10 $\mu m$ INFRARED SPECTRUM OF TETRAHYDROFURAN: QUENCHING OF CORIOLIS INTERACTIONS IN THE VIBRATIONALLY EXCITED STATE
Loading...
Date
1994
Journal Title
Journal ISSN
Volume Title
Publisher
Ohio State University
Abstract
The 2 MHz resolution infrared spectrum of the asymmetric C-O stretching band of tetrahydrofuran (THF) at $1087 cm^{-1}$ has been observed using a microwave-sideband $CO_{2}$-laser electric-resonance optothermal spectrometer. Transitions arising from ground state levels up to $V=3$ in the pseudorotation quantum number have been measured; definitive band assignments have been made for $V=0 \rightarrow V=0, V=0 \rightarrow V=1, V=1 \rightarrow V=0$ and $V=1 \rightarrow V=1$ transitions. Two additional bands are observed at higher energy which are associated with higher pseudorotation levels; although the J assignments for these bands are definitive, the excited state V assignments are not. All assignments are confirmed by microwave-infrared double resonance or precise ground-state combination differences. For all four bands, the upper-state term values are found to fit to a Watson Hamiltonian to better than 10 MHz, with a few levels not included in the fits perturbed by $> 100$ MHz. Precise microwave $\Delta V$ gaps give equally precise $\Delta V$ gaps for the C-O stretching vibration. In the absence of a third perturbing state, these measurements will furnish information on the vibrational dependence of the pseudorotation portential.
Description
Author Institution: Molecular Physics Division, National Institute of Standards and Technology; Department of Chemistry, University of Virginia; Department of Chemistry, Cornell University; Abteilung chemische Physik, Universit\""{a}t Ulm; Molecular Physics Division, National Institute of Standards and Technology