ANHARMONIC EFFECTS ON LATTICE VIBRATION MODES OF SILLENITES

Citation
P. Beneventi et al., ANHARMONIC EFFECTS ON LATTICE VIBRATION MODES OF SILLENITES, Radiation effects and defects in solids, 134(1-4), 1995, pp. 293-297
Citations number
7
Categorie Soggetti
Physics, Condensed Matter","Nuclear Sciences & Tecnology
ISSN journal
10420150
Volume
134
Issue
1-4
Year of publication
1995
Pages
293 - 297
Database
ISI
SICI code
1042-0150(1995)134:1-4<293:AEOLVM>2.0.ZU;2-A
Abstract
High resolution FTIR absorption spectroscopy in the 600-3500 cm(-1) wa venumber and 9-300 K temperature ranges was applied to study multi-pho non transitions of the tetrahedral unit modes in BSO, EGO, BTO and mix ed BSO-BGO sillenite crystals. Up to four-phonon (overtones of the F m ode and combination of F and A modes) transitions were detected in EGO , BSO, and BTO and up to three- in the mixed crystals. The F mode anha rmonicity, evaluated in the framework of the Morse oscillator model, w as in the range 0.0024-0.0056. Fine structures due to Si-isotopes were observed in BSO. The two- and three-phonon transitions in the mixed c rystals were well described by a two-mode behaviour.