Lattice dynamics, phase transitions and hydrogen effective charges of betaine phosphite: a comparison with betaine phosphate and their deuterated analogues

• Tipo: Artigo em Revista Científica Internacional
• Data: 1998

Autores

Santos, ML (Autor) FCUP; Almeida, A (Autor) FCUP; Moreira, JA (Autor) Outra; Chaves, MR (Autor) FCUP; Klopperpieper, A (Autor) Outra; Gervais, F (Autor) Outra

Revista

Título: Journal of Physics Condensed Matter

Vol. 10

Páginas: 6147-6169

ISSN: 0953-8984

Editora: Institute of Physics Publishing

Indexação

ISI Web of Knowledge - 6 Citações

Scopus - 6 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Física

Outras Informações

ID Authenticus: P-001-7FR

DOI: 10.1088/0953-8984/10/27/015

Abstract (EN): The temperature dependence of complete infrared reflection spectra of a betaine phosphite single crystal is reported for the polarizations parallel to a and b axes in the wavenumber range from 10 to 5000 cm(-1). They are compared with previous data that were limited to the range 10-600 cm(-1). They are also compared with reflectivity spectra of betaine phosphate, betaine arsenate, deuterated betaine phosphite single crystals and betaine compressed powder. These comparisons allow a mode assignment. Spectra were fitted with the factorized form of the dielectric function. The role of phonons in the behaviour of the dielectric constant in the vicinity of the ferroelectric (FE)-paraelectric (PE) phase transition is discussed. The decrease of effective charges along the FE axis below the FE-PE phase transition is assigned to an increase of oxygen-hydrogen electronic orbital hybridization related to the change of average bond-length.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 23