The {nu}{sub 7} + {nu}{sub 9}-{nu}{sub 9} hot band in ethane
- Catholic Univ. of Nijmegen (Netherlands)
Applying an IRIR double resonance technique in a seeded molecular jet, a rotationally cooled hot band spectrum of ethane has been recorded in the region of the C-H stretching fundamental {nu}{sub 7} near 3000 cm{sup -1}. A mixture of C{sub 2}H{sub 6} and SF{sub 6} in Ar is expanded through a slit nozzle. A 10 watt cw CO{sub 2} laser excites a single rotational level in the {nu}{sub 3} manifold of SF{sub 6}. Collisional relaxation redistributes the excited state population over many rovibrational levels of C{sub 2}H{sub 6}. A continuously tunable F-center laser (FCL) then probes the changes in C{sub 2}H{sub 6} population induced by the CO{sub 2} laser. No evidence has been found for hot bands starting from excited torsional states indicating that these levels are quickly deactivated by V-T transfer to the ground state in the collisional environment of the jet. Significant population of high rotational levels in the ground state demonstrate rapid conversion of internal rotation into end-over-end rotation of the molecule. The {nu}{sub 9} state collects substantial population suggesting that this state is collisionally rather stable. The observed hot bands are assigned to the two perpendicular components of the {nu}{sub 7}+{nu}{sub 9}(A{sub 1g}{circle_plus}A{sub 2g}{circle_plus}E{sub g}) {l_arrow} {nu}{sub 9}(E{sub u}) band. The spectrum appears to be heavily perturbed by dark state interactions in the upper level forcing us to analyse each K-stack separately. Rotational levels in the {nu}{sub 7} + {nu}{sub 9} state up to J = 15 and K = 5 have been least squares fitted to standard symmetric rotor expressions with an average standard deviation of 0.0014 cm{sup -1}.
- OSTI ID:
- 437239
- Report Number(s):
- CONF-9606118-; TRN: 96:005696-0035
- Resource Relation:
- Conference: 51. Ohio State University international symposium on molecular spectroscopy, Columbus, OH (United States), 10-14 Jun 1996; Other Information: PBD: 1996; Related Information: Is Part Of Ohio State University 51st international symposium on molecular spectroscopy; PB: 272 p.
- Country of Publication:
- United States
- Language:
- English
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