Hot Band Spectroscopy of Acetylene after Intermolecular Vibrational Energy Transfer from Ethylene
✍ Scribed by J. Oomens; J. Reuss
- Publisher
- Elsevier Science
- Year
- 1995
- Tongue
- English
- Weight
- 508 KB
- Volume
- 173
- Category
- Article
- ISSN
- 0022-2852
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✦ Synopsis
A rotationally cooled hot band spectrum of acetylene in the (3300-\mathrm{cm}^{-1}) region has been recorded using an IR-IR double resonance technique on an argon-seeded supersonic jet containing two different molecular species, ethylene and acetylene. After excitation of ethylene by a (\mathrm{cw}{2}) laser, collisional energy transfer from ethylene to acetylene populates the low-lying modes (\left(\nu{4}, \nu_{5}, 2 \nu_{4}\right.), and (2 \nu_{5}) ) in acetylene. Several hot bands starting from these vibrationally excited levels have been observed by applying an FCL laser as a probe. A high-resolution spectrum has been recorded from 3306 to (3268 \mathrm{~cm}^{-1}) and from 3258 to (3256 \mathrm{~cm}^{-1}), including six previously unresolved (Q) branches assigned to six different (\Pi-\Pi) and (\Delta-\Delta) hot band transitions. In total, more than 50 new lines have been assigned. Effective (l)-type doubling constants have been determined for the upper states of the hot bands. Separate linear least-squares fits have been applied to the transition wavenumbers for each sub- (Q)-branch, yielding rotational constants in good agreement with literature values, where available, derived from the (P) and (R) branches. O 1995 Academic Press, Inc.