MICROWAVE MEASUREMENTS OF THE $V=O\rightarrow 1$ AND $V=2\rightarrow 3$ PSEUDOROTATION BANDS OF TETRAHYDROFURAN
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Date
1994
Journal Title
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Publisher
Ohio State University
Abstract
The microwave spectrum of tetrahydrofuran $(C_{4}H_{8}O)$ was first observed by Engerholm, {et al.}$^{1}$ $\Delta V=0$ transitions from levels up to $V = 8$ in the psuedrorotation quantum number were reported. The $V = 0$ and 1 and $V = 2$ and 3 levels are strongly Coriolis perturbed and were estimated to be separated by 19.5(1.5)GHz and 45(15) GHz respectively. We have extended the microwave measurements for the $V = 0, 1, 2$ and 3 pseudorotation states in the 10 MHz to 40 GHz region using an electric resonance optothermal spectrometer with a microwave synthesizer. The extremely weak c-type transitions between the $V = 0 \rightarrow 1$ and $V = 2 \rightarrow 3 $ levels have been measured for the first time. Their assignments are verified by double resonance with 10 $\mu m$ infrared transitions arising from common around states. The $V = 0$ and 1, and $V = 2$ and 3 data sets are fit separately to a Watson Hamiltonian supplemented by a {b}-type Coriolis term. The standard deviations of the fits are = 1MHz and 3 MHz respectively, and the $V = 0 \rightarrow 1$ and $V = 2 \rightarrow 3 $ gaps are now precisely determined as 21301(1) MHz and 4668(2) MHz. The splittings together with the precise Coriolis constants will allow a refinement of the pseudorotation potential.
Description
$^{1}$. G. Engerbolm, A, Lunz and W. Gwinn J. Chem. Phys., 50, 2446 (1969).
Author Institution: Molecular Physics Division, National Institute of Standards and Technology; Department of Chemistry, University of Virginia; Molecular Physics Division, National Institute of Standards and Technology
Author Institution: Molecular Physics Division, National Institute of Standards and Technology; Department of Chemistry, University of Virginia; Molecular Physics Division, National Institute of Standards and Technology