Competing mechanisms for intramolecular vibrational redistribution in the [nu][sub 14] asymmetric methyl stretch band of [ital trans]-ethanol

Journal Article · Wed Dec 15 04:00:00 EST 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.465524· OSTI ID:5800160

Bethardy, G A; Perry, D S ^[1]

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1. Department of Chemistry, The University of Akron, Akron, Ohio 44325-3601 (United States)

The extensively perturbed spectrum of the asymmetric methyl stretching vibration of [ital trans]-ethanol near 2990 cm[sup [minus]1] has been reinvestigated via direct absorption infrared spectroscopy at a resolution of 30 MHz. A ground state combination difference analysis of the vibrational state mixing is presented for the upper state levels [ital K][sub [ital a]][sup [prime]] = 0--2 and [ital J][prime]=0--4. The analysis indicates that the rotationless 0[sub 00] level is anharmonically coupled to the dark bath states. The effective number of perturbing states in each rovibrational transition increases with both [ital J] and [ital K][sub [ital a]] providing evidence for rotational involvement in intramolecular vibrational redistribution (IVR). The decrease of the average dilution factor from [phi][sub [ital d]]=0.41 at [ital K][sub [ital a]][sup [prime]] = 0 to [phi][sub [ital d]]=0.09 at [ital K][sub [ital a]][sup [prime]] = 2 and the increase of the average interaction width from [Delta][epsilon]=0.04 cm[sup [minus]1] at [ital K][sub [ital a]][sup [prime]] = 0 to [Delta][epsilon]=0.19 cm[sup [minus]1] at [ital K][sub [ital a]][sup [prime]] = 2 indicate an [ital a]-type Coriolis component to the bright-bath coupling. In the [ital K][sub [ital a]][sup [prime]] = 0 series the dilution factor decreases rapidly from [phi][sub [ital d]]=0.92 at [ital J][prime]=0 to [phi][sub [ital d]]=0.14 at [ital J][prime]=3 indicating that [ital b],[ital c]-type Coriolis coupling also plays a significant role in the IVR process. The effective level density [rho][sub eff][sup [ital c]] for all of the observed transitions lie above the total vibrational state density [rho][sub vib]=9 levels per cm[sup [minus]1] and most are closer to the total rovibrational state density [rho][sub rovib]=(2[ital J]+1)[rho][sub vib].

• DOE Contract Number: FG02-90ER14151
• OSTI ID: 5800160
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 99:12; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
664400 -- Experimentally Derived Information on Atomic & Molecular Properties-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION SPECTRA
ALCOHOLS
ALKYL RADICALS
ASYMMETRY
CORIOLIS FORCE
COUPLING
ENERGY LEVELS
ETHANOL
EXCITED STATES
FREQUENCY MIXING
FREQUENCY RANGE
GROUND STATES
HYDROXY COMPOUNDS
INFRARED SPECTRA
INTERATOMIC FORCES
LIFETIME
MATHEMATICAL SPACE
METHYL RADICALS
MHZ RANGE
MHZ RANGE 01-100
MOLECULES
ORGANIC COMPOUNDS
PHASE SPACE
POLYATOMIC MOLECULES
QUANTUM NUMBERS
RADICALS
RESOLUTION
ROTATIONAL STATES
SPACE
SPECTRA
VIBRATIONAL STATES