Rings, intermediate-range order and vibrational spectra of chalcogenide glasses

Conference · Sat Oct 01 00:00:00 EDT 1988

OSTI ID:6526053

Vashishta, P; Kalia, R K; Ebbsjoe, I

Short-range order, intermediate-range order and vibrational density of states of vitreous GeSe2 are investigated using the molecular dynamics (MD) method. The static structure factor exhibits the first sharp diffraction peak (FSDP), a characteristic of intermediate-range order in chalcogenide glasses, as well as all the other peaks observed in structural measurements. The anomalous dependence of the FSDP, i.e. the decrease in its height on cooling is due to frustration enhanced by the increased density. The calculated phonon density of states in the glass shows peaks at 8.0, 10.8, 26.4, 34.4, and 37.2 MeV, which are all in good agreement with neutron experiments. In addition a companion line, A/sub 1c/, to the symmetric breathing mode A1 (26.4 MeV) is identified with a feature at 27.8 MeV. Raman studies also find A/sub 1c/ to be /approximately/1.5 MeV higher than the A1 mode. Our calculations show that the A/sub 1c/ mode arises due to vibrations of tetrahedra belonging to 5- and 7-fold rings. 12 refs., 4 figs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6526053
• Report Number(s): CONF-880726-5; ON: DE89005887
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360602* -- Other Materials-- Structure & Phase Studies
BOND ANGLE
BOND LENGTHS
CHALCOGENIDES
CRYSTAL STRUCTURE
DENSITY
DIMENSIONS
ENERGY LEVELS
EXCITED STATES
GERMANIUM COMPOUNDS
GERMANIUM SELENIDES
GLASS
LENGTH
MOLECULAR STRUCTURE
PHYSICAL PROPERTIES
SELENIDES
SELENIUM COMPOUNDS
VIBRATIONAL STATES