Far-infrared spectra and two-dimensional potential energy surfaces involving the ring-puckering vibration of 2,5-dihydrothiophene
- BDM Petroleum Technologies, Bartlesville, OK (United States)
- Texas A and M Univ., College Station, TX (United States). Dept. of Chemistry
The far-infrared spectra of 2,5-dihydrothiophene not only show the principle ring-puckering series in the 87--127 cm{sup {minus}1} region but also possess two sideband series arising from the ring-twisting first and second excited states. A third series arises from puckering transitions in the excited state of the {upsilon}{sub 9}(A{sub g}) in-plane ring angle bending vibration, which occurs at 509.9 cm{sup {minus}1}. The ring-puckering levels in the {upsilon}{sub 9} excited state are also confirmed by observed sum, difference, and hot bands. Observed double-quantum transitions confirm many of these assignments. Each of the four series can be fit well with a one-dimensional single minimum potential function possessing positive quartic and quadratic terms. Two-dimensional potential energy surfaces were also calculated to assess the interaction of the ring-puckering with the ring-twisting and in-plane ring bending modes. The twisting is anticooperative, raising the energy of the puckering process, while the in-plane ring bending is cooperative, facilitating the puckering motion.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States); Welch (Robert A.) Foundation, Houston, TX (United States); Texas Advanced Research Program, TX (United States); USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States)
- DOE Contract Number:
- AC22-94PC91008
- OSTI ID:
- 335225
- Journal Information:
- Journal of Physical Chemistry A: Molecules, Spectroscopy, Kinetics, Environment, amp General Theory, Vol. 103, Issue 7; Other Information: PBD: 18 Feb 1999
- Country of Publication:
- United States
- Language:
- English
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