First-Principles Study of the Lattice Dynamics of K₂SO₄

Authors

D. Liu, University of Nebraska - Lincoln
H. M. Lu, University of Nebraska - Lincoln
F. G. Ullman, University of Nebraska - Lincoln
John R. Hardy, University of Nebraska - LincolnFollow

Date of this Version

1991

Comments

Published in Phys. Rev. B 43, 6202 - 6205 (1991). Copyright © 1991 The American Physical Society. Used by permission.

Abstract

Using a newly developed first-principles approach to simulations of ionic molecular crystals, we performed static relaxation, molecular-dynamics simulation, and lattice-dynamics calculations, and measurements of the Raman spectrum, for the Pnam structure of K₂SO₄. It was found that the structure does not have the zone-center instability present in isomorphous K₂SeO₄₂ found in an earlier study. This difference between the two systems is attributed to the different charge distributions in the molecular ions. The calculated Raman-active zone-center frequencies for the Pnam structure of K₂SO₄ were found to be in general agreement with the experimental Raman frequencies.