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Numerical study of pseudowave-functions for alkali atoms
Solid State Communications, Vol. 20, pp. v—vu, 1976.
Pergamon Press.
Printed in Great Britain
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids ‘J Phys. Chem. Solids (to be published)’ should be cited in references to material quoted from this section prior to the publication of the relevant article. 1.
SHELL MODEL CALCULATION OF STACKING FAULT ENERGIES IN THE FLUORITE STRUCTURE R.J. Gaboriaud, M. Boisson and J. Grilhe, Facultd des Sciences, 40 Avenue du Rec Recteur Pineau, 86022 Poitiers, France.
A detailed measurement of the temperature dependencé of the tracer diffusivity of substantial sodium ion in AgBr indicates the activation energy of the formation of a Frenkel pair to be temperature.dependent. The approach used earlier by Muller and by Aboagye and Friauf in interpreting the “extra” ionic conductivity at high temperatures as due to an anomalous increase in the defect concentrations thus appears to be essentially correct. However, the decreases in defect formation enthalpy at high temperatures, as deduced from these diffusion experiments, are somewhat smaller than those obtained earlier from conductivity data. Also, the activation enthalpy for the jumping of a sodium ion into a neighboring vacancy is found to be nearly twice that for motion of a free vacancy, the increased migration
A shell model computation of stacking fault energies in the fluorite structure is developed. Ionic and electronic polarization are taken into account. It is shown that the polarization energy is low when the defect is relaxed. The results are compared with those obtained using the Born classical model. Stacking fault energies values are found too high to be connected with dislocation splitting, Received 29 April 1976 Revised 2 September 1976 2.
barrier presumably resulting from the absence of covalent interactions in the case of the sodium ion.
NUMERICAL STUDY OF PSEUDOWAVEFUNCTIONS FOR ALKALI ATOMS 4. R.D. Zwicker, Department of Physics, University of the Witwatersrand, Johannesburg, South Africa.
Smooth pseudowavefunctions based on known valence and core functions are calculated and displayed for atomic Li, Na, and K. These are used to examine some of the approximations employed in pseudopotential calculations in particular, that of replacing the pseudowavefunction by a constant in the core region. The possibility of neglecting inner core states in pseudopotential calculations is discussed in the light of pseudowavefunctions calculated using only the core state of highest energy.
CYCLOTRON RESONANCE IN LEAD I, TIPPING EFFECT OF MAGNETIC FIELD Yoshichika Onuki, Hiroyoshi Suematsu and Sei-ichi Tanuma, The Institute for Solid State —
Physics, The University of Tokyo, Roppongi, Minato-ku, Tokyo 106, Japan. The cyclotron resonances in lead in field tipped geometry have observed foroflarge angles up to 40°from thebeen sample surfaces the tipping (111) and (100)
—
planes. In addition to the resonance of the orbit ~ on a cylindrical arm of the electron Fermi surface, two new series of resonances, ~A and ~B have been found, of which the cyclotron masses are very close to that of ~ but which differ slightly in tipping angle dependence.
Received 20 April 1976 3.
Received 18 June 1976
The mass of ~A is dependent on microwave frequency, so that ~.A is attributed to the Doppler-shifted cyclotron resonance of a non-stationary orbit near whose location is discussed in relation to the Fermi surface model of Van Dyke. In field geometry normal to the (100) surface, two series of resonances have been observed, which are characterized as the extinction of even numbered harmonic resonances. This effect arises from the skipping orbit which has a trajectory topologicaily
A STUDY OF THE HIGH-TEMPERATURE TRANSPORT ANOMALY IN AgBr, BY DIFFUSION OF SODIUM TRACER A.P. Batra and L.M. Slifkin, Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514, U.S.A.
~,
v
Pergamon Press.
Printed in Great Britain
Abstracts of Articles to be Published in The Journal of Physics and Chemistry of Solids ‘J Phys. Chem. Solids (to be published)’ should be cited in references to material quoted from this section prior to the publication of the relevant article. 1.
SHELL MODEL CALCULATION OF STACKING FAULT ENERGIES IN THE FLUORITE STRUCTURE R.J. Gaboriaud, M. Boisson and J. Grilhe, Facultd des Sciences, 40 Avenue du Rec Recteur Pineau, 86022 Poitiers, France.
A detailed measurement of the temperature dependencé of the tracer diffusivity of substantial sodium ion in AgBr indicates the activation energy of the formation of a Frenkel pair to be temperature.dependent. The approach used earlier by Muller and by Aboagye and Friauf in interpreting the “extra” ionic conductivity at high temperatures as due to an anomalous increase in the defect concentrations thus appears to be essentially correct. However, the decreases in defect formation enthalpy at high temperatures, as deduced from these diffusion experiments, are somewhat smaller than those obtained earlier from conductivity data. Also, the activation enthalpy for the jumping of a sodium ion into a neighboring vacancy is found to be nearly twice that for motion of a free vacancy, the increased migration
A shell model computation of stacking fault energies in the fluorite structure is developed. Ionic and electronic polarization are taken into account. It is shown that the polarization energy is low when the defect is relaxed. The results are compared with those obtained using the Born classical model. Stacking fault energies values are found too high to be connected with dislocation splitting, Received 29 April 1976 Revised 2 September 1976 2.
barrier presumably resulting from the absence of covalent interactions in the case of the sodium ion.
NUMERICAL STUDY OF PSEUDOWAVEFUNCTIONS FOR ALKALI ATOMS 4. R.D. Zwicker, Department of Physics, University of the Witwatersrand, Johannesburg, South Africa.
Smooth pseudowavefunctions based on known valence and core functions are calculated and displayed for atomic Li, Na, and K. These are used to examine some of the approximations employed in pseudopotential calculations in particular, that of replacing the pseudowavefunction by a constant in the core region. The possibility of neglecting inner core states in pseudopotential calculations is discussed in the light of pseudowavefunctions calculated using only the core state of highest energy.
CYCLOTRON RESONANCE IN LEAD I, TIPPING EFFECT OF MAGNETIC FIELD Yoshichika Onuki, Hiroyoshi Suematsu and Sei-ichi Tanuma, The Institute for Solid State —
Physics, The University of Tokyo, Roppongi, Minato-ku, Tokyo 106, Japan. The cyclotron resonances in lead in field tipped geometry have observed foroflarge angles up to 40°from thebeen sample surfaces the tipping (111) and (100)
—
planes. In addition to the resonance of the orbit ~ on a cylindrical arm of the electron Fermi surface, two new series of resonances, ~A and ~B have been found, of which the cyclotron masses are very close to that of ~ but which differ slightly in tipping angle dependence.
Received 20 April 1976 3.
Received 18 June 1976
The mass of ~A is dependent on microwave frequency, so that ~.A is attributed to the Doppler-shifted cyclotron resonance of a non-stationary orbit near whose location is discussed in relation to the Fermi surface model of Van Dyke. In field geometry normal to the (100) surface, two series of resonances have been observed, which are characterized as the extinction of even numbered harmonic resonances. This effect arises from the skipping orbit which has a trajectory topologicaily
A STUDY OF THE HIGH-TEMPERATURE TRANSPORT ANOMALY IN AgBr, BY DIFFUSION OF SODIUM TRACER A.P. Batra and L.M. Slifkin, Department of Physics and Astronomy, University of North Carolina, Chapel Hill, NC 27514, U.S.A.
~,
v