Open AccessInstantaneous normal modes analysis of amorphous and supercooled silica
Author(s) -
Scott D. Bembenek,
Brian B. Laird
Publication year - 2001
Publication title -
the journal of chemical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.071
H-Index - 357
eISSN - 1089-7690
pISSN - 0021-9606
DOI - 10.1063/1.1337040
Subject(s) - supercooling , anharmonicity , normal mode , amorphous solid , glass transition , molecular dynamics , soft modes , condensed matter physics , spectral line , amorphous silica , physics , materials science , molecular physics , chemistry , crystallography , thermodynamics , nuclear magnetic resonance , quantum mechanics , vibration , chemical engineering , ferroelectricity , dielectric , engineering , polymer
The dynamics of a model for amorphous and supercooled silica (SiO2), a strong glass former, is studied using instantaneous normal mode (INM) analysis. The INM spectra at a variety of temperatures are calculated via molecular dynamics simulation. At temperatures below the glass transition temperature, the dominant contribution to the soft highly anharmonic modes comprising the imaginary frequency region of the INM spectrum are found to correspond to coupled rotations of SiO4 tetrahedral units, consistent with interpretations of neutron scattering experiments [B. B. Buchenau, H. M. Zhou, and N. Nucker, Phys. Rev. Lett. 60, 1318 (1988)] and with previous normal mode analysis of simulation results at T=0 K [S. N. Taraskin and S. R. Elliot, Phys. Rev. B 56, 8623 (1997)].
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