Calculation of the Brillouin frequencies close to phase transitions in NaNO2


Yurtseven H., Caglar I.

SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY, vol.58, no.1, pp.55-65, 2002 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 58 Issue: 1
  • Publication Date: 2002
  • Doi Number: 10.1016/s1386-1425(01)00505-4
  • Title of Journal : SPECTROCHIMICA ACTA PART A-MOLECULAR AND BIOMOLECULAR SPECTROSCOPY
  • Page Numbers: pp.55-65

Abstract

We calculate here the Brillouin frequencies of the L-mode [010], [001] and [100] of NaNO2 for the phase transitions from the paraelectric phase to the sinusoidal anti-ferroelectric phase near the Neel temperature (T-N = 437.7 K) and to the ferroelectric phase near the critical temperature (T-c = 436.3 K) in this crystalline system. For calculating the frequencies, we use the thermal expansivity data for the phase regions considered, under the assumption that the mode Gruneisen parameter determined for each mode remains constant across the phase transitions. Our calculated frequencies agree well with the observed frequencies for the modes studied in NaNO2. (C) 2002 Elsevier Science B.V. All rights reserved.