Electronic- and vibrational-structure calculations in models of the compressed SiO/sub 2/ glass system

Journal Article · Sun Jan 15 04:00:00 EST 1989 · Phys. Rev. B: Condens. Matter; (United States)

DOI:https://doi.org/10.1103/PhysRevB.39.1320· OSTI ID:6551082

Murray, R A; Ching, W Y

The electronic and vibrational structures of normal and compressed SiO/sub 2/ glasses are studied using realistic continuous-random-network models with periodic boundaries. The electronic structure is calculated by the first-principles orthogonalized linear combination of atomic orbitals (OLCAO) method and the results are presented for density of states, band gaps, effective charges, and localization of wave functions as a function of density. The vibrational density of states, infrared absorption, and Raman spectra for these models are also calculated with use of a Keating-type potential and the bond-polarizability approximation. The results are, generally, in good agreement with experiments on both normal and ''densified'' a-SiO/sub 2/. In particular, the two Raman lines at 495 and 606 cm/sup -1/ are reproduced by our calculation in direct contrast to the paracrystalline theory of SiO/sub 2/ glass. Inspection of eigenvectors in conjunction with a detailed analysis of the bonding patterns of participating atoms indicate that specific Si-O-Si angles (close to those found in threefold or fourfold rings) are responsible for these modes.

• Research Organization: Department of Physics and Astronomy, University of Kansas, Lawrence, Kansas 66045
• OSTI ID: 6551082
• Journal Information: Phys. Rev. B: Condens. Matter; (United States), Journal Name: Phys. Rev. B: Condens. Matter; (United States) Vol. 39:2; ISSN PRBMD
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360603* -- Materials-- Properties
ABSORPTION
BOND ANGLE
BOUNDARY CONDITIONS
CHALCOGENIDES
COMPRESSION
ELECTROMAGNETIC RADIATION
ELECTRONIC STRUCTURE
ENERGY GAP
ENERGY LEVELS
ENERGY-LEVEL DENSITY
EXCITED STATES
GLASS
INFRARED RADIATION
LCAO METHOD
OXIDES
OXYGEN COMPOUNDS
RADIATIONS
RAMAN SPECTRA
RANDOMNESS
SILICON COMPOUNDS
SILICON OXIDES
SPECTRA
STRUCTURAL MODELS
VIBRATIONAL STATES