Spectroscopic modifications of Pippard relations: Tricritical phase transition in NH4Cl

Yurtseven H., Eraslan F.

JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, cilt.102, sa.3, ss.513-518, 2006 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 102 Sayı: 3
  • Basım Tarihi: 2006
  • Doi Numarası: 10.1016/j.jqsrt.2006.02.031
  • Dergi Adı: JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.513-518
  • Anahtar Kelimeler: Pippard relations, Raman modes, NH4Cl, ORDER-DISORDER PHENOMENA, AMMONIUM HALIDES, SINGLE-CRYSTALS, DIAGRAM, POINTS, SYSTEM, MODEL
  • Orta Doğu Teknik Üniversitesi Adresli: Evet

Özet

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.