Spectroscopic modifications of Pippard relations: Tricritical phase transition in NH4Cl
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER, cilt.102, sa.3, ss.513-518, 2006 (SCI-Expanded, Scopus)
- 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.