摘要:

AbstractUsing the theoretical model developed recently for liquid3He, the pressure dependent zero‐sound velocities atT= 0 K are calculated by a self‐consistent procedure. Introducing a pseudopotential for the effective interaction between two3He atoms of parallel and antiparallel spin, reasonable agreement with the experimental data of Wheatley et al. is found. An exact agreement with the experimental value is obtained by introducing a term into the theory to account for the local field corrections to the bare particle‐hole propagator beyond the random phase approximation (RPA) in a parametric way. The present theory seems to indicate the propagation of a new kind of sound wave in liqu

ISSN:0370-1972    

DOI:10.1002/pssb.2221690105

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221690136

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221690137

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA three‐body potential (TBP) model is used to describe the cohesive and anharmonic properties of strontium, barium, and lead nitrates of fluorite structure. This TBP model consists of the long‐range Coulomb and three‐body interactions and the short‐range van der Waals attraction and overlap repulsion effective up to the second neighbour ions. This model reveals a better description of the cohesion, third‐, and fourth‐order elastic constants, and pressure derivatives of the second‐order elastic constants of these nitrates than those obtained by earlier workers. The scope for improvements is a

ISSN:0370-1972    

DOI:10.1002/pssb.2221690106

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221690138

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA microscopic theory for the investigation of the short‐range order effects on electron–phonon interaction in binary alloys is proposed. An expression for the electron–phonon matrix element is derived. Due to the presence of disorder in alloys, an additional term arises in this matrix element in comparison to the case of pure metal. The influence of pair correlations on the Eliashberg function α2F(ω) and the electron–phonon interaction constant in alloys of the KRb and KCs systems is investigated numerically and is analyzed. The pair correlations are shown to cause an increase of the electron–phonon interaction constant in the vicinity of the phase instability point. Under certain conditions such an increase m

ISSN:0370-1972    

DOI:10.1002/pssb.2221690107

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

ISSN:0370-1972    

DOI:10.1002/pssb.2221690139

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractThe heat capacity and the pressure dependence of the phase transition temperature of CoZrF6are measured. The first order phase transition Fm3m → R3is characterized by large values of both, the entropy change ΔS= (5.8 ± 0.8) J mol−1K−1and the rate of increase of the transition temperatureT0with applied hydrostatic pressure, dT0/dp= (340 ± 40) K GPa−1. An analysis of the results is performed in terms of the Landau theory. The parameters of the thermodynamic potential are

ISSN:0370-1972    

DOI:10.1002/pssb.2221690108

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractIn a thin epitaxial film on a substrate, misfit dislocations at the interface can reduce the elastic energy due to coherency stresses. When the elastic moduli of film and substrate are different, the misfit dislocations are repelled towards the softer material. Their equilibrium positions are derived.

ISSN:0370-1972    

DOI:10.1002/pssb.2221690109

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY

摘要:

AbstractA Green‐function calculation is performed to investigate how the presence of impurities affects the spectral properties of the adatom and surface atoms of a semi‐infinite linear chain. The infinite set of equations is solved using the transfer matrix method, and inverting a single complex matrix that contains all information about a finite region of the chain including the adatom, the surface, and the impurity sites. The method permits to calculate the local properties on each site of the contaminated region in a very efficient form. Results of the exact calculations of the electronic densities of states are presented when a single impurity is put in many different positions and when a set of seven impurities is distributed in two different forms in the ch

ISSN:0370-1972    

DOI:10.1002/pssb.2221690110

出版商:WILEY‐VCH Verlag    

年代:1992

数据来源: WILEY