Matrix--molecule interactions, dynamics, and exchange phenomena in low temperature matrices: SF/sub 6/ in argon and krypton
High resolution infrared studies of argon/SF/sub 6/ and krypton/SF/sub 6/ matrices at 10 000/1 show an unexpected amount of structure; 10--12 peaks are observed in argon and six or more peaks in krypton matrices for the ..nu../sub 3/ mode. Studies in which the deposition temperatures are varied, in conjunction with the structure observed for combination modes and temperature reversible spectral changes, allowed differentiation between multiple trapping sites and site symmetry splittings. We conclude that there are at least six different sites for monomeric SF/sub 6/ in argon and at least three sites in krypton. Two sites in argon and two in krypton exhibit site symmetry splittings. Temperature dependence studies have shown striking spectral changes wherin for three of these sites (one in argon and two in krypton) the peaks, due to site symmetry splitting, coalesce as the temperature is raised. The temperature dependence can be explained in terms of exchange dephasing involving two high energy fundamentals and a local phonon mode. The dynamics associated with motional collapse of the high enery fundamentals corresponds to rapid site-to-site exchange on a less than nanosecond time scale resulting in higher effective site symmetry as observed by infrared. Unusual /sup 32/S--/sup 34/S isotope effects have also been observed for the spectra of these low temperature matrices.
- Research Organization:
- Los Alamos Scientific Laboratory, University of California, Los Alamos, New Mexico 87545
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6524489
- Journal Information:
- J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 74:6; ISSN JCPSA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Molecular & Chemical Physics-- Atomic & Molecular Properties & Theory
74 ATOMIC AND MOLECULAR PHYSICS
ARGON
ELEMENTS
FLUIDS
FLUORIDES
FLUORINE COMPOUNDS
GASES
HALIDES
HALOGEN COMPOUNDS
INFRARED SPECTRA
INTERMOLECULAR FORCES
KRYPTON
LOW TEMPERATURE
MATRIX ISOLATION
NONMETALS
RARE GASES
SPECTRA
SULFUR COMPOUNDS
SULFUR FLUORIDES
TEMPERATURE DEPENDENCE