Raman spectra and phase transition in betaine potassium iodide dihydrate

• Type: Article in International Scientific Journal
• Date: 2000

Authors

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

Journal

Title: Journal of Physics Condensed Matter

Vol. 12

Pages: 1497-1506

ISSN: 0953-8984

Publisher: Institute of Physics Publishing

Indexing

ISI Web of Knowledge - 6 Citations

Scopus - 8 Citations

Scientific classification

FOS: Natural sciences > Physical sciences

Other information

Authenticus ID: 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.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 10