Global Analysis ofa-,b-, andc-Type Transitions Involving Tunneling Components ofK= 0 and 1 States of the Methanol Dimer
✍ Scribed by C.L. Lugez; F.J. Lovas; J.T. Hougen; N. Ohashi
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 518 KB
- Volume
- 194
- Category
- Article
- ISSN
- 0022-2852
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✦ Synopsis
Spectral data on K = 0 and 1 levels of the methanol dimer available from previous and present Fourier transform microwave measurements have been interpreted globally, using a group-theoretically derived effective Hamiltonian and corresponding tunneling matrix elements to describe the splittings arising from a large number of tunneling motions. In the present work, 302 new measurements (40 K = 1-1 and 262 K = 1-0 transitions) were added to the previous data set to give a total of 584 assigned transitions with J 0, essentially by making a number of real coefficients complex, as required by the generalized internal-axis-method tunneling formalism. To reduce the number of adjustable parameters to an acceptable level in both the K = 0 and K = 1 effective Hamiltonians (used in separate K = 0 and K = 1 least-squares fits), a rather large number of assumptions concerning probably negligible parameters had to be made. The present fitting results should thus be considered as providing assurance of the group-theoretical line assignments as well as a nearly quantitative global interpretation of the tunneling splittings, even though they do not yet unambiguously determine the relative contributions from all 25 group-theoretically inequivalent tunneling motions in this complex, nor do they permit quantitative extrapolation to higher K levels. Copyright 1999 Academic Press.