Spectroscopic modifications of Pippard relations: Tricritical phase transition in NH4Cl


Yurtseven H. , Eraslan F.

JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, vol.102, no.3, pp.513-518, 2006 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Volume: 102 Issue: 3
  • Publication Date: 2006
  • Doi Number: 10.1016/j.jqsrt.2006.02.031
  • Title of Journal : JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
  • Page Numbers: pp.513-518

Abstract

We study here the Pippard relations modified spectroscopically for the NH4Cl crystal. By relating the specific heat C-P to the frequency shift (1/v)(partial derivative v/partial derivative T)(P) for the disorder-allowed Raman modes of v(7) (93 cm(-1)) and v(5) (144 cm(-1)) in NH4Cl close to the tricritical point (P = 1.6 kbar, T-C = 257 K), we show that the first Pippard relation is valid for this crystalline system. (c) 2006 Elsevier Ltd. All rights reserved.