Raman spectra and phase transition in betaine potassium iodide dihydrate

• Tipo: Artigo em Revista Científica Internacional
• Data: 2000

Autores

Yuzyuk, YI (Autor) Outra; Almeida, A (Autor) FCUP; Pinto, F (Autor) Outra; Chaves, MR (Autor) FCUP; Moreira, JA (Autor) Outra; Klopperpieper, A (Autor) Outra

Revista

Título: Journal of Physics Condensed Matter

Vol. 12

Páginas: 1497-1506

ISSN: 0953-8984

Editora: Institute of Physics Publishing

Indexação

ISI Web of Knowledge - 6 Citações

Scopus - 8 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Física

Outras Informações

ID Authenticus: P-001-0SY

DOI: 10.1088/0953-8984/12/7/330

Abstract (EN): Polarized Raman spectra of betaine potassium iodide dihydrate ([(CH3)(3)N+CH2 COO-](2)KI . 2H(2)O) have been studied in the temperature range 40-290 K. The behaviour of betaine external modes and of water internal vibrations provides evidence for a first order phase transition of order-disorder type at 100 K. This phase transition is related to the freezing of the successive reorientations of water molecules. The temperature dependence of the halfwidth of the water stretching band centred at 3489 cm(-1) (40 K) obeys an Arrhenius-type law corresponding to different activation energies below and above the critical temperature. The comparison of Raman and dielectric data allows us to identify two types of reorientation of water molecules.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 10