyanathan, K. Ranji; Fulcher, Michael L.; Knittel, Kenneth L.

2004-10-19

Fibrous monolith processing techniques to fabricate multifunctional structures capable of performing more than one discrete function such as structures capable of bearing structural loads and mechanical stresses in service and also capable of performing at least one additional non-structural function.

A role of valence particles number equal to 20

International Nuclear Information System (INIS)

Kumar, V.; Kumar, S.; Hasan, Z.; Kumar, D.; Pradeep; Koranga, B.S.; Kumar, S.; Negi, D.

2012-01-01

The importance of the N p N n parametrization was first demonstrated by Casten in connection with the role of the proton-neutron interaction in the growth of deformation away from shell closures, and there have subsequently been many developments in this theme. The symbols N p and N n are number of valence particles/holes of protons and neutrons, respectively (where nucleons are counted as holes beyond the middle of a major shell). The observables which reflect collective structure in the deformed mass region for even-even nuclei such as E(2 + ), R 4/2 ≡ E(4 + )/E(2 + ) and B(E2) have behaved smoothly with N p N n

The bidirectional congruency effect of brightness-valence metaphoric association in the Stroop-like and priming paradigms.

Science.gov (United States)

Huang, Yanli; Tse, Chi-Shing; Xie, Jiushu

2017-11-04

The conceptual metaphor theory (Lakoff & Johnson, 1980, 1999) postulates a unidirectional metaphoric association between abstract and concrete concepts: sensorimotor experience activated by concrete concepts facilitates the processing of abstract concepts, but not the other way around. However, this unidirectional view has been challenged by studies that reported a bidirectional metaphoric association. In three experiments, we tested the directionality of the brightness-valence metaphoric association, using Stroop-like paradigm, priming paradigm, and Stroop-like paradigm with a go/no-go manipulation. Both mean and vincentile analyses of reaction time data were performed. We showed that the directionality of brightness-valence metaphoric congruency effect could be modulated by the activation level of the brightness/valence information. Both brightness-to-valence and valence-to-brightness metaphoric congruency effects occurred in the priming paradigm, which could be attributed to the presentation of prime that pre-activated the brightness or valence information. However, in the Stroop-like paradigm the metaphoric congruency effect was only observed in the brightness-to-valence direction, but not in the valence-to-brightness direction. When the go/no-go manipulation was used to boost the activation of word meaning in the Stroop-like paradigm, the valence-to-brightness metaphoric congruency effect was observed. Vincentile analyses further revealed that valence-to-brightness metaphoric congruency effect approached significance in the Stroop-like paradigm when participants' reaction times were slower (at around 490ms). The implications of the current findings on the conceptual metaphor theory and embodied cognition are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Valence Band Structure of InAs1−xBix and InSb1−xBix Alloy Semiconductors Calculated Using Valence Band Anticrossing Model

Science.gov (United States)

Samajdar, D. P.; Dhar, S.

2014-01-01

The valence band anticrossing model has been used to calculate the heavy/light hole and spin-orbit split-off energies in InAs1−xBix and InSb1−xBix alloy systems. It is found that both the heavy/light hole, and spin-orbit split E + levels move upwards in energy with an increase in Bi content in the alloy, whereas the split E − energy for the holes shows a reverse trend. The model is also used to calculate the reduction of band gap energy with an increase in Bi mole fraction. The calculated values of band gap variation agree well with the available experimental data. PMID:24592181

Valence and inner proton hole states in 207Tl via the (d,3He) reaction at 108 MeV

International Nuclear Information System (INIS)

Langevin-Joliot, H.; Gerlic, E.; Guillot, J.; Van de Wiele, J.

1983-01-01

The excitation energy spectra of the residual nucleus 207 Tl have been investigated up to 14 MeV using the (d, 3 He) reaction at 108 MeV. New groups and high lying structures are first observed up to 8.3 MeV, in addition to the five known low lying levels. Beyond a minimum at 7.13 MeV, weaker structures are observed riding over an asymetric bump located around 9 MeV. DWBA analysis of angular distributions have allowed l attributions and the determination of valence and inner hole spectroscopic factors. It is found that the valence levels at 1.33 MeV, 1.67 MeV and 3.47 MeV exhaust respectively about 65%, 60% and 45% of the 1hsub(11/2), 2dsub(5/2) and 1gsub(7/2) sum rules. The missing strengths are found below 8.3 MeV. The 2dsub(5/2) and 1gsub(7/2) holes contribute mainly to some well concentrated groups, whereas the 1hsub(11/2) strength is distributed more smoothly. Small contributions of 1gsub(9/2) and 2p strengths are tentatively identified below 7.13 MeV. The highest lying energy region up to 14 MeV may approximately account for the 1gsub(9/2) and (1fsub(5/2)) total sum-rule and about 70% of the 2p strength. The 1gsub(9/2) strength gives the largest contribution to the asymetric bump around 9 MeV. The deduced experimental strength functions are compared with theoretical calculations

A model on valence state evaluation of TRU nuclides in reprocessing solutions

International Nuclear Information System (INIS)

Uchiyama, Gunzo; Fujine, Sachio; Yoshida, Zenko; Maeda, Mitsuru; Motoyama, Satoshi.

1998-02-01

A mathematical model was developed to evaluate the valence state of TRU nuclides in reprocessing process solutions. The model consists of mass balance equations, Nernst equations, reaction rate equations and electrically neutrality equations. The model is applicable for the valence state evaluation of TRU nuclides in both steady state and transient state conditions in redox equilibrium. The valence state which is difficult to measure under high radiation and multi component conditions is calculated by the model using experimentally measured data for the TRU nuclide concentrations, nitric acid and redox reagent concentrations, electrode potential and solution temperature. (author)

Approach and withdrawal tendencies during written word processing: effects of task, emotional valence and emotional arousal

OpenAIRE

Citron, Francesca Maria Marina; Abugaber, David; Herbert, Cornelia

2016-01-01

The affective dimensions of emotional valence and emotional arousal affect processing of verbal and pictorial stimuli. Traditional emotional theories assume a linear relationship between these dimensions, with valence determining the direction of a behaviour (approach vs. withdrawal) and arousal its intensity or strength. In contrast, according to the valence-arousal conflict theory, both dimensions are interactively related: positive valence and low arousal (PL) are associated with an implic...

Unpolarized Structure Functions

International Nuclear Information System (INIS)

Christy, M.E.; Melnitchouk, W.

2011-01-01

Over the past decade measurements of unpolarized structure functions with unprecedented precision have significantly advanced our knowledge of nucleon structure. These have for the first time allowed quantitative tests of the phenomenon of quark-hadron duality, and provided a deeper understanding of the transition from hadron to quark degrees of freedom in inclusive scattering. Dedicated Rosenbluth-separation experiments have yielded high-precision transverse and longitudinal structure functions in regions previously unexplored, and new techniques have enabled the first glimpses of the structure of the free neutron, without contamination from nuclear effects.

Changing the conversation: the influence of emotions on conversational valence and alcohol consumption.

Science.gov (United States)

Hendriks, Hanneke; van den Putte, Bas; de Bruijn, Gert-Jan

2014-10-01

Health campaign effects may be improved by taking interpersonal communication processes into account. The current study, which employed an experimental, pretest-posttest, randomized exposure design (N = 208), investigated whether the emotions induced by anti-alcohol messages influence conversational valence about alcohol and subsequent persuasion outcomes. The study produced three main findings. First, an increase in the emotion fear induced a negative conversational valence about alcohol. Second, fear was most strongly induced by a disgusting message, whereas a humorous appeal induced the least fear. Third, a negative conversational valence elicited healthier binge drinking attitudes, subjective norms, perceived behavioral control, intentions, and behaviors. Thus, health campaign planners and health researchers should pay special attention to the emotional characteristics of health messages and should focus on inducing a healthy conversational valence.

A Combined Theoretical and Experimental View on Valence and Conduction Band Densities of States of Lead Halide Perovskites

Science.gov (United States)

Kronik, Leeor; Endres, James; Egger, David A.; Kulbak, Michael; Kerner, Ross A.; Zhao, Lianfeng; Silver, Scott H.; Hodes, Gary; Rand, Barry P.; Cahen, David; Kahn, Antoine

We present results for the valence and conduction band density of states (DOS), measured via ultraviolet and inverse photoemission spectroscopies for three lead halide perovskites. Specifically, the DOS of MAPbI3, MAPbBr3, and CsPbBr3, grown on different substrates, are compared. Theoretical DOS, calculated via hybrid density functional theory and including spin-orbit coupling, are compared to experimental data. The agreement between experiment and theory, obtained after correcting the latter for quantitative discrepancies, leads to the identification of valence and conduction band spectral features. In particular, this comparison allows for precise determination of the energy position of the band edges, namely ionization energies and electron affinities of these materials. We find an unusually low DOS at the valence band maximum (VBM) of these systems, which confirms and generalizes previous findings of strong band dispersion and low DOS at the VBM of MAPbI3. This calls for special attention when using electron spectroscopy to determine the frontier electronic states of lead halide perovskites.

Spectroscopic determination of valence band parameters in InP

International Nuclear Information System (INIS)

Lewis, R.A.; Lough, B.C.C.

2003-01-01

Full text: The general form of the Hamiltonian for an electron or hole in a semiconductor has been given by Luttinger. The valence band is characterised by three parameters - γ 1 , γ 2 , γ 3 -now commonly known as the Luttinger parameters. Despite many investigations there is still considerable uncertainty regarding the Luttinger parameters of InP. The situation has been reviewed by Hackenberg et al. These authors themselves sought to determine the Luttinger parameters by hot-electron luminescence and discovered that many Luttinger parameter triplets were consistent with their data. We employ a spectroscopic approach to estimating valence-band parameters in InP. Calculations have been made for both the unperturbed energy levels and the energy levels in a magnetic field of acceptor impurities in semiconductors characterised by different Luttinger parameters. We compare our recent experimental data for the transitions associated with the Zn acceptor impurity in InP in magnetic fields up to 30 T to determine the most appropriate set of valence-band parameters for InP

Valence band structure and density of states effective mass model of biaxial tensile strained silicon based on k · p theory

International Nuclear Information System (INIS)

Kuang Qian-Wei; Liu Hong-Xia; Wang Shu-Long; Qin Shan-Shan; Wang Zhi-Lin

2011-01-01

After constructing a stress and strain model, the valence bands of in-plane biaxial tensile strained Si is calculated by k · p method. In the paper we calculate the accurate anisotropy valance bands and the splitting energy between light and heavy hole bands. The results show that the valance bands are highly distorted, and the anisotropy is more obvious. To obtain the density of states (DOS) effective mass, which is a very important parameter for device modeling, a DOS effective mass model of biaxial tensile strained Si is constructed based on the valance band calculation. This model can be directly used in the device model of metal—oxide semiconductor field effect transistor (MOSFET). It also a provides valuable reference for biaxial tensile strained silicon MOSFET design. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

Electronic structures of azafullerene C48N12

International Nuclear Information System (INIS)

Brena, Barbara; Luo Yi

2003-01-01

Two recently proposed low-energy azafullerene C 48 N 12 isomers have been theoretically characterized using x-ray spectroscopies. The x-ray photoelectron spectroscopy, the near-edge absorption fine structure, the x-ray emission spectroscopy, and the ultraviolet photoelectron spectroscopy for both isomers have been predicted at the gradient-corrected density functional theory level. These spectroscopies together give a comprehensive insight of the electronic structure on the core, valence, and unoccupied orbitals. They have also provided a convincing way for identifying the isomer structures

Conduction Mechanism of Valence Change Resistive Switching Memory: A Survey

Directory of Open Access Journals (Sweden)

Ee Wah Lim

2015-09-01

Full Text Available Resistive switching effect in transition metal oxide (TMO based material is often associated with the valence change mechanism (VCM. Typical modeling of valence change resistive switching memory consists of three closely related phenomena, i.e., conductive filament (CF geometry evolution, conduction mechanism and temperature dynamic evolution. It is widely agreed that the electrochemical reduction-oxidation (redox process and oxygen vacancies migration plays an essential role in the CF forming and rupture process. However, the conduction mechanism of resistive switching memory varies considerably depending on the material used in the dielectric layer and selection of electrodes. Among the popular observations are the Poole-Frenkel emission, Schottky emission, space-charge-limited conduction (SCLC, trap-assisted tunneling (TAT and hopping conduction. In this article, we will conduct a survey on several published valence change resistive switching memories with a particular interest in the I-V characteristic and the corresponding conduction mechanism.

A facilitative effect of negative affective valence on working memory.

Science.gov (United States)

Gotoh, Fumiko; Kikuchi, Tadashi; Olofsson, Ulrich

2010-06-01

Previous studies have shown that negatively valenced information impaired working memory performance due to an attention-capturing effect. The present study examined whether negative valence could also facilitate working memory. Affective words (negative, neutral, positive) were used as retro-cues in a working memory task that required participants to remember colors at different spatial locations on a computer screen. Following the cue, a target detection task was used to either shift attention to a different location or keep attention at the same location as the retro-cue. Finally, participants were required to discriminate the cued color from a set of distractors. It was found that negative cues yielded shorter response times (RTs) in the attention-shift condition and longer RTs in the attention-stay condition, compared with neutral and positive cues. The results suggest that negative affective valence may enhance working memory performance (RTs), provided that attention can be disengaged.

Transfer of chirality from adsorbed chiral molecules to the substrates highlighted by circular dichroism in angle-resolved valence photoelectron spectroscopy

DEFF Research Database (Denmark)

Contini, G.; Turchini, S.; Sanna, Simone

2012-01-01

Studies of self-assembled chiral molecules on achiral metallic surfaces have mostly focused on the determination of the geometry of adsorbates and their electronic structure. The aim of this paper is to provide direct information on the chirality character of the system and on the chirality...... transfer from molecules to substrate by means of circular dichroism in the angular distribution of valence photoelectrons for the extended domain of the chiral self-assembled molecular structure, formed by alaninol adsorbed on Cu(100). We show, by the dichroic behavior of a mixed molecule–copper valence...... state, that the presence of molecular chiral domains induces asymmetry in the interaction with the substrate and locally transfers the chiral character to the underlying metal atoms participating in the adsorption process; combined information related to the asymmetry of the initial electronic state...

Interface structure and electronic properties of SrTiO3 and YBa2Cu3O7-δ crystals and thin films

International Nuclear Information System (INIS)

Thiess, S.

2007-01-01

Two new extensions of the X-ray standing wave (XSW) technique, made possible by the intense highly collimated X-ray beams from undulators at the ESRF, are described in this thesis. First, the XSW method was applied in a structural study to solve the nucleation mechanism of the high temperature superconductor YBa 2 Cu 3 O 7-δ on the (001) surface of SrTiO 3 . Second, the valence electronic structures of SrTiO 3 and YBa 2 Cu 3 O 7-δ were investigated. Finally, recent developments in the field of photoelectron spectroscopy in the hard X-ray region are described. The X-ray standing wave method is used in combination with fluorescence, Auger or photoelectron spectroscopy and lends very high spatial resolution power to these analytical techniques. Previously, the XSW method has been used for structure determination of surfaces and interfaces. The currently available X-ray intensities permit extensions to the XSW technique. Two recently established applications, described in this thesis, are XSW real space imaging and XSW valence electronic structure analysis. XSW real space imaging was employed to analyse the atomic structure of 0.5 and 1.0 layers of YBa 2 Cu 3 O 7-δ deposited on SrTiO 3 (001). Three-dimensional images of the atomic distributions were reconstructed for each of the elements from experimentally determined Fourier components of the atomic distribution functions. The images confirmed the formation of a perovskite precursor phase prior to the formation of the YBa 2 Cu 3 O 7-δ phase during the growth of the first monolayer of the film. XSW valence electronic structure analysis applied to SrTiO 3 identified the valence band contributions arising from the strontium, titanium, and oxygen sites of the crystal lattice. Relations between the site-specific valence electronic structure and the lattice structure were established. The experimental results agree very well with predictions by state-of-the-art ab initio calculations. X-ray absorption cross sections for

A Definition of the Magnetic Transition Temperature Using Valence Bond Theory.

Science.gov (United States)

Jornet-Somoza, Joaquim; Deumal, Mercè; Borge, Juan; Robb, Michael A

2018-03-01

Macroscopic magnetic properties are analyzed using Valence Bond theory. Commonly the critical temperature T C for magnetic systems is associated with a maximum in the energy-based heat capacity C p (T). Here a more broadly applicable definition of the magnetic transition temperature T C is described using the spin moment expectation value (i.e., applying the spin exchange density operator) instead of energy. Namely, the magnetic capacity C s (T) reflects variation in the spin multiplicity as a function of temperature, which is shown to be related to ∂[χT(T)]/∂T. Magnetic capacity C s (T) depends on long-range spin interactions that are not relevant in the energy-based heat capacity C p (T). Differences between C s (T) and C p (T) are shown to be due to spin order/disorder within the crystal that can be monitored via a Valence Bond analysis of the corresponding magnetic wave function. Indeed the concept of the Boltzmann spin-alignment order is used to provide information about the spin correlation between magnetic units. As a final illustration, the critical temperature is derived from the magnetic capacity for several molecular magnets presenting different magnetic topologies that have been experimentally studied. A systematic shift between the transition temperatures associated with C s (T) and C p (T) is observed. It is demonstrated that this shift can be attributed to the loss of long-range spin correlation. This suggests that the magnetic capacity C s (T) can be used as a predictive tool for the magnetic topology and thus for the synthetic chemists.

Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent Structure Functions in the Valence Quark Region

International Nuclear Information System (INIS)

Xiaochao Zheng; Konrad Aniol; David Armstrong; Todd Averett; William Bertozzi; Sebastien Binet; Etienne Burtin; Emmanuel Busato; Cornel Butuceanu; John Calarco; Alexandre Camsonne; Gordon Cates; Zhengwei Chai; Jian-ping Chen; Seonho Choi; Eugene Chudakov; Francesco Cusanno; Raffaele De Leo; Alexandre Deur; Sonja Dieterich; Dipangkar Dutta; John Finn; Salvatore Frullani; Haiyan Gao; Juncai Gao; Franco Garibaldi; Shalev Gilad; Ronald Gilman; Javier Gomez; Jens-ole Hansen; Douglas Higinbotham; Wendy Hinton; Tanja Horn; Cornelis De Jager; Xiaodong Jiang; Lisa Kaufman; James Kelly; Wolfgang Korsch; Kevin Kramer; John Lerose; David Lhuillier; Nilanga Liyanage; Demetrius Margaziotis; Frederic Marie; Pete Markowitz; Kathy Mccormick; Zein-eddine Meziani; Robert Michaels; Bryan Moffit; Sirish Nanda; Damien Neyret; Sarah Phillips; Anthony Powell; Thierry Pussieux; Bodo Reitz; Julie Roche; Michael Roedelbronn; Guy Ron; Marat Rvachev; Arunava Saha; Nikolai Savvinov; Jaideep Singh; Simon Sirca; Karl Slifer; Patricia Solvignon; Paul Souder; Daniel Steiner; Steffen Strauch; Vincent Sulkosky; William Tobias; Guido Urciuoli; Antonin Vacheret; Bogdan Wojtsekhowski; Hong Xiang; Yuan Xiao; Feng Xiong; Bin Zhang; Lingyan Zhu; Xiaofeng Zhu; Piotr Zolnierczuk

2004-01-01

We report on measurements of the neutron spin asymmetries A 1,2 n and polarized structure functions g 1,2 n at three kinematics in the deep inelastic region, with x = 0.33, 0.47 and .60 and Q 2 = 2.7, 3.5 and 4.8 (GeV/c) 2 , respectively. These measurements were performed using a 5.7 GeV longitudinally-polarized electron beam and a polarized 3 He target. The results for A 1 n and g 1 n at x = 0.33 are consistent with previous world data and, at the two higher x points, have improved the precision of the world data by about an order of magnitude. The new A 1 n data show a zero crossing around x = 0.47 and the value at x = 0.60 is significantly positive. These results agree with a next-to-leading order QCD analysis of previous world data. The trend of data at high x agrees with constituent quark model predictions but disagrees with that from leading-order perturbative QCD (pQCD) assuming hadron helicity conservation. Results for A 2 n and g 2 n have a precision comparable to the best world data in this kinematic region. Combined with previous world data, the moment d 2 n was evaluated and the new result has improved the precision of this quantity by about a factor of two. When combined with the world proton data, polarized quark distribution functions were extracted from the new g 1 n /F 1 n values based on the quark parton model. While results for Δu/u agree well with predictions from various models, results for Δd/d disagree with the leading-order pQCD prediction when hadron helicity conservation is imposed

The power of emotional valence – From cognitive to affective processes in reading

Directory of Open Access Journals (Sweden)

Ulrike eAltmann

2012-06-01

Full Text Available The comprehension of stories requires the reader to imagine the cognitive and affective states of the characters. The content of many stories is unpleasant, as they often deal with conflict, disturbance or crisis. Nevertheless, unpleasant stories can be liked and enjoyed. In this fMRI study, we used a parametric approach to examine (1 the capacity of increasing negative valence of story contents to activate the mentalizing network (cognitive and affective theory of mind, ToM, and (2 the neural substrate of liking negatively valenced narratives. A set of 80 short narratives was compiled, ranging from neutral to negative emotional valence. For each story mean rating values on valence and liking were obtained from a group of 32 participants in a prestudy, and later included as parametric regressors in the fMRI analysis. Another group of 24 participants passively read the narratives in a 3 Tesla MRI scanner. Results revealed a stronger engagement of affective ToM-related brain areas with increasingly negative story valence. Stories that were unpleasant, but simulatiously liked, selectively engaged the medial prefrontal cortex (mPFC, which might reflect the moral exploration of the story content. Further analysis showed that the more the mPFC becomes engaged during the reading of negatively valenced stories, the more coactivation can be observed in other brain areas related to the neural processing of affective ToM and empathy.

Chemical Bonding in Solids. On the Generalization of the Concept of Bond Order and Valence for Infinite Periodical Structures

Czech Academy of Sciences Publication Activity Database

Ponec, Robert

2005-01-01

Roč. 114, 1-3 (2005), s. 208-212 ISSN 1432-881X R&D Projects: GA AV ČR(CZ) IAA4072403 Institutional research plan: CEZ:AV0Z4072921 Keywords : bonding in solids * bond order * valence Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.179, year: 2005

What is the Valence of Mn in Ga(1-x)Mn(x)N?

Science.gov (United States)

Nelson, Ryky; Berlijn, Tom; Moreno, Juana; Jarrell, Mark; Ku, Wei

2015-11-06

We investigate the current debate on the Mn valence in Ga(1-x)Mn(x)N, a diluted magnetic semiconductor (DMS) with a potentially high Curie temperature. From a first-principles Wannier-function analysis, we unambiguously find the Mn valence to be close to 2+ (d(5)), but in a mixed spin configuration with average magnetic moments of 4μ(B). By integrating out high-energy degrees of freedom differently, we further derive for the first time from first-principles two low-energy pictures that reflect the intrinsic dual nature of the doped holes in the DMS: (1) an effective d(4) picture ideal for local physics, and (2) an effective d(5) picture suitable for extended properties. In the latter, our results further reveal a few novel physical effects, and pave the way for future realistic studies of magnetism. Our study not only resolves one of the outstanding key controversies of the field, but also exemplifies the general need for multiple effective descriptions to account for the rich low-energy physics in many-body systems in general.

Contribution to the study of higher valency states of americium

International Nuclear Information System (INIS)

Langlet, Jean.

1976-01-01

Study of the chemistry of the higher valencies of americium in aqueous solutions and especially the autoreduction phenomenon. First a purification method of americium solutions is studied by precipitation, solvent extraction and ion exchange chromatography. Studies of higher valency states chemical properties are disturbed by the autoreduction phenomenon changing Am VI and Am V in Am III more stable. Stabilization of higher valency states, characterized by a steady concentration of Am VI in solution, can be done by complexation of Am VI and Am V ions or by a protecting effect of foreign ions. The original medium used has a complexing effect by SO 4 2- ions and a protecting effect by the system S 2 O 8 2- -Ag + consuming H 2 O 2 main reducing agent produced by water radiolysis. These effects are shown by the study of Am VI in acid and basic solutions. A mechanism of the stabilization effect is given [fr

Electron and Nucleon Localization Functions of Oganesson: Approaching the Thomas-Fermi Limit

Science.gov (United States)

Jerabek, Paul; Schuetrumpf, Bastian; Schwerdtfeger, Peter; Nazarewicz, Witold

2018-02-01

Fermion localization functions are used to discuss electronic and nucleonic shell structure effects in the superheavy element oganesson, the heaviest element discovered to date. Spin-orbit splitting in the 7 p electronic shell becomes so large (˜10 eV ) that Og is expected to show uniform-gas-like behavior in the valence region with a rather large dipole polarizability compared to the lighter rare gas elements. The nucleon localization in Og is also predicted to undergo a transition to the Thomas-Fermi gas behavior in the valence region. This effect, particularly strong for neutrons, is due to the high density of single-particle orbitals.

Effects of surface condition on the work function and valence-band position of ZnSnN2

Science.gov (United States)

Shing, Amanda M.; Tolstova, Yulia; Lewis, Nathan S.; Atwater, Harry A.

2017-12-01

ZnSnN2 is an emerging wide band gap earth-abundant semiconductor with potential applications in photonic devices such as solar cells, LEDs, and optical sensors. We report the characterization by ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy of reactively radio-frequency sputtered II-IV-nitride ZnSnN2 thin films. For samples transferred in high vacuum, the ZnSnN2 surface work function was 4.0 ± 0.1 eV below the vacuum level, with a valence-band onset of 1.2 ± 0.1 eV below the Fermi level. The resulting band diagram indicates that the degenerate bulk Fermi level position in ZnSnN2 shifts to mid-gap at the surface due to band bending that results from equilibration with delocalized surface states within the gap. Brief (< 10 s) exposures to air, a nitrogen-plasma treatment, or argon-ion sputtering caused significant chemical changes at the surface, both in surface composition and interfacial energetics. The relative band positioning of the n-type semiconductor against standard redox potentials indicated that ZnSnN2 has an appropriate energy band alignment for use as a photoanode to effect the oxygen-evolution reaction.

Evaluative conditioning induces changes in sound valence

Directory of Open Access Journals (Sweden)

Anna C. Bolders

2012-04-01

Full Text Available Evaluative Conditioning (EC has hardly been tested in the auditory domain, but it is a potentially valuable research tool. In Experiment 1 we investigated whether the affective evaluation of short environmental sounds can be changed using affective words as unconditioned stimuli (US. Congruence effects on an affective priming task (APT for conditioned sounds demonstrated successful EC. Subjective ratings for sounds paired with negative words changed accordingly. In Experiment 2 we investigated whether the acquired valence remains stable after repeated presentation of the conditioned sound without the US or whether extinction occurs. The acquired affective value remained present, albeit weaker, even after 40 extinction trials. These results warrant the use of EC to study processing of short environmental sounds with acquired valence, even if this requires repeated stimulus presentations. This paves the way for studying processing of affective environmental sounds while effectively controlling low level-stimulus properties.

Curly arrows meet electron density transfers in chemical reaction mechanisms: from electron localization function (ELF) analysis to valence-shell electron-pair repulsion (VSEPR) inspired interpretation.

Science.gov (United States)

Andrés, Juan; Berski, Sławomir; Silvi, Bernard

2016-07-07

Probing the electron density transfers during a chemical reaction can provide important insights, making possible to understand and control chemical reactions. This aim has required extensions of the relationships between the traditional chemical concepts and the quantum mechanical ones. The present work examines the detailed chemical insights that have been generated through 100 years of work worldwide on G. N. Lewis's ground breaking paper on The Atom and the Molecule (Lewis, G. N. The Atom and the Molecule, J. Am. Chem. Soc. 1916, 38, 762-785), with a focus on how the determination of reaction mechanisms can be reached applying the bonding evolution theory (BET), emphasizing how curly arrows meet electron density transfers in chemical reaction mechanisms and how the Lewis structure can be recovered. BET that combines the topological analysis of the electron localization function (ELF) and Thom's catastrophe theory (CT) provides a powerful tool providing insight into molecular mechanisms of chemical rearrangements. In agreement with physical laws and quantum theoretical insights, BET can be considered as an appropriate tool to tackle chemical reactivity with a wide range of possible applications. Likewise, the present approach retrieves the classical curly arrows used to describe the rearrangements of chemical bonds for a given reaction mechanism, providing detailed physical grounds for this type of representation. The ideas underlying the valence-shell-electron pair-repulsion (VSEPR) model applied to non-equilibrium geometries provide simple chemical explanations of density transfers. For a given geometry around a central atom, the arrangement of the electronic domain may comply or not with the VSEPR rules according with the valence shell population of the considered atom. A deformation yields arrangements which are either VSEPR defective (at least a domain is missing to match the VSEPR arrangement corresponding to the geometry of the ligands), VSEPR compliant

Age effects in emotional prospective memory: cue valence differentially affects the prospective and retrospective component.

Science.gov (United States)

Schnitzspahn, Katharina M; Horn, Sebastian S; Bayen, Ute J; Kliegel, Matthias

2012-06-01

While first studies suggested that emotional task material may enhance prospective memory performance in young and older adults, the extent and mechanisms of this effect are under debate. The authors explored possible differential effects of cue valence on the prospective and retrospective component of prospective memory in young and older adults. Forty-five young and 41 older adults performed a prospective memory task in which emotional valence of the prospective memory cue was manipulated (positive, negative, neutral). The multinomial model of event-based prospective memory was used to analyze effects of valence and age on the two prospective memory components separately. Results revealed an interaction indicating that age differences were smaller in both emotional valence conditions. For older adults positive cues improved the prospective component, while negative cues improved the retrospective component. No main effect of valence was found for younger adults on an overt accuracy measure, but model-based analyses showed that the retrospective component was enhanced in the positive compared with the negative cue condition. The study extends the literature in demonstrating that processes underlying emotional effects on prospective memory may differ depending on valence and age. PsycINFO Database Record (c) 2012 APA, all rights reserved

Intermediate-Valence Tautomerism in Decamethylytterbocene Complexes of Methyl-Substituted Bipyridines

Energy Technology Data Exchange (ETDEWEB)

Booth, Corwin H.; Kazhdan, Daniel; Werkema, Evan L.; Walter, Marc D.; Lukens, Wayne W.; Bauer, Eric D.; Hu, Yung-Jin; Maron, Laurent; Eisenstein, Odile; Head-Gordon, Martin; Andersen, Richard A.

2011-01-25

Multiconfigurational, intermediate valent ground states are established in several methyl-substituted bipyridine complexes of bispentamethylcyclopentadienylytterbium, Cp*{sub 2} Yb(Me{sub x}-bipy). In contrast to Cp*{sub 2} Yb(bipy) and other substituted-bipy complexes, the nature of both the ground state and the first excited state are altered by changing the position of the methyl or dimethyl substitutions on the bipyridine rings. In particular, certain substitutions result in multiconfigurational, intermediate valent open-shell singlet states in both the ground state and the first excited state. These conclusions are reached after consideration of single-crystal x-ray diffraction (XRD), the temperature dependence of x-ray absorption near-edge structure (XANES), extended x-ray absorption fine-structure (EXAFS), and magnetic susceptibility data, and are supported by CASSCF-MP2 calculations. These results place the various Cp*{sub 2}Yb(bipy) complexes in a new tautomeric class, that is, intermediate-valence tautomers.

Density Functional Theory Calculations Revealing Metal-like Band Structures for Ultrathin Ge {111} and {211} Surface Layers.

Science.gov (United States)

Tan, Chih-Shan; Huang, Michael Hsuan-Yi

2018-05-21

To find out if germanium should also possess facet-dependent electrical conductivity properties, surface state density functional theory (DFT) calculations were performed on 1-6 layers of Ge (100), (110), (111), and (211) planes. Tunable Ge (100) and (110) planes always present the same semiconducting band structure with a band gap of 0.67 eV expected of bulk germanium. In contrast, 1, 2, 4, and 5 layers of Ge (111) and (211) plane models show metal-like band structures with continuous density of states (DOS) throughout the entire band. For 3 and 6 layers of Ge (111) and (211) plane models, the normal semiconducting band structure was obtained. The plane layers with metal-like band structures also show Ge-Ge bond length deviations and bond distortions, as well as significantly different 4s and 4p frontier orbital electron count and their relative percentages integrated over the valence and conduction bands from those of the semiconducting state. These differences should contribute to strikingly dissimilar band structures. The calculation results suggest observation of facet-dependent electrical conductivity properties of germanium materials, and transistors made of germanium may also need to consider the facet effects with shrinking dimensions approaching 3 nm. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Electronic structure investigation of MoS2 and MoSe2 using angle-resolved photoemission spectroscopy and ab initio band structure studies.

Science.gov (United States)

Mahatha, S K; Patel, K D; Menon, Krishnakumar S R

2012-11-28

Angle-resolved photoemission spectroscopy (ARPES) and ab initio band structure calculations have been used to study the detailed valence band structure of molybdenite, MoS(2) and MoSe(2). The experimental band structure obtained from ARPES has been found to be in good agreement with the theoretical calculations performed using the linear augmented plane wave (LAPW) method. In going from MoS(2) to MoSe(2), the dispersion of the valence bands decreases along both k(parallel) and k(perpendicular), revealing the increased two-dimensional character which is attributed to the increasing interlayer distance or c/a ratio in these compounds. The width of the valence band and the band gap are also found to decrease, whereas the valence band maxima shift towards the higher binding energy from MoS(2) to MoSe(2).

Unifying Exchange Sensitivity in Transition-Metal Spin-State Ordering and Catalysis through Bond Valence Metrics.

Science.gov (United States)

Gani, Terry Z H; Kulik, Heather J

2017-11-14

Accurate predictions of spin-state ordering, reaction energetics, and barrier heights are critical for the computational discovery of open-shell transition-metal (TM) catalysts. Semilocal approximations in density functional theory, such as the generalized gradient approximation (GGA), suffer from delocalization error that causes them to overstabilize strongly bonded states. Descriptions of energetics and bonding are often improved by introducing a fraction of exact exchange (e.g., erroneous low-spin GGA ground states are instead correctly predicted as high-spin with a hybrid functional). The degree of spin-splitting sensitivity to exchange can be understood based on the chemical composition of the complex, but the effect of exchange on reaction energetics within a single spin state is less well-established. Across a number of model iron complexes, we observe strong exchange sensitivities of reaction barriers and energies that are of the same magnitude as those for spin splitting energies. We rationalize trends in both reaction and spin energetics by introducing a measure of delocalization, the bond valence of the metal-ligand bonds in each complex. The bond valence thus represents a simple-to-compute property that unifies understanding of exchange sensitivity for catalytic properties and spin-state ordering in TM complexes. Close agreement of the resulting per-metal-organic-bond sensitivity estimates, together with failure of alternative descriptors demonstrates the utility of the bond valence as a robust descriptor of how differences in metal-ligand delocalization produce differing relative energetics with exchange tuning. Our unified description explains the overall effect of exact exchange tuning on the paradigmatic two-state FeO + /CH 4 reaction that combines challenges of spin-state and reactivity predictions. This new descriptor-sensitivity relationship provides a path to quantifying how predictions in transition-metal complex screening are sensitive to the

Persistence of Mixed and Non-intermediate Valence in the High-Pressure Structure of Silver(I,III) Oxide, AgO: A Combined Raman, X-ray Diffraction (XRD), and Density Functional Theory (DFT) Study.

Science.gov (United States)

Grzelak, Adam; Gawraczyński, Jakub; Jaroń, Tomasz; Somayazulu, Maddury; Derzsi, Mariana; Struzhkin, Viktor; Grochala, Wojciech

2017-05-15

The X-ray diffraction data collected up to ca. 56 GPa and the Raman spectra measured up to 74.8 GPa for AgO, or Ag I Ag III O 2 , which is a prototypical mixed valence (disproportionated) oxide, indicate that two consecutive phase transitions occur: the first-order phase transition occurs between 16.1 GPa and 19.7 GPa, and a second-order phase transition occurs at ca. 40 GPa. All polymorphic forms host the square planar [Ag III O 4 ] units typical of low-spin Ag III . The disproportionated Imma form persists at least up to 74.8 GPa, as indicated by Raman spectra. Theoretical hybrid density functional theory (DFT) calculations show that the first-order transition is phonon-driven. AgO stubbornly remains disproportionated up to at least 100 GPa-in striking contrast to its copper analogue-and the fundamental band gap of AgO is ∼0.3 eV at this pressure and is weakly pressure-dependent. Metallization of AgO is yet to be achieved.

Individual differences in emotion-cognition interactions: Emotional valence interacts with serotonin transporter genotype to influence brain systems involved in emotional reactivity and cognitive control

Directory of Open Access Journals (Sweden)

Melanie eStollstorff

2013-07-01

Full Text Available The serotonin transporter gene (5-HTTLPR influences emotional reactivity and attentional bias towards or away from emotional stimuli and has been implicated in psychopathological states, such as depression and anxiety disorder. The short allele is associated with increased reactivity and attention towards negatively-valenced emotional information, whereas the long allele is associated with that towards positively-valenced emotional information. The neural basis for individual differences in the ability to exert cognitive control over these bottom-up biases in emotional reactivity and attention is unknown, an issue investigated in the present study. Two groups, homozygous 5-HTTLPR long allele carriers or homozygous short allele carriers, underwent functional magnetic resonance imaging (fMRI while completing an Emotional Stroop-like task that varied with regards to the congruency of task-relevant and task-irrelevant information and the emotional valence of the task-irrelevant information. Behaviorally, participants demonstrated the classic Stroop effect (slower responses for incongruent than congruent trials, which did not differ by 5-HTTLPR genotype. However, fMRI results revealed that genotype influenced the degree to which neural systems were engaged depending on the valence of the conflicting task-irrelevant information. While the Long group recruited prefrontal control regions and superior temporal sulcus during conflict when task-irrelevant information was positively-valenced, the "Short" group recruited these regions when task-irrelevant information was negatively-valenced. Thus, participants successfully engaged cognitive control to overcome conflict in an emotional context using similar neural circuitry, but the engagement of this circuitry depended on emotional valence and 5-HTTLPR status. These results suggest that the interplay between emotion and cognition is modulated, in part, by a genetic polymorphism that influences serotonin

Variable valence of praseodymium in rare-earth oxide solid solutions

International Nuclear Information System (INIS)

Kravchinskaya, M.V.; Merezhinskii, K.Y.; Tikhonov, P.A.

1986-01-01

Solid solutions of elevated praseodymium oxide content have interesting electrical properties, making them the basis for the manufacture of high-temperature electrically conducting materials. Establishment of the composition-structure-valence state relationships enables control of the material properties. The authors performed investigations using a thermogravimetric apparatus with an electronic microbalance of type EM-5-3M, and using x-ray phase analysis of powders (DRON-1 diffractometer, CuK /SUB alpha/ -radiation). The authors also studied the kinetics of praseodymium oxidation with a thermogravimetric apparatus under isothermal conditions. Evaluation of the results with the equation of Kolmogorov, Erofeev, and Avraam indicates that the process is limited by the chemical oxidation of praseodymium and not by diffusion

Approach and Withdrawal Tendencies during Written Word Processing: Effects of Task, Emotional Valence, and Emotional Arousal.

Science.gov (United States)

Citron, Francesca M M; Abugaber, David; Herbert, Cornelia

2015-01-01

The affective dimensions of emotional valence and emotional arousal affect processing of verbal and pictorial stimuli. Traditional emotional theories assume a linear relationship between these dimensions, with valence determining the direction of a behavior (approach vs. withdrawal) and arousal its intensity or strength. In contrast, according to the valence-arousal conflict theory, both dimensions are interactively related: positive valence and low arousal (PL) are associated with an implicit tendency to approach a stimulus, whereas negative valence and high arousal (NH) are associated with withdrawal. Hence, positive, high-arousal (PH) and negative, low-arousal (NL) stimuli elicit conflicting action tendencies. By extending previous research that used several tasks and methods, the present study investigated whether and how emotional valence and arousal affect subjective approach vs. withdrawal tendencies toward emotional words during two novel tasks. In Study 1, participants had to decide whether they would approach or withdraw from concepts expressed by written words. In Studies 2 and 3 participants had to respond to each word by pressing one of two keys labeled with an arrow pointing upward or downward. Across experiments, positive and negative words, high or low in arousal, were presented. In Study 1 (explicit task), in line with the valence-arousal conflict theory, PH and NL words were responded to more slowly than PL and NH words. In addition, participants decided to approach positive words more often than negative words. In Studies 2 and 3, participants responded faster to positive than negative words, irrespective of their level of arousal. Furthermore, positive words were significantly more often associated with "up" responses than negative words, thus supporting the existence of implicit associations between stimulus valence and response coding (positive is up and negative is down). Hence, in contexts in which participants' spontaneous responses are

Pressure and irradiation effects on transport properties of samarium compounds with instable valence

International Nuclear Information System (INIS)

Morillo, J.

1981-01-01

Electron transport properties in samarium compounds with instable valence are studied in this thesis: from SmS in its integer valence phases at common pressure to SmB 6 compound IV at common pressure through SmSsub(1-x)Psub(x) (x 6 is presented [fr

Molecular invariants: atomic group valence

International Nuclear Information System (INIS)

Mundim, K.C.; Giambiagi, M.; Giambiagi, M.S. de.

1988-01-01

Molecular invariants may be deduced in a very compact way through Grassman algebra. In this work, a generalized valence is defined for an atomic group; it reduces to the Known expressions for the case of an atom in a molecule. It is the same of the correlations between the fluctions of the atomic charges qc and qd (C belongs to the group and D does not) around their average values. Numerical results agree with chemical expectation. (author) [pt

Social Annotation Valence: The Impact on Online Informed Consent Beliefs and Behavior.

Science.gov (United States)

Balestra, Martina; Shaer, Orit; Okerlund, Johanna; Westendorf, Lauren; Ball, Madeleine; Nov, Oded

2016-07-20

Social media, mobile and wearable technology, and connected devices have significantly expanded the opportunities for conducting biomedical research online. Electronic consent to collecting such data, however, poses new challenges when contrasted to traditional consent processes. It reduces the participant-researcher dialogue but provides an opportunity for the consent deliberation process to move from solitary to social settings. In this research, we propose that social annotations, embedded in the consent form, can help prospective participants deliberate on the research and the organization behind it in ways that traditional consent forms cannot. Furthermore, we examine the role of the comments' valence on prospective participants' beliefs and behavior. This study focuses specifically on the influence of annotations' valence on participants' perceptions and behaviors surrounding online consent for biomedical research. We hope to shed light on how social annotation can be incorporated into digitally mediated consent forms responsibly and effectively. In this controlled between-subjects experiment, participants were presented with an online consent form for a personal genomics study that contained social annotations embedded in its margins. Individuals were randomly assigned to view the consent form with positive-, negative-, or mixed-valence comments beside the text of the consent form. We compared participants' perceptions of being informed and having understood the material, their trust in the organization seeking the consent, and their actual consent across conditions. We find that comment valence has a marginally significant main effect on participants' perception of being informed (F2=2.40, P=.07); specifically, participants in the positive condition (mean 4.17, SD 0.94) felt less informed than those in the mixed condition (mean 4.50, SD 0.69, P=.09). Comment valence also had a marginal main effect on the extent to which participants reported trusting the

Verbal instructions targeting valence alter negative conditional stimulus evaluations (but do not affect reinstatement rates).

Science.gov (United States)

Luck, Camilla C; Lipp, Ottmar V

2018-02-01

Negative conditional stimulus (CS) valence acquired during fear conditioning may enhance fear relapse and is difficult to remove as it extinguishes slowly and does not respond to the instruction that unconditional stimulus (US) presentations will cease. We examined whether instructions targeting CS valence would be more effective. In Experiment 1, an image of one person (CS+) was paired with an aversive US, while another (CS-) was presented alone. After acquisition, participants were given positive information about the CS+ poser and negative information about the CS- poser. Instructions reversed the pattern of differential CS valence present during acquisition and eliminated differential electrodermal responding. In Experiment 2, we compared positive and negative CS revaluation by providing positive/negative information about the CS+ and neutral information about CS-. After positive revaluation, differential valence was removed and differential electrodermal responding remained intact. After negative revaluation, differential valence was strengthened and differential electrodermal responding was eliminated. Unexpectedly, the instructions did not affect the reinstatement of differential electrodermal responding.

Double-valence-fluctuating molecules and superconductivity

International Nuclear Information System (INIS)

Hirsch, J.E.; Scalapino, D.J.

1985-01-01

We discuss the possibility of ''double-valence-fluctuating'' molecules, having two ground-state configurations differing by two electrons. We propose a possible realization of such a molecule, and experimental ways to look for it. We argue that a weakly coupled array of such molecules should give rise to a strong-coupling Shafroth-Blatt-Butler superconductor, with a high transition temperature

Photon structure function - theory

International Nuclear Information System (INIS)

Bardeen, W.A.

1984-12-01

The theoretical status of the photon structure function is reviewed. Particular attention is paid to the hadronic mixing problem and the ability of perturbative QCD to make definitive predictions for the photon structure function. 11 references

Nuclear correlations and structure functions

International Nuclear Information System (INIS)

Hu Guoju; Irvine, J.M.

1989-01-01

It is argued that the search for a mass number dependence of the nuclear structure function per nucleon is profitably directed to the region of Bjorken scaling variable x > 1. We show that in the convolution model of the nuclear structure function the nuclear momentum distribution and energy spectrum generated by cluster expansion techniques, here realised in the correlated basis function method, invoking tensor correlations and short-range density-dependent repulsions adequately describes the structure function for 12 C in the region x > 1. The results of structure functions for a number of light-, medium- and heavy-mass nuclei are presented. (author)

Structure-based inference of molecular functions of proteins of unknown function from Berkeley Structural Genomics Center

Energy Technology Data Exchange (ETDEWEB)

Kim, Sung-Hou; Shin, Dong Hae; Hou, Jingtong; Chandonia, John-Marc; Das, Debanu; Choi, In-Geol; Kim, Rosalind; Kim, Sung-Hou

2007-09-02

Advances in sequence genomics have resulted in an accumulation of a huge number of protein sequences derived from genome sequences. However, the functions of a large portion of them cannot be inferred based on the current methods of sequence homology detection to proteins of known functions. Three-dimensional structure can have an important impact in providing inference of molecular function (physical and chemical function) of a protein of unknown function. Structural genomics centers worldwide have been determining many 3-D structures of the proteins of unknown functions, and possible molecular functions of them have been inferred based on their structures. Combined with bioinformatics and enzymatic assay tools, the successful acceleration of the process of protein structure determination through high throughput pipelines enables the rapid functional annotation of a large fraction of hypothetical proteins. We present a brief summary of the process we used at the Berkeley Structural Genomics Center to infer molecular functions of proteins of unknown function.

Synthesis, Crystal Structure, and Electroconducting Properties of a 1D Mixed-Valence Cu(I–Cu(II Coordination Polymer with a Dicyclohexyl Dithiocarbamate Ligand

Directory of Open Access Journals (Sweden)

Kenji Nakatani

2015-04-01

Full Text Available A new mixed-valence Cu(I–Cu(II 1D coordination polymer, [CuI4CuIIBr4(Cy2dtc2]n, with an infinite chain structure is synthesized by the reaction of Cu(Cy2dtc2 (Cy2dtc− = dicyclohexyl dithiocarbamate, C13H22NS2 with CuBr·S(CH32. The as-synthesized polymer consists of mononuclear copper(II units of CuII(Cy2dtc2 and tetranuclear copper(I cluster units, CuI4Br4. In the cluster unit, all the CuI ions have distorted trigonal pyramidal coordination geometries, and the CuI–CuI or CuI–CuII distances between the nearest copper ions are shorter than the sum of van der Waals radii for Cu–Cu.

Understanding molecular structure from molecular mechanics.

Science.gov (United States)

Allinger, Norman L

2011-04-01

Molecular mechanics gives us a well known model of molecular structure. It is less widely recognized that valence bond theory gives us structures which offer a direct interpretation of molecular mechanics formulations and parameters. The electronic effects well-known in physical organic chemistry can be directly interpreted in terms of valence bond structures, and hence quantitatively calculated and understood. The basic theory is outlined in this paper, and examples of the effects, and their interpretation in illustrative examples is presented.

Dissociable modulation of overt visual attention in valence and arousal revealed by topology of scan path.

Directory of Open Access Journals (Sweden)

Jianguang Ni

Full Text Available Emotional stimuli have evolutionary significance for the survival of organisms; therefore, they are attention-grabbing and are processed preferentially. The neural underpinnings of two principle emotional dimensions in affective space, valence (degree of pleasantness and arousal (intensity of evoked emotion, have been shown to be dissociable in the olfactory, gustatory and memory systems. However, the separable roles of valence and arousal in scene perception are poorly understood. In this study, we asked how these two emotional dimensions modulate overt visual attention. Twenty-two healthy volunteers freely viewed images from the International Affective Picture System (IAPS that were graded for affective levels of valence and arousal (high, medium, and low. Subjects' heads were immobilized and eye movements were recorded by camera to track overt shifts of visual attention. Algebraic graph-based approaches were introduced to model scan paths as weighted undirected path graphs, generating global topology metrics that characterize the algebraic connectivity of scan paths. Our data suggest that human subjects show different scanning patterns to stimuli with different affective ratings. Valence salient stimuli (with neutral arousal elicited faster and larger shifts of attention, while arousal salient stimuli (with neutral valence elicited local scanning, dense attention allocation and deep processing. Furthermore, our model revealed that the modulatory effect of valence was linearly related to the valence level, whereas the relation between the modulatory effect and the level of arousal was nonlinear. Hence, visual attention seems to be modulated by mechanisms that are separate for valence and arousal.

Polarisation of valence and non-strange sea quarks in the nucleon from semi-inclusive spin asymmetries

CERN Document Server

AUTHOR|(CDS)2067425; Arvidson, A; Badelek, B; Ballintijn, M K; Bardin, G; Baum, G; Berglund, P; Betev, L; Bird, I G; Birsa, R; Björkholm, P; Bonner, B E; De Botton, N R; Bradamante, Franco; Bressan, A; Bültmann, S; Burtin, E; Cavata, C; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Deshpande, A A; Dhawan, S K; Dulya, C M; Dyring, A; Eichblatt, S; Faivre, Jean-Claude; Fasching, D; Feinstein, F; Fernández, C; Frois, Bernard; Garzón, J A; Gaussiran, T; Giorgi, M A; von Goeler, E; Gómez, A; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Gülmez, E; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Karev, A G; Ketel, T; Kessler, H J; Kishi, A; Kiselev, Yu F; Klostermann, L; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kyynäräinen, J; Lamanna, M; Layda, T; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; López-Ponte, S; Loewe, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Van Middelkoop, G; Miller, D; Mori, K; Moromisato, J H; Nagaitsev, A P; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Penzo, Aldo L; Pérez, C; Perrot-Kunne, F; Peshekhonov, V D; Piegaia, R; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Pussieux, T; Pyrlik, J; Reyhancan, I; Rijllart, A; Roberts, J B; Rock, S E; Rodríguez, M; Rondio, Ewa; Rosado, A; Dabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schüler, K P; Segel, R E; Seitz, R; Semertzidis, Y K; Sergeev, S; Sever, F; Shanahan, P; Sichtermann, E P; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Teichert, K M; Tessarotto, F; Velasco, M; Vogt, J; Voss, Rüdiger; Weinstein, R; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Zanetti, A M; Zhao, J; Torre, S Dalla

1996-01-01

We present a measurement of semi-inclusive spin asymmetries for positively and negatively charged hadrons from deep inelastic scattering of polarised muons on polarised protons and deuterons in the range 0.003valence quarks and for {\\it non-strange} sea quarks. We find that the first moments of the valence quark spin distributions are \\Delta u_v = 1.01 \\pm 0.19 \\pm 0.14 and \\Delta d_v = -0.57 \\pm 0.22 \\pm 0.11. The spin distribution function of {\\it non-strange} sea quarks is consistent with zero over the measured range of x and the first moment is \\Delta \\bar u = \\Delta \\bar d = -0.02 \\pm 0.09 \\pm 0.03.

Metal-ligand delocalization and spin density in the CuCl2 and [CuCl4](2-) molecules: Some insights from wave function theory.

Science.gov (United States)

Giner, Emmanuel; Angeli, Celestino

2015-09-28

The aim of this paper is to unravel the physical phenomena involved in the calculation of the spin density of the CuCl2 and [CuCl4](2-) systems using wave function methods. Various types of wave functions are used here, both variational and perturbative, to analyse the effects impacting the spin density. It is found that the spin density on the chlorine ligands strongly depends on the mixing between two types of valence bond structures. It is demonstrated that the main difficulties found in most of the previous studies based on wave function methods come from the fact that each valence bond structure requires a different set of molecular orbitals and that using a unique set of molecular orbitals in a variational procedure leads to the removal of one of them from the wave function. Starting from these results, a method to compute the spin density at a reasonable computational cost is proposed.

Characterization of the Valence and Conduction Band Levels of n = 1 2D Perovskites: A Combined Experimental and Theoretical Investigation

KAUST Repository

Silver, Scott

2018-02-13

This study presents a combined experimental and theoretical study of the electronic structure of two 2D metal halide perovskite films. Ultraviolet and inverse photoemission spectroscopies are performed on solution-processed thin films of the n = 1 layered perovskite butylammonium lead iodide and bromide, BA2PbI4 and BA2PbBr4, characterized by optical absorption and X-ray diffraction, to determine their valence and conduction band densities of states, transport gaps, and exciton binding energies. The electron spectroscopy results are compared with the densities of states determined by density functional theory calculations. The remarkable agreement between experiment and calculation enables a detailed identification and analysis of the organic and inorganic contributions to the valence and conduction bands of these two hybrid perovskites. The electron affinity and ionization energies are found to be 3.1 and 5.8 eV for BA2PbI4, and 3.1 and 6.5 eV for BA2PbBr4. The exciton binding energies are estimated to be 260 and 300 meV for the two materials, respectively. The 2D lead iodide and bromide perovskites exhibit significantly less band dispersion and a larger density of states at the band edges than the 3D analogs. The effects of using various organic ligands are also discussed.

Momentum distributions and binding energies for the valence orbitals of methanol

International Nuclear Information System (INIS)

Minchinton, A.; Brion, C.E.; Weigold, E.

1981-06-01

Methanol has been studied by binary (e,2e) coincidence spectroscopy at 1200 eV using symmetric non-coplanar geometry. The binding energy spectrum has been determined in the energy range up to 46eV at azimuthal angles of 0 deg. and 7 deg. Momentum distributions measured for the valence orbitals are compared with calculations using the wave functions (essentially double-zeta quality) reported by Snyder and Basch. Agreement is generally quite good except for the outermost orbitals and the 5a' orbital which all show somewhat larger low momentum components than predicted by the calculations. This is indicative of a more spatially extended orbital than is predicted

The effect of cerium valence states at cerium oxide nanoparticle surfaces on cell proliferation

KAUST Repository

Naganuma, Tamaki

2014-05-01

Understanding and controlling cell proliferation on biomaterial surfaces is critical for scaffold/artificial-niche design in tissue engineering. The mechanism by which underlying integrin ligates with functionalized biomaterials to induce cell proliferation is still not completely understood. In this study, poly-l-lactide (PL) scaffold surfaces were functionalized using layers of cerium oxide nanoparticles (CNPs), which have recently attracted attention for use in therapeutic application due to their catalytic ability of Ce4+ and Ce3+ sites. To isolate the influence of Ce valance states of CNPs on cell proliferation, human mesenchymal stem cells (hMSCs) and osteoblast-like cells (MG63) were cultured on the PL/CNP surfaces with dominant Ce4+ and Ce3+ regions. Despite cell type (hMSCs and MG63 cells), different surface features of Ce4+ and Ce3+ regions clearly promoted and inhibited cell spreading, migration and adhesion behavior, resulting in rapid and slow cell proliferation, respectively. Cell proliferation results of various modified CNPs with different surface charge and hydrophobicity/hydrophilicity, indicate that Ce valence states closely correlated with the specific cell morphologies and cell-material interactions that trigger cell proliferation. This finding suggests that the cell-material interactions, which influence cell proliferation, may be controlled by introduction of metal elements with different valence states onto the biomaterial surface. © 2014 Elsevier Ltd.

An electron diffraction and bond valence sum study of the space group symmetries and structures of the photocatalytic 1:1 ordered A2InNbO6 double perovskites (A=Ca2+, Sr2+, Ba2+)

International Nuclear Information System (INIS)

Ting, V.; Liu, Y.; Withers, R.L.; Krausz, E.

2004-01-01

A careful investigation has been carried out into the space group symmetries, structures and crystal chemistries of the 1:1 B-site ordered double perovskites A 2 InNbO 6 (A=Ca 2+ , Sr 2+ , Ba 2+ ) using a combination of bond valence sum calculations, powder XRD and electron diffraction. A recent investigation of these compounds by Yin et al. reported a random distribution of In 3+ and Nb 5+ ions onto the perovskite B-site positions of these compounds and hence Pm3-barm (a=a p , subscript p for parent perovskite sub-structure) space group symmetry for the A=Ba and Sr compounds and Pnma (a=a p +b p , b=-a p +b p , c=2c p ) space group symmetry for the A=Ca compound. A careful electron diffraction study, however, shows that both the A=Ca and Sr compounds occur at room temperature in P12 1 /n1 (a=a p +b p , b=-a p +b p , c=2c p ) perovskite-related superstructure phases while the A=Ba compound occurs in the Fm3-barm, a=2a p , elpasolite structure type. Bond valence sum calculations are used to explain why this should be so as well as to provide a useful first-order approximation to the structures of each of the compounds

Valence of Facial Cues Influences Sheep Learning in a Visual Discrimination Task

Directory of Open Access Journals (Sweden)

Lucille G. A. Bellegarde

2017-11-01

Full Text Available Sheep are one of the most studied farm species in terms of their ability to process information from faces, but little is known about their face-based emotion recognition abilities. We investigated (a whether sheep could use images of sheep faces taken in situation of varying valence as cues in a simultaneous discrimination task and (b whether the valence of the situation affects their learning performance. To accomplish this, we photographed faces of sheep in three situations inducing emotional states of neutral (ruminating in the home pen or negative valence (social isolation or aggressive interaction. Sheep (n = 35 first had to learn a discrimination task with colored cards. Animals that reached the learning criterion (n = 16 were then presented with pairs of images of the face of a single individual taken in the neutral situation and in one of the negative situations. Finally, sheep had to generalize what they had learned to new pairs of images of faces taken in the same situation, but of a different conspecific. All sheep that learned the discrimination task with colored cards reached the learning criterion with images of faces. Sheep that had to associate a negative image with a food reward learned faster than sheep that had to associate a neutral image with a reward. With the exception of sheep from the aggression-rewarded group, sheep generalized this discrimination to images of faces of different individuals. Our results suggest that sheep can perceive the emotional valence displayed on faces of conspecifics and that this valence affects learning processes.

Lattice QCD with mixed action - Borici-Creutz valence quark on staggered sea

Science.gov (United States)

Basak, Subhasish; Goswami, Jishnu; Chakrabarti, Dipankar

2018-03-01

Mixed action lattice QCD with Borici-Creutz valence quarks on staggered sea is investigated. The counter terms in Borici-Creutz action are fixed nonperturbatively to restore the broken symmetries. On symmetry restoration, the usual signatures of partial quenching / unitarity violation like negative scalar correlator are observed. The size of unitarity violation due to different discretization of valence and sea quark is determined by measuring Δmix.

On-Ball Doping of Fullerenes : The Electronic Structure of C59N Dimers from Experiment and Theory

NARCIS (Netherlands)

Pichler, Thomas; Knupfer, Martin; Golden, Mark S.; Haffner, Stefan; Friedlein, Rainer; Fink, Jörg; Andreoni, Wanda; Curioni, Alessandro; Keshavarz-K, Majid; Bellavia-Lund, Cheryl; Sastre, Angela; Hummelen, Jan-Cornelis; Wudl, Fred

1997-01-01

We present the first studies of the electronic structure of the heterofullerene (C59N)2 using electron energy-loss spectroscopy in transmission, photoemission spectroscopy, and density functional theory calculations. Both the C 1s excitation spectra and valence band photoemission show negligible

Size-dependent valence change in small Pr, Nd, and Sm clusters isolated in solid Ar

International Nuclear Information System (INIS)

Luebcke, M.; Sonntag, B.; Niemann, W.; Rabe, P.

1986-01-01

The L/sub III/ absorption thresholds of Pr, Nd, and Sm clusters isolated in solid Ar are marked by prominent white lines. The lines ascribed to divalent and trivalent rare-earth metals are well separated in energy. From the relative intensities of these lines an average valence of the rare-earth atoms in the cluster has been determined. For dimers and trimers the average valence is close to 2, the value for free atoms. For clusters consisting of more than 20 atoms the average valence approaches 3, the value for bulk metals. In between the valence changes abruptly, indicating the existence of a critical cluster size of approximately 5 atoms for Pr and Nd and of 13 atoms for Sm

Orbitofrontal cortex function and structure in depression.

Science.gov (United States)

Drevets, Wayne C

2007-12-01

The orbitofrontal cortex (OFC) has been implicated in the pathophysiology of major depression by evidence obtained using neuroimaging, neuropathologic, and lesion analysis techniques. The abnormalities revealed by these techniques show a regional specificity, and suggest that some OFC regions which appear cytoarchitectonically distinct also are functionally distinct with respect to mood regulation. For example, the severity of depression correlates inversely with physiological activity in parts of the posterior lateral and medial OFC, consistent with evidence that dysfunction of the OFC associated with cerebrovascular lesions increases the vulnerability for developing the major depressive syndrome. The posterior lateral and medial OFC function may also be impaired in individuals who develop primary mood disorders, as these patients show grey-matter volumetric reductions, histopathologic abnormalities, and altered hemodynamic responses to emotionally valenced stimuli, probabilistic reversal learning, and reward processing. In contrast, physiological activity in the anteromedial OFC situated in the ventromedial frontal polar cortex increases during the depressed versus the remitted phases of major depressive disorder to an extent that is positively correlated with the severity of depression. Effective antidepressant treatment is associated with a reduction in activity in this region. Taken together these data are compatible with evidence from studies in experimental animals indicating that some orbitofrontal and medial prefrontal cortex regions function to inhibit, while others function to enhance, emotional expression. Alterations in the functional balance between these regions and the circuits they form with anatomically related areas of the temporal lobe, striatum, thalamus, and brain stem thus may underlie the pathophysiology of mood disorders, such as major depression.

Understanding valence-shell electron-pair repulsion (VSEPR) theory using origami molecular models

International Nuclear Information System (INIS)

Saraswati, Teguh Endah; Saputro, Sulistyo; Ramli, Murni; Praseptiangga, Danar; Khasanah, Nurul; Marwati, Sri

2017-01-01

Valence-shell electron-pair repulsion (VSEPR) theory is conventionally used to predict molecular geometry. However, it is difficult to explore the full implications of this theory by simply drawing chemical structures. Here, we introduce origami modelling as a more accessible approach for exploration of the VSEPR theory. Our technique is simple, readily accessible and inexpensive compared with other sophisticated methods such as computer simulation or commercial three-dimensional modelling kits. This method can be implemented in chemistry education at both the high school and university levels. We discuss the example of a simple molecular structure prediction for ammonia (NH 3 ). Using the origami model, both molecular shape and the scientific justification can be visualized easily. This ‘hands-on’ approach to building molecules will help promote understanding of VSEPR theory. (paper)

Understanding valence-shell electron-pair repulsion (VSEPR) theory using origami molecular models

Science.gov (United States)

Endah Saraswati, Teguh; Saputro, Sulistyo; Ramli, Murni; Praseptiangga, Danar; Khasanah, Nurul; Marwati, Sri

2017-01-01

Valence-shell electron-pair repulsion (VSEPR) theory is conventionally used to predict molecular geometry. However, it is difficult to explore the full implications of this theory by simply drawing chemical structures. Here, we introduce origami modelling as a more accessible approach for exploration of the VSEPR theory. Our technique is simple, readily accessible and inexpensive compared with other sophisticated methods such as computer simulation or commercial three-dimensional modelling kits. This method can be implemented in chemistry education at both the high school and university levels. We discuss the example of a simple molecular structure prediction for ammonia (NH3). Using the origami model, both molecular shape and the scientific justification can be visualized easily. This ‘hands-on’ approach to building molecules will help promote understanding of VSEPR theory.

Functional materials discovery using energy-structure-function maps.

Science.gov (United States)

Pulido, Angeles; Chen, Linjiang; Kaczorowski, Tomasz; Holden, Daniel; Little, Marc A; Chong, Samantha Y; Slater, Benjamin J; McMahon, David P; Bonillo, Baltasar; Stackhouse, Chloe J; Stephenson, Andrew; Kane, Christopher M; Clowes, Rob; Hasell, Tom; Cooper, Andrew I; Day, Graeme M

2017-03-30

Molecular crystals cannot be designed in the same manner as macroscopic objects, because they do not assemble according to simple, intuitive rules. Their structures result from the balance of many weak interactions, rather than from the strong and predictable bonding patterns found in metal-organic frameworks and covalent organic frameworks. Hence, design strategies that assume a topology or other structural blueprint will often fail. Here we combine computational crystal structure prediction and property prediction to build energy-structure-function maps that describe the possible structures and properties that are available to a candidate molecule. Using these maps, we identify a highly porous solid, which has the lowest density reported for a molecular crystal so far. Both the structure of the crystal and its physical properties, such as methane storage capacity and guest-molecule selectivity, are predicted using the molecular structure as the only input. More generally, energy-structure-function maps could be used to guide the experimental discovery of materials with any target function that can be calculated from predicted crystal structures, such as electronic structure or mechanical properties.

Approach and withdrawal tendencies during written word processing: effects of task, emotional valence and emotional arousal

Directory of Open Access Journals (Sweden)

Francesca M. M. Citron

2016-01-01

Full Text Available The affective dimensions of emotional valence and emotional arousal affect processing of verbal and pictorial stimuli. Traditional emotional theories assume a linear relationship between these dimensions, with valence determining the direction of a behaviour (approach vs. withdrawal and arousal its intensity or strength. In contrast, according to the valence-arousal conflict theory, both dimensions are interactively related: positive valence and low arousal (PL are associated with an implicit tendency to approach a stimulus, whereas negative valence and high arousal (NH are associated with withdrawal. Hence, positive, high-arousal (PH and negative, low-arousal (NL stimuli elicit conflicting action tendencies. By extending previous research that used several tasks and methods, the present study investigated whether and how emotional valence and arousal affect subjective approach vs. withdrawal tendencies towards emotional words during two novel tasks. In Study 1, participants had to decide whether they would approach or withdraw from concepts expressed by written words. In Studies 2 and 3 participants had to respond to each word by pressing one of two keys labelled with an arrow pointing upward or downward. Across experiments, positive and negative words, high or low in arousal, were presented. In Study 1 (explicit task, in line with the valence-arousal conflict theory, PH and NL words were responded to more slowly than PL and NH words. In addition, participants decided to approach positive words more often than negative words. In Studies 2 and 3, participants responded faster to positive than negative words, irrespective of their level of arousal. Furthermore, positive words were significantly more often associated with up responses than negative words, thus supporting the existence of implicit associations between stimulus valence and response coding (positive is up and negative is down. Hence, in contexts in which participants’ spontaneous

fK /f{pi} in Full QCD with Domain Wall Valence Quarks

Energy Technology Data Exchange (ETDEWEB)

Silas Beane; Paulo Bedaque; Konstantinos Orginos; Martin Savage

2007-05-01

We compute the ratio of pseudoscalar decay constants f{sub K}/f{sub {pi}} using domain-wall valence quarks and rooted improved Kogut-Susskind sea quarks. By employing continuum chiral perturbation theory, we extract the Gasser-Leutwyler low-energy constant L{sub 5}, and extrapolate f{sub K}/f{sub {pi}} to the physical point. We find: f{sub K}/f{sub {pi}} = 1.218 {+-} 0.002{sub -0.024}{sup +0.011} where the first error is statistical and the second error is an estimate of the systematic due to chiral extrapolation and fitting procedures. This value agrees within the uncertainties with the determination by the MILC collaboration, calculated using Kogut-Susskind valence quarks, indicating that systematic errors arising from the choice of lattice valence quark are small.

The use of symmetrized valence and relative motion coordinates for crystal potentials

DEFF Research Database (Denmark)

McMurry, H. L.; Hansen, Flemming Yssing

1980-01-01

Symmetrized valence coordinates are linear combinations of conventional valence coordinates which display the symmetry of a set of atoms bound by the valence bonds. Relative motion coordinates are relative translations, or relative rotations, of two or more strongly bonded groups of atoms among...... which relatively weak forces act. They are useful for expressing interactions between molecules in molecular crystals and should be chosen, also, to reflect the symmetry of the interacting groups. Since coordinates defined by these procedures possess elements of symmetry in common with the bonding...... interaction constants coupling coordinates of unlike symmetry with regard to the crystal point group are necessarily zero. They may be small, also, for coordinates which belong to different representations of the local symmetry when this is not the same as for the crystal. Procedures are given for defining...

The influence of valence and arousal on reasoning: Affective priming in the semantic verification task

Directory of Open Access Journals (Sweden)

Orlić Ana

2014-01-01

Full Text Available The aim of the present study was to examine the effects of affective valence and arousal on the reasoning process. Reasoning was measured using a semantic verification task and the influence of valence and arousal was tracked using the affective priming paradigm. Primes were photographs varied on two dimensions - emotional valence (positive, neutral, negative and arousal (high, low. Forty-nine psychology students participated in the experiment. Results showed that reaction time needed for semantic verification was significantly faster for positive-high arousing in comparison to positive-low arousing condition and for neutral high arousing in comparison to neutral-low arousing condition, but there were no significant differences in negative low and high arousing conditions. Also, significant differences were found among all three valences in high arousing conditions and there were no such differences in low arousing conditions. These results reveal the importance of both arousal and valence in the research on the influence of emotions on the reasoning process. [Projekat Ministarstva nauke Republike Srbije, br. 179033

Neurons for hunger and thirst transmit a negative-valence teaching signal

Science.gov (United States)

Gong, Rong; Magnus, Christopher J.; Yu, Yang; Sternson, Scott M.

2015-01-01

Homeostasis is a biological principle for regulation of essential physiological parameters within a set range. Behavioural responses due to deviation from homeostasis are critical for survival, but motivational processes engaged by physiological need states are incompletely understood. We examined motivational characteristics and dynamics of two separate neuron populations that regulate energy and fluid homeostasis by using cell type-specific activity manipulations in mice. We found that starvation-sensitive AGRP neurons exhibit properties consistent with a negative-valence teaching signal. Mice avoided activation of AGRP neurons, indicating that AGRP neuron activity has negative valence. AGRP neuron inhibition conditioned preference for flavours and places. Correspondingly, deep-brain calcium imaging revealed that AGRP neuron activity rapidly reduced in response to food-related cues. Complementary experiments activating thirst-promoting neurons also conditioned avoidance. Therefore, these need-sensing neurons condition preference for environmental cues associated with nutrient or water ingestion, which is learned through reduction of negative-valence signals during restoration of homeostasis. PMID:25915020

The role of valence focus and appraisal overlap in emotion differentiation.

Science.gov (United States)

Erbas, Yasemin; Ceulemans, Eva; Koval, Peter; Kuppens, Peter

2015-06-01

Emotion differentiation refers to the level of specificity with which people distinguish between their emotional states and is considered to play an important role for psychological well-being. Yet, not much is known about what characterizes people high or low in emotion differentiation and what underlies these differences. In 2 studies involving experience sampling (Studies 1-2) and lab based (Study 2) methods, we investigated how emotion differentiation is related to individual differences in valence focus and the overlap in appraisal patterns between emotions. In line with expectations, results showed that high levels of both positive and negative emotion differentiation are related to lower levels of valence focus and lower levels of appraisal overlap between emotions. These findings suggest that individuals who are low in emotion differentiation mainly emphasize the valence aspect of emotions while individuals who are high in emotion differentiation make stronger distinctions between emotions in terms of their underlying appraisal profiles. (c) 2015 APA, all rights reserved).

Quadrupole effects in core and valence photoelectron emission from crystalline germanium measured via a spatially modulated x-ray interference field

International Nuclear Information System (INIS)

Nelson, E.J.; Woicik, J.C.; Pianetta, P.; Vartanyants, I.A.; Cooper, J.W.

2002-01-01

Near a crystal x-ray Bragg reflection, the incident and reflected x-ray beams that travel with opposite wave vectors create an x-ray standing-wave (XSW) interference field. The quadrupole (and higher order nondipole) contributions to the photoelectron emission matrix element differ for these two beams due to their different wave vectors. By monitoring the angle-resolved photoelectron yield as a function of photon energy near the (11-1) Bragg back-reflection condition of crystalline Ge, we measure the contribution of nondipole effects to Ge 3p, Ge 3d, and Ge valence-band (4s and 4p) XSW photoelectron emission. Significant changes due to nondipole emission are measured in both the apparent amplitude and phase of the Ge structure factor relative to the true Ge atomic distribution, and compared to theory

Yb valence state in Yb{sub 5}Rh{sub 4}Ge{sub 10}

Energy Technology Data Exchange (ETDEWEB)

Sato, Hitoshi; Arita, Masashi; Shimada, Kenya; Namatame, Hirofumi; Taniguchi, Masaki [Hiroshima Synchrotron Radiation Center, Hiroshima University, Higashi-Hiroshima (Japan); Utsumi, Yuki [Synchrotron SOLEIL, L' Orme des Merisiers, Gif-sur-Yvette (France); Katoh, Kenichi [Department of Applied Physics, National Defense Academy, Yokosuka (Japan); Mimura, Kojiro [Graduate School of Engineering, Osaka Prefecture University, Sakai (Japan); Ueda, Shigenori [Synchrotron X-ray Station at SPring-8, National Institute for Materials Science, Hyogo (Japan); Quantum Beam Unit, National Institute for Materials Science, Tsukuba (Japan); Yamaoka, Hitoshi [RIKEN SPring-8 Center, Hyogo (Japan); Rousuli, Awabaikeli [Graduate School of Science, Hiroshima University, Higashi-Hiroshima (Japan); Umeo, Kazunori [NBARD, Hiroshima University, Higashi-Hiroshima (Japan)

2017-06-15

Temperature- and pressure-dependent Yb valence state in Yb{sub 5}Rh{sub 4}Ge{sub 10} has been investigated by means of Yb 3d hard X-ray photoemission spectroscopy (HAXPES) and Yb L{sub 3} absorption spectroscopy (XAS). The mean Yb valence derived from the Yb 3d HAXPES is estimated to be ∝2.78 at 300 K and decreases to ∝2.74 at 20 K. On the other hand, the Yb valence deduced from the Yb L{sub 3} XAS at 300 K is almost constant with ∝2.81 in the pressure range between 9.2 and 34.7 GPa. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Structure function monitor

Science.gov (United States)

McGraw, John T [Placitas, NM; Zimmer, Peter C [Albuquerque, NM; Ackermann, Mark R [Albuquerque, NM

2012-01-24

Methods and apparatus for a structure function monitor provide for generation of parameters characterizing a refractive medium. In an embodiment, a structure function monitor acquires images of a pupil plane and an image plane and, from these images, retrieves the phase over an aperture, unwraps the retrieved phase, and analyzes the unwrapped retrieved phase. In an embodiment, analysis yields atmospheric parameters measured at spatial scales from zero to the diameter of a telescope used to collect light from a source.

Interpersonal Valence Dimensions as Discriminators of Communication Contexts: An Empirical Assessment of Dyadic Linkages.

Science.gov (United States)

Garrison, John P.; And Others

The capability of 14 interpersonal dimensions to predict dyadic communication contexts was investigated in this study. Friend, acquaintance, co-worker, and family contexts were examined. The interpersonal valence construct, based on a coactive or mutual-causal paradigm, encompasses traditional source-valence components (credibility, power,…

Iron valence in double-perovskite (Ba,Sr,Ca)2FeMoO6: isovalent substitution effect

International Nuclear Information System (INIS)

Yasukawa, Y.; Linden, J.; Chan, T.S.; Liu, R.S.; Yamauchi, H.; Karppinen, M.

2004-01-01

In the Fe-Mo based B-site ordered double-perovskite, A 2 FeMoO 6.0 , with iron in the mixed-valence II/III state, the valence value of Fe is not precisely fixed at 2.5 but may be fine-tuned by means of applying chemical pressure at the A-cation site. This is shown through a systematic 57 Fe Moessbauer spectroscopy study using a series of A 2 FeMoO 6.0 [A=(Ba,Sr) or (Sr,Ca)] samples with high degree of Fe/Mo order, the same stoichiometric oxygen content and also almost the same grain size. The isomer shift values and other hyperfine parameters obtained from the Moessbauer spectra confirm that Fe remains in the mixed-valence state within the whole range of A constituents. However, upon increasing the average cation size at the A site the precise valence of Fe is found to decrease such that within the A=(Ba,Sr) regime the valence of Fe is closer to II, while within the A=(Sr,Ca) regime it is closer to the actual mixed-valence II/III state. As the valence of Fe approaches II, the difference in charges between Fe and Mo increases, and parallel with this the degree of Fe/Mo order increases. Additionally, for the less-ordered samples an increased tendency of clustering of the antisite Fe atoms is deduced from the Moessbauer data

Deep inelastic scattering and light-cone wave functions

International Nuclear Information System (INIS)

Belyaev, V.M.; Johnson, M.B.

1996-01-01

In the framework of light-cone QCD rules, we study the valence quark distribution function q(x B ) of a pion for moderate x B . The sum rule with the leading twist-2 wave function gives q(x B ) = φ π (x B ). Twist-4 wave functions give about 30% for x B ∼0.5. It is shown that QCD sum rule predictions, with the asymptotic pion wave function, are in good agreement with experimental data. We found that a two-hump profile for the twist-2 wave function leads to a valence quark distribution function that contradicts experimental data

Exploring the formation and electronic structure properties of the g-C3N4 nanoribbon with density functional theory.

Science.gov (United States)

Wu, Hong-Zhang; Zhong, Qing-Hua; Bandaru, Sateesh; Liu, Jin; Lau, Woon Ming; Li, Li-Li; Wang, Zhenling

2018-04-18

The optical properties and condensation degree (structure) of polymeric g-C 3 N 4 depend strongly on the process temperature. For polymeric g-C 3 N 4 , its structure and condensation degree depend on the structure of molecular strand(s). Here, the formation and electronic structure properties of the g-C 3 N 4 nanoribbon are investigated by studying the polymerization and crystallinity of molecular strand(s) employing first-principle density functional theory. The calculations show that the width of the molecular strand has a significant effect on the electronic structure of polymerized and crystallized g-C 3 N 4 nanoribbons, a conclusion which would be indirect evidence that the electronic structure depends on the structure of g-C 3 N 4 . The edge shape also has a distinct effect on the electronic structure of the crystallized g-C 3 N 4 nanoribbon. Furthermore, the conductive band minimum and valence band maximum of the polymeric g-C 3 N 4 nanoribbon show a strong localization, which is in good agreement with the quasi-monomer characters. In addition, molecular strands prefer to grow along the planar direction on graphene. These results provide new insight on the properties of the g-C 3 N 4 nanoribbon and the relationship between the structure and properties of g-C 3 N 4 .

Ab initio study of the isomerism of (LiAB)2 salt dimers with 24 valence electrons (AB- = NO-, PO-, NS-, PS-)

International Nuclear Information System (INIS)

Charkin, O.P.; Klimenko, N.M.; MakKi, M.L.

2000-01-01

The nonempiric calculations of the potential energies surfaces in the vicinity of the key structures of the loose dimer molecules of the (LiNO) 2 , (LiPO) 2 , (LiNS) 2 and (LiPS) 2 lithium salts with 24 valence electrons are accomplished within the frames of the MP2/6-31G * //HF/6-31g * + ZPE(HF/6-31G * and MP4SDTQ/6-31G * //MP2/6-31G * + ZPE(MP2/6-31G * ) approximation. The equilibrium geometrical parameters, relative energies and isomer decay energies, frequencies and IR-intensities of normal vibrations are determined. The geometrical deformations and shifts of vibrational frequencies of the cis- and trans-dianions under the effect of cations by different ways of their coordination as well as tendencies of the molecular properties behaviour in various series of dimers (LiAB) 2 are analyzed. The results obtained are compared with the data of previous calculations of the LiAB salts monomeric molecules, the Li 2 AB + ions with 12 valence electrons and the (LiAB) 2 dimers with 20 valence electrons [ru

Taking account of valence and core electronic wavefunction orthogonality in the semiempirical molecular orbital calculations

International Nuclear Information System (INIS)

Ginejtite, V.L.; Balyavichyus, L.Z.

1979-01-01

Some shortcomings of the semiempirical method CNDO/1 (complete naglect of differential overlap) taking into account wave function orthogonalities of outer valence electrons to inner shells are being explained. To avoid these shortcomings the introduction of pseudopotential is recommended. Addition of the potential excludes overestimation of attraction among chemically unbounded atoms, corrects underestimation of the single, double and triple S-S coupling, gives reasons for some suppositions of the semiempirical methods, gives a truthful distribution of the electronic levels

Feedback Valence Affects Auditory Perceptual Learning Independently of Feedback Probability

Science.gov (United States)

Amitay, Sygal; Moore, David R.; Molloy, Katharine; Halliday, Lorna F.

2015-01-01

Previous studies have suggested that negative feedback is more effective in driving learning than positive feedback. We investigated the effect on learning of providing varying amounts of negative and positive feedback while listeners attempted to discriminate between three identical tones; an impossible task that nevertheless produces robust learning. Four feedback conditions were compared during training: 90% positive feedback or 10% negative feedback informed the participants that they were doing equally well, while 10% positive or 90% negative feedback informed them they were doing equally badly. In all conditions the feedback was random in relation to the listeners’ responses (because the task was to discriminate three identical tones), yet both the valence (negative vs. positive) and the probability of feedback (10% vs. 90%) affected learning. Feedback that informed listeners they were doing badly resulted in better post-training performance than feedback that informed them they were doing well, independent of valence. In addition, positive feedback during training resulted in better post-training performance than negative feedback, but only positive feedback indicating listeners were doing badly on the task resulted in learning. As we have previously speculated, feedback that better reflected the difficulty of the task was more effective in driving learning than feedback that suggested performance was better than it should have been given perceived task difficulty. But contrary to expectations, positive feedback was more effective than negative feedback in driving learning. Feedback thus had two separable effects on learning: feedback valence affected motivation on a subjectively difficult task, and learning occurred only when feedback probability reflected the subjective difficulty. To optimize learning, training programs need to take into consideration both feedback valence and probability. PMID:25946173

Overlap valence quarks on a twisted mass sea. A case study for mixed action lattice QCD

International Nuclear Information System (INIS)

Cichy, Krzysztof; Herdoiza, Gregorio; UAM/CSIC Univ. Autonoma de Madrid

2012-11-01

We discuss a Lattice QCD mixed action investigation employing Wilson maximally twisted mass sea and overlap valence fermions. Using four values of the lattice spacing, we demonstrate that the overlap Dirac operator assumes a point-like locality in the continuum limit. We also show that by adopting suitable matching conditions for the sea and valence theories a consistent continuum limit for the pion decay constant and light baryon masses can be obtained. Finally, we confront results for sea-valence mixed meson masses and the valence scalar correlator with corresponding expressions of chiral perturbation theory. This allows us to extract low energy constants of mixed action chiral perturbation which characterize the strength of unitarity violations in our mixed action setup.

Overlap valence quarks on a twisted mass sea. A case study for mixed action lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Cichy, Krzysztof [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Poznan Univ. (Poland). Faculty of Physics; Drach, Vincent; Jansen, Karl [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Garcia-Ramos, Elena [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC; Humboldt-Universitaet, Berlin (Germany); Herdoiza, Gregorio [UAM/CSIC Univ. Autonoma de Madrid (Spain). Dept. de Fisica Teorica; UAM/CSIC Univ. Autonoma de Madrid (Spain). Inst. de Fisica Teorica; Collaboration: European Twisted Mass Collaboration

2012-11-15

We discuss a Lattice QCD mixed action investigation employing Wilson maximally twisted mass sea and overlap valence fermions. Using four values of the lattice spacing, we demonstrate that the overlap Dirac operator assumes a point-like locality in the continuum limit. We also show that by adopting suitable matching conditions for the sea and valence theories a consistent continuum limit for the pion decay constant and light baryon masses can be obtained. Finally, we confront results for sea-valence mixed meson masses and the valence scalar correlator with corresponding expressions of chiral perturbation theory. This allows us to extract low energy constants of mixed action chiral perturbation which characterize the strength of unitarity violations in our mixed action setup.

Unusual structures of MgF5- superhalogen anion

Science.gov (United States)

Anusiewicz, Iwona; Skurski, Piotr

2007-05-01

The vertical electron detachment energies (VDE) of three MgF5- anions were calculated at the outer valence Green function level with the 6-311 + G(3df) basis sets. This species was found to form unusual geometrical structures each of which corresponds to an anionic state exhibiting superhalogen nature. The global minimum structure was described as a system in which two central magnesium atoms are linked via symmetrical triangle formed by three fluorine atoms. Extremely large electron binding energies of these anions (exceeding 8.5 eV in all cases) were predicted and discussed.

The valence and Rydberg states of difluoromethane: A combined experimental vacuum ultraviolet spectrum absorption and theoretical study by ab initio configuration interaction and density functional computations

Science.gov (United States)

Palmer, Michael H.; Vrønning Hoffmann, Søren; Jones, Nykola C.; Coreno, Marcello; de Simone, Monica; Grazioli, Cesare

2018-06-01

The vacuum ultraviolet (VUV) spectrum for CH2F2 from a new synchrotron study has been combined with earlier data and subjected to detailed scrutiny. The onset of absorption, band I and also band IV, is resolved into broad vibrational peaks, which contrast with the continuous absorption previously claimed. A new theoretical analysis, using a combination of time dependent density functional theory (TDDFT) calculations and complete active space self-consistent field, leads to a major new interpretation. Adiabatic excitation energies (AEEs) and vertical excitation energies, evaluated by these methods, are used to interpret the spectra in unprecedented detail using theoretical vibronic analysis. This includes both Franck-Condon (FC) and Herzberg-Teller (HT) effects on cold and hot bands. These results lead to the re-assignment of several known excited states and the identification of new ones. The lowest calculated AEE sequence for singlet states is 11B1 ˜ 11A2 expected; the onset of the 15.5 eV band shows a set of vibrational peaks, but the vibration frequency does not correspond to any of the photoelectron spectral (PES) structure and is clearly valence in nature. The routine use of PES footprints to detect Rydberg states in VUV spectra is shown to be inadequate. The combined effects of FC and HT in the VUV spectral bands lead to additional vibrations when compared with the PES.

Spin--orbit configuration-interaction study of valence and Rydberg states of LiBe

International Nuclear Information System (INIS)

Marino, M.M.; Ermler, W.C.; Kern, C.W.; Bondybey, V.E.

1992-01-01

Ab initio spin--orbit full configuration-interaction calculations in the context of relativistic effective core potentials are reported for the weakly bound metal dimer LiBe, a three-valence-electron system. The effects of basis set on the energies of valence and Rydberg states of the cluster are discussed, as are the effects of configuration space selection on the energy of the latter states. Results at the dissociative limit are compared to the experimental atomic spectra. Potential-energy curves and spectroscopic constants are presented for the ground state and fourteen excited states, which includes the Li and Be 2p valence states, the Li 3s, 3p, 3d, and 4s Rydberg states, as well as three low-lying states of the molecular cation

Not always a matter of context: direct effects of red on arousal but context-dependent moderations on valence

Directory of Open Access Journals (Sweden)

Vanessa L. Buechner

2016-09-01

Full Text Available The arousal theory of color proposes that red is associated with arousal. Research on the color-in-context theory, in turn, states that the context in which red is perceived influences its valence-related meaning and behavioral responses to it. This study faces and integrates these theories by examining the influence of red on both arousal and valence perceptions of test-relevant and neutral stimuli, rendering a color 2 (red vs. blue × context 2 (test vs. neutral between-subjects design. Participants rated different pictures regarding their arousal and valence component, respectively. In line with the assumptions of both theories, red increased arousal perceptions of stimuli irrespective of their valence but a context × color interaction was found for valence perceptions: for participants viewing test-relevant pictures, red increased their perceptions of negativity compared to neutral pictures. The present study shows that both theories are actually compatible when differentiating the arousal and valence component.

Fluorescence properties of valence-controlled Eu{sup 2+} and Mn{sup 2+} ions in aluminosilicate glasses

Energy Technology Data Exchange (ETDEWEB)

Van Tuyen, Ho [Duy Tan University, 3 Quang Trung, Hai Chau, Da Nang (Viet Nam); Nonaka, Takamasa; Yamanaka, Ken-ichi [Toyota Central R& D Labs., Inc., Nagakute, Aichi (Japan); Chau, Pham Minh; Quy Hai, Nguyen Thi; Quang, Vu Xuan [Duy Tan University, 3 Quang Trung, Hai Chau, Da Nang (Viet Nam); Nogami, Masayuki, E-mail: mnogami@mtj.biglobe.ne.jp [Toyota Physical and Chemical Research Institute, Nagakute, Aichi (Japan); Ton Duc Thang University, Ho Chi Minh City (Viet Nam); Duy Tan University, 3 Quang Trung, Hai Chau, Da Nang (Viet Nam)

2017-04-15

Controlling of valence states of metal ions doped in glasses has attracted considerable interest due to the possibility of looking toward optical applications. In this study, new Na{sub 2}O-Al{sub 2}O{sub 3}-SiO{sub 2} glasses were developed to dope Eu{sup 2+} and Mn{sup 2+} with well controlled valence states by heating in H{sub 2} gas atmosphere, and the changes in the valence state of doped-ions and their fluorescence properties were investigated using visible and infrared optical absorption spectroscopies, X-ray absorption fine structure spectroscopy, and fluorescence spectroscopy. Among Eu{sup 3+}, Mn{sup 3+} and Mn{sup 2+} ions incorporated in the as-prepared glasses, the Eu{sup 3+} and Mn{sup 3+} ions were reduced to Eu{sup 2+} and Mn{sup 2+} ions, respectively, by heating in H{sub 2} gas and OH bonds were concurrently formed. The fluorescence spectra of glasses heated in H{sub 2} exhibited broad emission bands at 450 and 630 nm wavelength, assigned to the Eu{sup 2+} and Mn{sup 2+}, respectively, ions, in which the fluorescence intensity at 450 nm was observed to decrease with increasing Mn{sup 2+} ion content. The increased fluorescence intensities were analyzed as the energy transfer from Eu{sup 2+} to Mn{sup 2+} ions and the energy transfer efficiency was estimated with a concentration of Eu{sup 2+}and Mn{sup 2+} ions.

Implicit and Explicit Associations with Erotic Stimuli in Sexually Functional and Dysfunctional Men.

Science.gov (United States)

van Lankveld, Jacques; Odekerken, Ingrid; Kok-Verhoeven, Lydia; van Hooren, Susan; de Vries, Peter; van den Hout, Anja; Verboon, Peter

2015-08-01

Although conceptual models of sexual functioning have suggested a major role for implicit cognitive processing in sexual functioning, this has thus far, only been investigated in women. The aim of this study was to investigate the role of implicit cognition in sexual functioning in men. Men with (N = 29) and without sexual dysfunction (N = 31) were compared. Participants performed two single-target implicit association tests (ST-IAT), measuring the implicit association of visual erotic stimuli with attributes representing, respectively, valence ('liking') and motivation ('wanting'). Participants also rated the erotic pictures that were shown in the ST-IAT on the dimensions of valence, attractiveness, and sexual excitement to assess their explicit associations with these erotic stimuli. Participants completed the International Index of Erectile Functioning for a continuous measure of sexual functioning. Unexpectedly, compared with sexually functional men, sexually dysfunctional men were found to show stronger implicit associations of erotic stimuli with positive valence than with negative valence. Level of sexual functioning, however, was not predicted by explicit nor implicit associations. Level of sexual distress was predicted by explicit valence ratings, with positive ratings predicting higher levels of sexual distress. Men with and without sexual dysfunction differed significantly with regard to implicit liking. Research recommendations and implications are discussed. © 2015 International Society for Sexual Medicine.

Metal-ligand delocalization and spin density in the CuCl{sub 2} and [CuCl{sub 4}]{sup 2−} molecules: Some insights from wave function theory

Energy Technology Data Exchange (ETDEWEB)

Giner, Emmanuel, E-mail: gnrmnl@unife.it; Angeli, Celestino, E-mail: anc@unife.it [Dipartimento di Scienze Chimiche e Famaceutiche, Universita di Ferrara, Via Fossato di Mortara 17, I-44121 Ferrara (Italy)

2015-09-28

The aim of this paper is to unravel the physical phenomena involved in the calculation of the spin density of the CuCl{sub 2} and [CuCl{sub 4}]{sup 2−} systems using wave function methods. Various types of wave functions are used here, both variational and perturbative, to analyse the effects impacting the spin density. It is found that the spin density on the chlorine ligands strongly depends on the mixing between two types of valence bond structures. It is demonstrated that the main difficulties found in most of the previous studies based on wave function methods come from the fact that each valence bond structure requires a different set of molecular orbitals and that using a unique set of molecular orbitals in a variational procedure leads to the removal of one of them from the wave function. Starting from these results, a method to compute the spin density at a reasonable computational cost is proposed.

The accuracy of molecular bond lengths computed by multireference electronic structure methods

International Nuclear Information System (INIS)

Shepard, Ron; Kedziora, Gary S.; Lischka, Hans; Shavitt, Isaiah; Mueller, Thomas; Szalay, Peter G.; Kallay, Mihaly; Seth, Michael

2008-01-01

We compare experimental R e values with computed R e values for 20 molecules using three multireference electronic structure methods, MCSCF, MR-SDCI, and MR-AQCC. Three correlation-consistent orbital basis sets are used, along with complete basis set extrapolations, for all of the molecules. These data complement those computed previously with single-reference methods. Several trends are observed. The SCF R e values tend to be shorter than the experimental values, and the MCSCF values tend to be longer than the experimental values. We attribute these trends to the ionic contamination of the SCF wave function and to the corresponding systematic distortion of the potential energy curve. For the individual bonds, the MR-SDCI R e values tend to be shorter than the MR-AQCC values, which in turn tend to be shorter than the MCSCF values. Compared to the previous single-reference results, the MCSCF values are roughly comparable to the MP4 and CCSD methods, which are more accurate than might be expected due to the fact that these MCSCF wave functions include no extra-valence electron correlation effects. This suggests that static valence correlation effects, such as near-degeneracies and the ability to dissociate correctly to neutral fragments, play an important role in determining the shape of the potential energy surface, even near equilibrium structures. The MR-SDCI and MR-AQCC methods predict R e values with an accuracy comparable to, or better than, the best single-reference methods (MP4, CCSD, and CCSD(T)), despite the fact that triple and higher excitations into the extra-valence orbital space are included in the single-reference methods but are absent in the multireference wave functions. The computed R e values using the multireference methods tend to be smooth and monotonic with basis set improvement. The molecular structures are optimized using analytic energy gradients, and the timings for these calculations show the practical advantage of using variational wave

The accuracy of molecular bond lengths computed by multireference electronic structure methods

Energy Technology Data Exchange (ETDEWEB)

Shepard, Ron [Chemical Sciences and Engineering Division, Argonne National Laboratory, Argonne, IL 60439 (United States)], E-mail: shepard@tcg.anl.gov; Kedziora, Gary S. [High Performance Technologies Inc., 2435 5th Street, WPAFB, OH 45433 (United States); Lischka, Hans [Institute for Theoretical Chemistry, University of Vienna, Waehringerstrasse 17, A-1090 Vienna (Austria); Shavitt, Isaiah [Department of Chemistry, University of Illinois, 600 S. Mathews Avenue, Urbana, IL 61801 (United States); Mueller, Thomas [Juelich Supercomputer Centre, Research Centre Juelich, D-52425 Juelich (Germany); Szalay, Peter G. [Laboratory for Theoretical Chemistry, Institute of Chemistry, Eoetvoes Lorand University, P.O. Box 32, H-1518 Budapest (Hungary); Kallay, Mihaly [Department of Physical Chemistry and Materials Science, Budapest University of Technology and Economics, P.O. Box 91, H-1521 Budapest (Hungary); Seth, Michael [Department of Chemistry, University of Calgary, 2500 University Drive, N.W., Calgary, Alberta, T2N 1N4 (Canada)

2008-06-16

We compare experimental R{sub e} values with computed R{sub e} values for 20 molecules using three multireference electronic structure methods, MCSCF, MR-SDCI, and MR-AQCC. Three correlation-consistent orbital basis sets are used, along with complete basis set extrapolations, for all of the molecules. These data complement those computed previously with single-reference methods. Several trends are observed. The SCF R{sub e} values tend to be shorter than the experimental values, and the MCSCF values tend to be longer than the experimental values. We attribute these trends to the ionic contamination of the SCF wave function and to the corresponding systematic distortion of the potential energy curve. For the individual bonds, the MR-SDCI R{sub e} values tend to be shorter than the MR-AQCC values, which in turn tend to be shorter than the MCSCF values. Compared to the previous single-reference results, the MCSCF values are roughly comparable to the MP4 and CCSD methods, which are more accurate than might be expected due to the fact that these MCSCF wave functions include no extra-valence electron correlation effects. This suggests that static valence correlation effects, such as near-degeneracies and the ability to dissociate correctly to neutral fragments, play an important role in determining the shape of the potential energy surface, even near equilibrium structures. The MR-SDCI and MR-AQCC methods predict R{sub e} values with an accuracy comparable to, or better than, the best single-reference methods (MP4, CCSD, and CCSD(T)), despite the fact that triple and higher excitations into the extra-valence orbital space are included in the single-reference methods but are absent in the multireference wave functions. The computed R{sub e} values using the multireference methods tend to be smooth and monotonic with basis set improvement. The molecular structures are optimized using analytic energy gradients, and the timings for these calculations show the practical

Open-Minded Midwifes, Literate Butchers, and Greedy Hooligans—The Independent Contributions of Stereotype Valence and Consistency on Evaluative Judgments

Science.gov (United States)

Schubert, Lisa; Körner, Anita; Lindau, Berit; Strack, Fritz; Topolinski, Sascha

2017-01-01

Do people evaluate an open-minded midwife less positively than a caring midwife? Both open-minded and caring are generally seen as positive attributes. However, consistency varies—the attribute caring is consistent with the midwife stereotype while open-minded is not. In general, both stimulus valence and consistency can influence evaluations. Six experiments investigated the respective influence of valence and consistency on evaluative judgments in the domain of stereotyping. In an impression formation paradigm, valence and consistency of stereotypic information about target persons were manipulated orthogonally and spontaneous evaluations of these target persons were measured. Valence reliably influenced evaluations. However, for strongly valenced stereotypes, no effect of consistency was observed. Parameters possibly preventing the occurrence of consistency effects were ruled out, specifically, valence of inconsistent attributes, processing priority of category information, and impression formation instructions. However, consistency had subtle effects on evaluative judgments if the information about a target person was not strongly valenced and experimental conditions were optimal. Concluding, in principle, both stereotype valence and consistency can play a role in evaluative judgments of stereotypic target persons. However, the more subtle influence of consistency does not seem to substantially influence evaluations of stereotyped target persons. Implications for fluency research and stereotype disconfirmation are discussed. PMID:29062289

Open-Minded Midwifes, Literate Butchers, and Greedy Hooligans-The Independent Contributions of Stereotype Valence and Consistency on Evaluative Judgments.

Science.gov (United States)

Schubert, Lisa; Körner, Anita; Lindau, Berit; Strack, Fritz; Topolinski, Sascha

2017-01-01

Do people evaluate an open-minded midwife less positively than a caring midwife? Both open-minded and caring are generally seen as positive attributes. However, consistency varies-the attribute caring is consistent with the midwife stereotype while open-minded is not. In general, both stimulus valence and consistency can influence evaluations. Six experiments investigated the respective influence of valence and consistency on evaluative judgments in the domain of stereotyping. In an impression formation paradigm, valence and consistency of stereotypic information about target persons were manipulated orthogonally and spontaneous evaluations of these target persons were measured. Valence reliably influenced evaluations. However, for strongly valenced stereotypes, no effect of consistency was observed. Parameters possibly preventing the occurrence of consistency effects were ruled out, specifically, valence of inconsistent attributes, processing priority of category information, and impression formation instructions. However, consistency had subtle effects on evaluative judgments if the information about a target person was not strongly valenced and experimental conditions were optimal. Concluding, in principle, both stereotype valence and consistency can play a role in evaluative judgments of stereotypic target persons. However, the more subtle influence of consistency does not seem to substantially influence evaluations of stereotyped target persons. Implications for fluency research and stereotype disconfirmation are discussed.

Open-Minded Midwifes, Literate Butchers, and Greedy Hooligans—The Independent Contributions of Stereotype Valence and Consistency on Evaluative Judgments

Directory of Open Access Journals (Sweden)

Lisa Schubert

2017-10-01

Full Text Available Do people evaluate an open-minded midwife less positively than a caring midwife? Both open-minded and caring are generally seen as positive attributes. However, consistency varies—the attribute caring is consistent with the midwife stereotype while open-minded is not. In general, both stimulus valence and consistency can influence evaluations. Six experiments investigated the respective influence of valence and consistency on evaluative judgments in the domain of stereotyping. In an impression formation paradigm, valence and consistency of stereotypic information about target persons were manipulated orthogonally and spontaneous evaluations of these target persons were measured. Valence reliably influenced evaluations. However, for strongly valenced stereotypes, no effect of consistency was observed. Parameters possibly preventing the occurrence of consistency effects were ruled out, specifically, valence of inconsistent attributes, processing priority of category information, and impression formation instructions. However, consistency had subtle effects on evaluative judgments if the information about a target person was not strongly valenced and experimental conditions were optimal. Concluding, in principle, both stereotype valence and consistency can play a role in evaluative judgments of stereotypic target persons. However, the more subtle influence of consistency does not seem to substantially influence evaluations of stereotyped target persons. Implications for fluency research and stereotype disconfirmation are discussed.

Valence of facial cues influences sheep learning in a visual discrimination task

OpenAIRE

Bellegarde, Lucille; Erhard, Hans; Weiss, A.; Boissy, Alain; Haskell, M.J.

2017-01-01

Sheep are one of the most studied farm species in terms of their ability to process information from faces, but little is known about their face-based emotion recognition abilities. We investigated (a) whether sheep could use images of sheep faces taken in situation of varying valence as cues in a simultaneous discrimination task and (b) whether the valence of the situation affects their learning performance. To accomplish this, we photographed faces of sheep in three situations inducing emot...

Valence of Facial Cues Influences Sheep Learning in a Visual Discrimination Task

OpenAIRE

Lucille G. A. Bellegarde; Lucille G. A. Bellegarde; Lucille G. A. Bellegarde; Hans W. Erhard; Alexander Weiss; Alain Boissy; Marie J. Haskell

2017-01-01

Sheep are one of the most studied farm species in terms of their ability to process information from faces, but little is known about their face-based emotion recognition abilities. We investigated (a) whether sheep could use images of sheep faces taken in situation of varying valence as cues in a simultaneous discrimination task and (b) whether the valence of the situation affects their learning performance. To accomplish this, we photographed faces of sheep in three situations inducing emot...

Functional Insights from Structural Genomics

Energy Technology Data Exchange (ETDEWEB)

Forouhar,F.; Kuzin, A.; Seetharaman, J.; Lee, I.; Zhou, W.; Abashidze, M.; Chen, Y.; Montelione, G.; Tong, L.; et al

2007-01-01

Structural genomics efforts have produced structural information, either directly or by modeling, for thousands of proteins over the past few years. While many of these proteins have known functions, a large percentage of them have not been characterized at the functional level. The structural information has provided valuable functional insights on some of these proteins, through careful structural analyses, serendipity, and structure-guided functional screening. Some of the success stories based on structures solved at the Northeast Structural Genomics Consortium (NESG) are reported here. These include a novel methyl salicylate esterase with important role in plant innate immunity, a novel RNA methyltransferase (H. influenzae yggJ (HI0303)), a novel spermidine/spermine N-acetyltransferase (B. subtilis PaiA), a novel methyltransferase or AdoMet binding protein (A. fulgidus AF{_}0241), an ATP:cob(I)alamin adenosyltransferase (B. subtilis YvqK), a novel carboxysome pore (E. coli EutN), a proline racemase homolog with a disrupted active site (B. melitensis BME11586), an FMN-dependent enzyme (S. pneumoniae SP{_}1951), and a 12-stranded {beta}-barrel with a novel fold (V. parahaemolyticus VPA1032).

Risk-taking in disorders of natural and drug rewards: neural correlates and effects of probability, valence, and magnitude.

Science.gov (United States)

Voon, Valerie; Morris, Laurel S; Irvine, Michael A; Ruck, Christian; Worbe, Yulia; Derbyshire, Katherine; Rankov, Vladan; Schreiber, Liana Rn; Odlaug, Brian L; Harrison, Neil A; Wood, Jonathan; Robbins, Trevor W; Bullmore, Edward T; Grant, Jon E

2015-03-01

Pathological behaviors toward drugs and food rewards have underlying commonalities. Risk-taking has a fourfold pattern varying as a function of probability and valence leading to the nonlinearity of probability weighting with overweighting of small probabilities and underweighting of large probabilities. Here we assess these influences on risk-taking in patients with pathological behaviors toward drug and food rewards and examine structural neural correlates of nonlinearity of probability weighting in healthy volunteers. In the anticipation of rewards, subjects with binge eating disorder show greater risk-taking, similar to substance-use disorders. Methamphetamine-dependent subjects had greater nonlinearity of probability weighting along with impaired subjective discrimination of probability and reward magnitude. Ex-smokers also had lower risk-taking to rewards compared with non-smokers. In the anticipation of losses, obesity without binge eating had a similar pattern to other substance-use disorders. Obese subjects with binge eating also have impaired discrimination of subjective value similar to that of the methamphetamine-dependent subjects. Nonlinearity of probability weighting was associated with lower gray matter volume in dorsolateral and ventromedial prefrontal cortex and orbitofrontal cortex in healthy volunteers. Our findings support a distinct subtype of binge eating disorder in obesity with similarities in risk-taking in the reward domain to substance use disorders. The results dovetail with the current approach of defining mechanistically based dimensional approaches rather than categorical approaches to psychiatric disorders. The relationship to risk probability and valence may underlie the propensity toward pathological behaviors toward different types of rewards.

White Matter Deterioration May Foreshadow Impairment of Emotional Valence Determination in Early-Stage Dementia of the Alzheimer Type.

Science.gov (United States)

Rajmohan, Ravi; Anderson, Ronald C; Fang, Dan; Meyer, Austin G; Laengvejkal, Pavis; Julayanont, Parunyou; Hannabas, Greg; Linton, Kitten; Culberson, John; Khan, Hafiz M R; De Toledo, John; Reddy, P Hemachandra; O'Boyle, Michael

2017-01-01

In Alzheimer Disease (AD), non-verbal skills often remain intact for far longer than verbally mediated processes. Four (1 female, 3 males) participants with early-stage Clinically Diagnosed Dementia of the Alzheimer Type (CDDAT) and eight neurotypicals (NTs; 4 females, 4 males) completed the emotional valence determination test (EVDT) while undergoing BOLD functional magnetic resonance imaging (fMRI). We expected CDDAT participants to perform just as well as NTs on the EVDT, and to display increased activity within the bilateral amygdala and right anterior cingulate cortex (r-ACC). We hypothesized that such activity would reflect an increased reliance on these structures to compensate for on-going neuronal loss in frontoparietal regions due to the disease. We used diffusion tensor imaging (DTI) to determine if white matter (WM) damage had occurred in frontoparietal regions as well. CDDAT participants had similar behavioral performance and no differences were observed in brain activity or connectivity patterns within the amygdalae or r-ACC. Decreased fractional anisotropy (FA) values were noted, however, for the bilateral superior longitudinal fasciculi and posterior cingulate cortex (PCC). We interpret these findings to suggest that emotional valence determination and non-verbal skill sets are largely intact at this stage of the disease, but signs foreshadowing future decline were revealed by possible WM deterioration. Understanding how non-verbal skill sets are altered, while remaining largely intact, offers new insights into how non-verbal communication may be more successfully implemented in the care of AD patients and highlights the potential role of DTI as a presymptomatic biomarker.

Wave function analysis of type-II self-assembled quantum dot structures using magneto-optics

International Nuclear Information System (INIS)

Godoy, Marcio Peron Franco de; Nakaema, Marcelo K.K.; Gomes, Paulo F.; Iikawa, Fernando; Brasil, Maria Jose S.P.; Bortoleto, Jose Roberto R.; Cotta, Monica A.; Ribeiro, Evaldo; Medeiros-Ribeiro, Gilberto; Marques, Gilmar E.; Bittencourt, A.C.R.

2004-01-01

Full text: Recently, self-assembled quantum dots have attracted considerable attention for their potential for device applications. Type II interface, in particular, present interesting properties due to the space separation of the carriers. One of the carriers is confined at the lower band gap layer and the other remains at the barrier layers and is only localized by the Coulomb attraction. An essential information for using type II quantum wells and quantum dots on technological applications is the localization of the carrier wave function, which is an experimentally difficult parameter to be measured. Some techniques have been proposed to map the wave functions in quantum dots such as magneto-tunneling spectroscopy and near- field scanning optical microscopy. These techniques involve however a very complex experimental apparatus and sample processing. The magneto-exciton transition can be used as an alternative tool to investigate the exciton wave function distribution, since this distribution has a strong influence on the diamagnetic shift and Zeeman splitting. In this work, we present magneto-optical studies of In P/GaAs type II self-assembled quantum dots, where the electron is strongly confined at the In P, while the hole is weakly localized at the GaAs barrier due to the Coulombic attraction from the electrons. This scenery is very distinct from type I systems. The weaker hole confinement should alter the valence band mixing resulting in a different valence band contribution on the Zeeman splitting as compared to type I systems. Based on the results of the magneto-exciton emission from the wetting layer and from the individual dots, we obtained interesting results concerning the wave function distribution in our system. We discuss the localization of the hole wave function along the growth direction based on the measured Zeeman splitting and the in-plane wave function distribution, based on the observed diamagnetic shift. A remarkable result is that the

Crystal and magnetic structures of CaCu3Fe4O12 and LaCu3Fe4O12: distinct charge transitions of unusual high valence Fe

International Nuclear Information System (INIS)

Shimakawa, Yuichi

2015-01-01

New 134-type perovskites, CaCu 3 Fe 4 O 12 (CCFO) and LaCu 3 Fe 4 O 12 (LCFO), were prepared by means of high-pressure synthesis. The compounds contain unusual high valence Fe 4+ in CCFO and Fe 3.75+ in LCFO at high temperatures. With decreasing temperature, the instabilities of the high valence states of Fe are relieved by distinct charge transitions, which are charge disproportionation (4Fe 4+   →  2Fe 3+   +  2Fe 5+ ) in CCFO and intermetallic charge transfer (3Cu 2+   +  4Fe 3.75+   →  3Cu 3+   +  4Fe 3+ ) in LCFO. Crystal structure analysis with synchrotron x-ray diffraction and magnetic structure analysis with neutron diffraction revealed the nature of the transitions. Although the two behaviors look completely different from each other in simple ionic models, they can both be explained by the localization of ligand holes, which are produced by the strong hybridization of low-lying Fe-d and oxygen p orbitals in the oxides. The ligand holes in the charge disproportionated CCFO are localized at the Fe–O sites alternately (4d 5 L  →  2d 5   +  2d 5 L 2 ) and the ligand holes in the charge transferred LCFO are localized at the Cu–O sites (3d 9   +  4d 5 L 0.75   →  3d 9 L  +  4d 5 ). (review)

Nature of the valence band states in Bi2(Ca, Sr, La)3Cu2O8

International Nuclear Information System (INIS)

Wells, B.O.; Lindberg, P.A.P.; Shen, Z.; Dessau, D.S.; Spicer, W.E.; Lindau, I.; Mitzi, D.B.; Kapitulnik, A.

1990-01-01

We have used photoemission spectroscopy to examine the symmetry of the occupied states of the valence band for the La doped superconductor Bi 2 (Ca, Sr, La) 3 Cu 2 O 8 . While the oxygen states near the bottom of the 7 eV wide valence band exhibit predominantly O 2p z symmetry, the states at the top of the valence band extending to the Fermi level are found to have primarily O 2p x and O 2p y character. We have also examined anomalous intensity enhancements in the valence band feature for photon energies near 18 eV. These enhancements, which occur at photon energies ranging from 15.8 to 18.0 eV for the different valence band features, are not consistent with either simple final state effects or direct O2s transitions to unoccupied O2p states

Looking behaviour and preference for artworks: the role of emotional valence and location.

Science.gov (United States)

Kreplin, Ute; Thoma, Volker; Rodway, Paul

2014-10-01

The position of an item influences its evaluation, with research consistently finding that items occupying central locations are preferred and have a higher subjective value. The current study investigated whether this centre-stage effect (CSE) is a result of bottom-up gaze allocation to the central item, and whether it is affected by item valence. Participants (n=50) were presented with three images of artistic paintings in a row and asked to choose the image they preferred. Eye movements were recorded for a subset of participants (n=22). On each trial the three artworks were either similar but different, or were identical and with positive valence, or were identical and with negative valence. The results showed a centre-stage effect, with artworks in the centre of the row preferred, but only when they were identical and of positive valence. Significantly greater gaze allocation to the central and left artwork was not mirrored by equivalent increases in preference choices. Regression analyses showed that when the artworks were positive and identical the participants' last fixation predicted preference for the central art-work, whereas the fixation duration predicted preference if the images were different. Overall the result showed that item valence, rather than level of gaze allocation, influences the CSE, which is incompatible with the bottom-up gaze explanation. We propose that the centre stage heuristic, which specifies that the best items are in the middle, is able to explain these findings and the centre-stage effect. Copyright © 2014 Elsevier B.V. All rights reserved.

Two Parallel Pathways Assign Opposing Odor Valences during Drosophila Memory Formation

Directory of Open Access Journals (Sweden)

Daisuke Yamazaki

2018-02-01

Full Text Available During olfactory associative learning in Drosophila, odors activate specific subsets of intrinsic mushroom body (MB neurons. Coincident exposure to either rewards or punishments is thought to activate extrinsic dopaminergic neurons, which modulate synaptic connections between odor-encoding MB neurons and MB output neurons to alter behaviors. However, here we identify two classes of intrinsic MB γ neurons based on cAMP response element (CRE-dependent expression, γCRE-p and γCRE-n, which encode aversive and appetitive valences. γCRE-p and γCRE-n neurons act antagonistically to maintain neutral valences for neutral odors. Activation or inhibition of either cell type upsets this balance, toggling odor preferences to either positive or negative values. The mushroom body output neurons, MBON-γ5β′2a/β′2mp and MBON-γ2α′1, mediate the actions of γCRE-p and γCRE-n neurons. Our data indicate that MB neurons encode valence information, as well as odor information, and this information is integrated through a process involving MBONs to regulate learning and memory.

Organ donation video messaging: differential appeal, emotional valence, and behavioral intention.

Science.gov (United States)

Rodrigue, J R; Fleishman, A; Vishnevsky, T; Fitzpatrick, S; Boger, M

2014-10-01

Video narratives increasingly are used to draw the public's attention to the need for more registered organ donors. We assessed the differential impact of donation messaging videos on appeal, emotional valence, and organ donation intentions in 781 non-registered adults. Participants watched six videos (four personal narratives, one informational video without personal narrative, and one unrelated to donation) with or without sound (subtitled), randomly sequenced to minimize order effects. We assessed appeal, emotional valence, readiness to register as organ donors, and donation information-seeking behavior. Compared to other video types, one featuring a pediatric transplant recipient (with or without sound) showed more favorable appeal (p emotional valence (p emotion (OR = 1.05, 95% CI = 1.03, 1.07, p < 0.001) were significant multivariable predictors of clicking through to the donation website. Brief, one-min videos can have a very dramatic and positive impact on willingness to consider donation and behavioral intentions to register as an organ donor. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Enhanced conflict-driven cognitive control by emotional arousal, not by valence.

Science.gov (United States)

Zeng, Qinghong; Qi, Senqing; Li, Miaoyun; Yao, Shuxia; Ding, Cody; Yang, Dong

2017-09-01

Emotion is widely agreed to have two dimensions, valence and arousal. Few studies have explored the effect of emotion on conflict adaptation by considering both of these, which could have dissociate influence. The present study aimed to fill the gap as to whether emotional valence and arousal would exert dissociable influence on conflict adaptation. In the experiments, we included positive, neutral, and negative conditions, with comparable arousal between positive and negative conditions. Both positive and negative conditions have higher arousal than neutral ones. In Experiment 1, by using a two-colour-word Flanker task, we found that conflict adaptation was enhanced in both positive and negative contexts compared to a neutral context. Furthermore, this effect still existed when controlling stimulus-response repetitions in Experiment 2, which used a four-colour-word Flanker task. The findings suggest emotional arousal enhances conflict adaptation, regardless of emotional valence. Thus, future studies should consider emotional arousal when studying the effect of emotion on conflict adaptation. Moreover, the unique role of the emotional context in conflict-driven cognitive control is emphasised.

Vection Modulates Emotional Valence of Autobiographical Episodic Memories

Science.gov (United States)

Seno, Takeharu; Kawabe, Takahiro; Ito, Hiroyuki; Sunaga, Shoji

2013-01-01

We examined whether illusory self-motion perception ("vection") induced by viewing upward and downward grating motion stimuli can alter the emotional valence of recollected autobiographical episodic memories. We found that participants recollected positive episodes more often while perceiving upward vection. However, when we tested a small moving…

Electronic structure and optical properties of Cs2HgI4: Experimental study and band-structure DFT calculations

Science.gov (United States)

Lavrentyev, A. A.; Gabrelian, B. V.; Vu, V. T.; Shkumat, P. N.; Myronchuk, G. L.; Khvyshchun, M.; Fedorchuk, A. O.; Parasyuk, O. V.; Khyzhun, O. Y.

2015-04-01

High-quality single crystal of cesium mercury tetraiodide, Cs2HgI4, has been synthesized by the vertical Bridgman-Stockbarger method and its crystal structure has been refined. In addition, electronic structure and optical properties of Cs2HgI4 have been studied. For the crystal under study, X-ray photoelectron core-level and valence-band spectra for pristine and Ar+-ion irradiated surfaces have been measured. The present X-ray photoelectron spectroscopy (XPS) results indicate that the Cs2HgI4 single crystal surface is very sensitive with respect to Ar+ ion-irradiation. In particular, Ar+ bombardment of the single crystal surface alters the elemental stoichiometry of the Cs2HgI4 surface. To elucidate peculiarities of the energy distribution of the electronic states within the valence-band and conduction-band regions of the Cs2HgI4 compound, we have performed first-principles band-structure calculations based on density functional theory (DFT) as incorporated in the WIEN2k package. Total and partial densities of states for Cs2HgI4 have been calculated. The DFT calculations reveal that the I p states make the major contributions in the upper portion of the valence band, while the Hg d, Cs p and I s states are the dominant contributors in its lower portion. Temperature dependence of the light absorption coefficient and specific electrical conductivity has been explored for Cs2HgI4 in the temperature range of 77-300 K. Main optical characteristics of the Cs2HgI4 compound have been elucidated by the first-principles calculations.

Spin dependent photon structure functions

International Nuclear Information System (INIS)

Manohar, A.V.; Massachusetts Inst. of Tech., Cambridge

1989-01-01

Spin dependent structure functions of the photon are studied using the operator product expansion. There are new twist-two photon and gluon operators which contribute. The structure functions g 1 and F 3 are calculable in QCD, but differ from their free quark values. The corrections to F 3 are suppressed by 1/log Q 2 . The calculation is an extension of the analysis of Witten for the spin averaged structure functions F 1 and F 2 . (orig.)

Band Structure Analysis of La0.7Sr0.3MnO3 Perovskite Manganite Using a Synchrotron

Directory of Open Access Journals (Sweden)

Hong-Sub Lee

2015-01-01

Full Text Available Oxide semiconductors and their application in next-generation devices have received a great deal of attention due to their various optical, electric, and magnetic properties. For various applications, an understanding of these properties and their mechanisms is also very important. Various characteristics of these oxides originate from the band structure. In this study, we introduce a band structure analysis technique using a soft X-ray energy source to study a La0.7Sr0.3MnO3 (LSMO oxide semiconductor. The band structure is formed by a valence band, conduction band, band gap, work function, and electron affinity. These can be determined from secondary electron cut-off, valence band spectrum, O 1s core electron, and O K-edge measurements using synchrotron radiation. A detailed analysis of the band structure of the LSMO perovskite manganite oxide semiconductor thin film was established using these techniques.

Calculations of nucleon structure functions

International Nuclear Information System (INIS)

Signal, A.I.

1990-01-01

We present a method of calculating deep inelastic nucleon structure functions using bag model wavefunctions. Our method uses the Peierls - Yoccoz projection to form translation invariant bag states. We obtain the correct support for the structure functions and satisfy the positivity requirements for quark and anti-quark distribution functions. (orig.)

Interface structure and electronic properties of SrTiO{sub 3} and YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} crystals and thin films

Energy Technology Data Exchange (ETDEWEB)

Thiess, S.

2007-07-01

Two new extensions of the X-ray standing wave (XSW) technique, made possible by the intense highly collimated X-ray beams from undulators at the ESRF, are described in this thesis. First, the XSW method was applied in a structural study to solve the nucleation mechanism of the high temperature superconductor YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} on the (001) surface of SrTiO{sub 3}. Second, the valence electronic structures of SrTiO{sub 3} and YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} were investigated. Finally, recent developments in the field of photoelectron spectroscopy in the hard X-ray region are described. The X-ray standing wave method is used in combination with fluorescence, Auger or photoelectron spectroscopy and lends very high spatial resolution power to these analytical techniques. Previously, the XSW method has been used for structure determination of surfaces and interfaces. The currently available X-ray intensities permit extensions to the XSW technique. Two recently established applications, described in this thesis, are XSW real space imaging and XSW valence electronic structure analysis. XSW real space imaging was employed to analyse the atomic structure of 0.5 and 1.0 layers of YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} deposited on SrTiO{sub 3}(001). Three-dimensional images of the atomic distributions were reconstructed for each of the elements from experimentally determined Fourier components of the atomic distribution functions. The images confirmed the formation of a perovskite precursor phase prior to the formation of the YBa{sub 2}Cu{sub 3}O{sub 7-{delta}} phase during the growth of the first monolayer of the film. XSW valence electronic structure analysis applied to SrTiO{sub 3} identified the valence band contributions arising from the strontium, titanium, and oxygen sites of the crystal lattice. Relations between the site-specific valence electronic structure and the lattice structure were established. The experimental results agree very well with

Name-valence and physical attractiveness in Facebook: their compensatory effects on friendship acceptance.

Science.gov (United States)

Greitemeyer, Tobias; Kunz, Irene

2013-01-01

Name-valence and physical attractiveness have been shown to be associated with how people respond toward others, in that people judge and behave more positively toward individuals with positive names and individuals who are physically attractive. The present research examined whether Facebook users are more likely to accept friendship requests from other Facebook users with positive (relative to negative) names and who are physically attractive (relative to being moderately attractive). In fact, both name-valence and physical attractiveness affected friendship acceptance. Moreover, results revealed that name-valence can be compensated by physical attractiveness (and vice versa). Acceptance rates of requests from users with positive names who are moderately attractive, as well as requests from users with negative names who are attractive did not significantly differ from those with positive names who are attractive.

A first-principles study of the electronic structure of the sulvanite compounds

Energy Technology Data Exchange (ETDEWEB)

Osorio-Guillen, J.M., E-mail: jorge.osorio@fisica.udea.edu.co [Instituto de Fisica, Universidad de Antioquia, Medellin A.A. 1226 (Colombia); Espinosa-Garcia, W.F. [Instituto de Fisica, Universidad de Antioquia, Medellin A.A. 1226 (Colombia)

2012-03-15

We have investigated by means of first-principles total energy calculations the electronic structure of the sulvanite compounds: Cu{sub 3}VS{sub 4}, Cu{sub 3}NbS{sub 4} and Cu{sub 3}TaS{sub 4}; the later is a possible candidate as a p-type transparent conductor with potential applications in solar cells and electrochromic devices. The calculated electronic structure shows that these compounds are indirect band gap semiconductors, with the valence band maximum located at the R-point and the conduction band minimum located at the X-point. The character of the valence band maximum is dominated by Cu d-states and the character of the conduction band minimum is due to the d-states of the group five elements. From the calculated charge density and electron localisation function we can conclude that the sulvanite compounds are polar covalent semiconductors.

Nucleon structure functions

International Nuclear Information System (INIS)

Virchaux, M.

1992-11-01

The present status of experimental measurements of the nucleon structure functions is reviewed. The results from nearly all deep inelastic experiments are in good mutual agreement. Principles of the analysis of these structure function data in the framework of QCD are described. The specific features of the perturbative QCD predictions are observed in the data. This provides quantitative tests of the validity of QCD as well as determinations of the various parton distributions in the nucleon and some of the most precise measurements of the strong coupling constant αs. The future of this field of experimental physics is sketched

Core-electron binding energies from self-consistent field molecular orbital theory using a mixture of all-electron real atoms and valence-electron model atoms

International Nuclear Information System (INIS)

Quinn, C.M.; Schwartz, M.E.

1981-01-01

The chemistry of large systems such as clusters may be readily investigated by valence-electron theories based on model potentials, but such an approach does not allow for the examination of core-electron binding energies which are commonly measured experimentally for such systems. Here we merge our previously developed Gaussian based valence-electron model potential theory with all-electron ab initio theory to allow for the calculation of core orbital binding energies when desired. For the atoms whose cores are to be examined, we use the real nuclear changes, all of the electrons, and the appropriate many-electron basis sets. For the rest of the system we use reduced nuclear charges, the Gaussian based model potentials, only the valence electrons, and appropriate valence-electron basis sets. Detailed results for neutral Al 2 are presented for the cases of all-electron, mixed real--model, and model--model SCF--MO calculations. Several different all-electron and valence electron calculations have been done to test the use of the model potential per se, as well as the effect of basis set choice. The results are in all cases in excellent agreement with one another. Based on these studies, a set of ''double-zeta'' valence and all-electron basis functions have been used for further SCF--MO studies on Al 3 , Al 4 , AlNO, and OAl 3 . For a variety of difference combinations of real and model atoms we find excellent agreement for relative total energies, orbital energies (both core and valence), and Mulliken atomic populations. Finally, direct core-hole-state ionic calculations are reported in detail for Al 2 and AlNO, and noted for Al 3 and Al 4 . Results for corresponding frozen-orbital energy differences, relaxed SCF--MO energy differences, and relaxation energies are in all cases in excellent agreement (never differing by more than 0.07 eV, usually by somewhat less). The study clearly demonstrates the accuracy of the mixed real--model theory

Chromatin Structure and Function

CERN Document Server

Wolffe, Alan P

1999-01-01

The Third Edition of Chromatin: Structure and Function brings the reader up-to-date with the remarkable progress in chromatin research over the past three years. It has been extensively rewritten to cover new material on chromatin remodeling, histone modification, nuclear compartmentalization, DNA methylation, and transcriptional co-activators and co-repressors. The book is written in a clear and concise fashion, with 60 new illustrations. Chromatin: Structure and Function provides the reader with a concise and coherent account of the nature, structure, and assembly of chromatin and its active

Personality modulates the effects of emotional arousal and valence on brain activation.

Science.gov (United States)

Kehoe, Elizabeth G; Toomey, John M; Balsters, Joshua H; Bokde, Arun L W

2012-10-01

The influence of personality on the neural correlates of emotional processing is still not well characterized. We investigated the relationship between extraversion and neuroticism and emotional perception using functional magnetic resonance imaging (fMRI) in a group of 23 young, healthy women. Using a parametric modulation approach, we examined how the blood oxygenation level dependent (BOLD) signal varied with the participants' ratings of arousal and valence, and whether levels of extraversion and neuroticism were related to these modulations. In particular, we wished to test Eysenck's biological theory of personality, which links high extraversion to lower levels of reticulothalamic-cortical arousal, and neuroticism to increased reactivity of the limbic system and stronger reactions to emotional arousal. Individuals high in neuroticism demonstrated reduced sustained activation in the orbitofrontal cortex (OFC) and attenuated valence processing in the right temporal lobe while viewing emotional images, but an increased BOLD response to emotional arousal in the right medial prefrontal cortex (mPFC). These results support Eysenck's theory, as well as our hypothesis that high levels of neuroticism are associated with attenuated reward processing. Extraversion was inversely related to arousal processing in the right cerebellum, but positively associated with arousal processing in the right insula, indicating that the relationship between extraversion and arousal is not as simple as that proposed by Eysenck.

Dissociable neural systems underwrite logical reasoning in the context of induced emotions with positive and negative valence.

Science.gov (United States)

Smith, Kathleen W; Vartanian, Oshin; Goel, Vinod

2014-01-01

How emotions influence syllogistic reasoning is not well understood. fMRI was employed to investigate the effects of induced positive or negative emotion on syllogistic reasoning. Specifically, on a trial-by-trial basis participants were exposed to a positive, negative, or neutral picture, immediately prior to engagement in a reasoning task. After viewing and rating the valence and intensity of each picture, participants indicated by keypress whether or not the conclusion of the syllogism followed logically from the premises. The content of all syllogisms was neutral, and the influence of belief-bias was controlled for in the study design. Emotion did not affect reasoning performance, although there was a trend in the expected direction based on accuracy rates for the positive (63%) and negative (64%) versus neutral (70%) condition. Nevertheless, exposure to positive and negative pictures led to dissociable patterns of neural activation during reasoning. Therefore, the neural basis of deductive reasoning differs as a function of the valence of the context.

Dissociable Neural Systems Underwrite Logical Reasoning in the Context of Induced Emotions with Positive and Negative Valence

Science.gov (United States)

Smith, Kathleen W.; Vartanian, Oshin; Goel, Vinod

2014-01-01

How emotions influence syllogistic reasoning is not well understood. fMRI was employed to investigate the effects of induced positive or negative emotion on syllogistic reasoning. Specifically, on a trial-by-trial basis participants were exposed to a positive, negative, or neutral picture, immediately prior to engagement in a reasoning task. After viewing and rating the valence and intensity of each picture, participants indicated by keypress whether or not the conclusion of the syllogism followed logically from the premises. The content of all syllogisms was neutral, and the influence of belief-bias was controlled for in the study design. Emotion did not affect reasoning performance, although there was a trend in the expected direction based on accuracy rates for the positive (63%) and negative (64%) versus neutral (70%) condition. Nevertheless, exposure to positive and negative pictures led to dissociable patterns of neural activation during reasoning. Therefore, the neural basis of deductive reasoning differs as a function of the valence of the context. PMID:25294997

NATO Advanced Study Institute on Mixed-Valence Compounds : Theory and Applications in Chemistry, Physics, Geology, and Biology

CERN Document Server

1980-01-01

It has been a decade since two seminal reviews demonstrated that mixed-valence compounds share many unique and fascinating features. The insight pro­ vided by those early works has promoted a great deal of both experimental and theoretical study. As a result of extensive efforts, our understanding of the bonding and properties of mixed-valence compounds has advanced substantially. There has been no compre­ hensive treatment of mixed-valence compounds since 1967, and the meeting convened at Oxford in September, 1979, provided a unique opportunity to examine the subject and its many ramifications. Mixed-valence compounds play an important role in many fields. Although the major impact of the subject has been in chemistry, its importance has become increasingly clear in solid state physics, geology, and biology. Extensive interest and effort in the field of molecular metals has demonstrated that mixed-valency is a prerequisite for high elec­ trical conductivity. The intense colors of many minerals have been s...

Sex, Age, and Emotional Valence: Revealing Possible Biases in the 'Reading the Mind in the Eyes' Task.

Science.gov (United States)

Kynast, Jana; Schroeter, Matthias L

2018-01-01

The 'Reading the Mind in the Eyes' test (RMET) assesses a specific socio-cognitive ability, i.e., the ability to identify mental states from gaze. The development of this ability in a lifespan perspective is of special interest. Whereas former investigations were limited mainly to childhood and adolescence, the focus has been shifted towards aging, and psychiatric and neurodegenerative diseases recently. Although the RMET is frequently applied in developmental psychology and clinical settings, stimulus characteristics have never been investigated with respect to potential effects on test performance. Here, we analyzed the RMET stimulus set with a special focus on interrelations between sex, age and emotional valence. Forty-three persons rated age and emotional valence of the RMET picture set. Differences in emotional valence and age ratings between male and female items were analyzed. The linear relation between age and emotional valence was tested over all items, and separately for male and female items. Male items were rated older and more negative than female stimuli. Regarding male RMET items, age predicted emotional valence: older age was associated with negative emotions. Contrary, age and valence were not linearly related in female pictures. All ratings were independent of rater characteristics. Our results demonstrate a strong confound between sex, age, and emotional valence in the RMET. Male items presented a greater variability in age ratings compared to female items. Age and emotional valence were negatively associated among male items, but no significant association was found among female stimuli. As personal attributes impact social information processing, our results may add a new perspective on the interpretation of previous findings on interindividual differences in RMET accuracy, particularly in the field of developmental psychology, and age-associated neuropsychiatric diseases. A revision of the RMET might be afforded to overcome confounds

Emotional Valence, Arousal, and Threat Ratings of 160 Chinese Words among Adolescents.

Science.gov (United States)

Ho, Samuel M Y; Mak, Christine W Y; Yeung, Dannii; Duan, Wenjie; Tang, Sandy; Yeung, June C; Ching, Rita

2015-01-01

This study was conducted to provide ratings of valence/pleasantness, arousal/excitement, and threat/potential harm for 160 Chinese words. The emotional valence classification (positive, negative, or neutral) of all of the words corresponded to that of the equivalent English language words. More than 90% of the participants, junior high school students aged between 12 and 17 years, understood the words. The participants were from both mainland China and Hong Kong, thus the words can be applied to adolescents familiar with either simplified (e.g. in mainland China) or traditional Chinese (e.g. in Hong Kong) with a junior secondary school education or higher. We also established eight words with negative valence, high threat, and high arousal ratings to facilitate future research, especially on attentional and memory biases among individuals prone to anxiety. Thus, the new emotional word list provides a useful source of information for affective research in the Chinese language.

Temperature effects in the valence fluctuation of europium intermetallic compounds

International Nuclear Information System (INIS)

Menezes, O.L.T. de; Troper, A.; Gomes, A.A.

1978-03-01

A previously reported model for valence fluctuations in europium compound in order to account for thermal occupation effect. Experimental results are critically discussed and new experiments are suggested

The Synthesis of NiO/TiO2 Heterostructures and Their Valence Band Offset Determination

Directory of Open Access Journals (Sweden)

Z. H. Ibupoto

2014-01-01

Full Text Available In this work, a heterojunction based on p-type NiO/n-type TiO2 nanostructures has been prepared on the fluorine doped tin oxide (FTO glass substrate by hydrothermal method. Scanning electron microscopy (SEM and X-Ray diffraction techniques were used for the morphological and crystalline arrays characterization. The X-ray photoelectron spectroscopy was employed to determine the valence-band offset (VBO of the NiO/TiO2 heterojunction prepared on FTO glass substrate. The core levels of Ni 2p and Ti 2p were utilized to align the valence-band offset of p-type NiO/n-type TiO2 heterojunction. The valence band offset was found to be ∼0.41 eV and the conduction band was calculated about ∼0.91 eV. The ratio of conduction band offset and the valence-band offset was found to be 2.21.