Group-theoretical treatment of tunneling splittings in the methanol dimer
Journal Article
·
· Journal of Molecular Spectroscopy; (United States)
- Kanazawa Univ. (Japan). Dept. of Physics
- National Inst. of Standards and Technology, Gaithersburg, MD (United States). Molecular Physics Div.
The methanol dimer is of interest as a small prototype hydrogen-bonded system, as a molecule with multidimensional tunneling splittings, and as a possible precursor in the catalytic conversion of methanol to gasoline. Tunneling splitting patterns, selection rules, and effective B values for K = 0 rotational levels of the hydrogen-bonded methanol dimer are predicted from group-theoretical considerations, a modified internal axis method, approximate descriptions of possible tunneling paths, and the assumption that K = 0 levels can be treated by themselves. It is shown that 25 different tunneling motions are possible when the two methanol monomers are identical, giving rise to 16 tunneling-rotational levels for K = 0: four nondegenerate A levels, eight doubly degenerate E levels, and four fourfold degenerate G levels. The gross features of a recently observed dimer K = 0 [alpha]-type microwave spectrum can be explained using only two of these tunneling motions, namely the internal rotation of each of the two inequivalent methyl groups in the dimer. Finer details of the observed splittings presumably arise from some of the remaining 23 tunneling motions. Tunneling splitting patterns are also predicted for cases in which the two methanols in the dimer are isotopically different, but the C[sub 3v] symmetry of both methyl tops is preserved.
- OSTI ID:
- 5449856
- Journal Information:
- Journal of Molecular Spectroscopy; (United States), Journal Name: Journal of Molecular Spectroscopy; (United States) Vol. 163:1; ISSN JMOSA3; ISSN 0022-2852
- Country of Publication:
- United States
- Language:
- English
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