THE GROUND STATE TORSION-ROTATION SPECTRUM OF PROPARGYL ALCOHOL ($HCCCH_{2}OH$)
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Date
1996
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Ohio State University
Abstract
The ground state torsion-rotation spectrum of the asymmetric internal hydroxyl rotation in propargyl alcohol ($HCCCH_{2}OH$) has been investigated in the 84 to 640 GHz range. The ground state has been confirmed to consists of two torsional sub-states of the gauche $conformer^{a}$, a symmetric gauche state ($gauche^{+}$) and an antisymmetric gauche state ($gauche^{-}$). No evidence of a low lying third state or trans conformer has been observed. The more stable gauche + state is 652389.5 MHz below the gauche- state. Due to their close proximity, the two gauche states interact strongly through a series of $a$- and $b$-type corilolis interactions. Strong $a$- and weak $b$-dipole rotational transitions are observed within each sub-state while strong $c$-dipole rotational transitions are observed between the two sub-states. Over 2300 transitions covering a range of J and $K_{a}$ values to 80 and 34, respectively, have been fit to experimental accuracy using a fixed-frame-axis method (FFAM) Hamiltonian. The rotation, distortion and interaction constants have been determined. The 652 GHz gauche + gauche- energy difference, strong $gauche^{+}$ to gauche- transitions and the constants derived from the analysis should enable rapid astronomical detection.
Description
$^{a}$Eizi Hirota, J. Mol. Spectrasc. 26, 335 (1968).
Author Institution: Jet Propulsion Laboratory, California Institute of Technology
Author Institution: Jet Propulsion Laboratory, California Institute of Technology