摘要:

AbstractLavin's modifications of Phillips and Van Vechten (PVV) theory are discussed and hence ionic gap (Ec), homopolar gap (Eh), and ionicity (fi) are investigated for iron chalcogenides (FeS, FeS2, FeSe2, and FeTe2). A correlation between evaluated values of ionicity and Mossbauer isomeric shift is also discussed.

ISSN:0370-1972    

DOI:10.1002/pssb.2221330129

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractSolitary excitations due to the combination of an electronic excitation with intramolecular (both totally symmetric and nontotally symmetric) vibrations are shown to take place in molecular chains. Two cases are considered: a) when the molecules of the chain are fixed at their equilibrium positions and b) when the chain molecules are oscillating. In the second case solitary bound states of the chain deformation and the exciton‐intramolecular excitation can exist and propagate along the chain. The parameters of the solitons and the energy of the system are calculate

ISSN:0370-1972    

DOI:10.1002/pssb.2221330130

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe energy loss of slow atoms is studied from the viewpoint of the indirect excitation of low‐energy electron–hole pairs, i.e., the excitations of electron–hole pairs through the electron exchange process from the metal to the projectile's atomic states, and vice versa. For the slow atom,v≪vF(vandvFare the velocity of the projectile and the Fermi velocity, respectively), electrons have enough velocity for response, thus the atomic states are not well defined due to the screening effect and the electron exchange processes. By constructing the model Hamiltonian which describes such effects from first principles the stopping power at grazing incidence condition, especially for the Cs surface, is cal

ISSN:0370-1972    

DOI:10.1002/pssb.2221330131

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe density functional formalism is used to calculate the electron density, equilibrium volume, and heat of formation of ordered (CsCl‐type) alloys of nontransition metals. A cellular method is employed to separate the alloy in atomic cells with appropriate matching conditions at the cell boundaries. The ion cores are substituted by empty core pseudopotentials. The results are compared with other theoretical results and with the experimen

ISSN:0370-1972    

DOI:10.1002/pssb.2221330132

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe spatial valence electron distribution in silicon and diamond is calculated in adiabatic bond charge approximation at zero temperature when bond charges have Gaussian shape and their tensor character is taken into account. Agreement between theory and experiment is achieved. For this purpose Xia's ionic pseudopotentials and Schulze‐Unger's dielectric function are used. By two additional parametersABandZ′Bthe spatial extent is described of the bond charge and local‐field corrections, respectively. The parameterZ′Baccounts for the ratio between the Coulomb and exchange correlation interactions of the valence electrons. Its silicon and diamond values have differen

ISSN:0370-1972    

DOI:10.1002/pssb.2221330133

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractA theory developed previously is used in the analysis of ESR spectra of VO2+in ternary borate glasses. The theoretical optical basicity of these glasses is calculated. It is found that |P| and |A′‖| are larger andKis smaller in those glasses for which the optical basicity is la

ISSN:0370-1972    

DOI:10.1002/pssb.2221330134

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe kinetics of photogenerated carriers in AgBr crystals doped with trivalent iridium are investigated by photoconductivity measurements. The temperature dependence of the photoelectron lifetime is highly dependent on the level of iridium doping. Experiments show that photoelectron‐iridium reaction cross‐sections have a weak dependence on the number of vacancies bound to the iridium site. Estimates of the cross sections for electron capture a t IrBr 63−centers with one and two associated vacancies are

ISSN:0370-1972    

DOI:10.1002/pssb.2221330135

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractOn the basis of the crystal‐field theory the zero‐field splitting andg‐values of the3A2ground state for d8impurity ions in a trigonally distorted octahedral field are calculated. Using perturbation theory the analytical expressions connecting the spin‐Hamiltonian parameters with the crystal‐field parameters are obtained. It is shown that experimental data for Cu3+in Al2O3, and Ni2+in Al2O3, α‐LiIO3, LiNbO3can be explained taking into account the influence of all the excited levels on the

ISSN:0370-1972    

DOI:10.1002/pssb.2221330136

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractEPR results for copper(II) ions doped in (gly)2CaCl2· 4H2O single crystals are reported. The copper(II) complex formed in the chromophore CuN2Cl4displays rhombic crystal field symmetry with an unusual spin‐Hamiltonian parameter sequence:gx= 2.115,gy= 2.034,gz= 2.308, andAx= 40.1,Ay= 113.4,Az= −73.0 × 10−4cm−1. Theg‐factors are related to the ground state wave function α |ad x 2‐y 2−bd z 2〉 with α2= 0.86,a= 0.9835, andb= 0.181, and the untypical hyperfine splitting parameters result from the very low value of the Fermi c

ISSN:0370-1972    

DOI:10.1002/pssb.2221330137

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY

摘要:

AbstractThe frequency of the dipolar surface of small particles is calculated using the sum rule techniques due to Lushnikov et al. The effect of surface diffuseness of electron density is included. The screening of the electrons is described within the Thomas‐Fermi approximation. The lattice structure and the lattice relaxation through the introduction of pseudopotentials are taken into account. The ground state charge density is obtained from a variational estimate of the total energy of the clusters based on the local density functional formalism. The surface plasmon frequency is red‐shifted from its classical va

ISSN:0370-1972    

DOI:10.1002/pssb.2221330138

出版商:WILEY‐VCH Verlag    

年代:1986

数据来源: WILEY