Random matrix treatment of intramolecular vibrational redistribution. II. Coriolis interactions in 1-butyne and ethanol

Journal Article · Sun Oct 01 04:00:00 EDT 1995 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.470556· OSTI ID:249402

Go, J; Perry, D S ^[1]

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

The measures are the dilution factor {phi}{sub {ital d}}, the interaction width {Delta}{epsilon}, and the effective level density {rho}{sub eff}{sup {ital c}}. In the presence of multiple coupling mechanisms (near the best fit to the ethanol {nu}{sub 14} band), the correlations between {phi}{sub {ital d}} and {Delta}{epsilon} and the bright-bath Coriolis coupling mechanisms follow the expected trends. It was also found that {rho}{sub eff}{sup {ital c}} is sensitive to the {ital x}, {ital y} Coriolis coupling {ital among} the bath states. The results were not sensitive to the {ital z}-type Coriolis coupling among the bath states in the region of the ethanol simulation, but {rho}{sub eff}{sup {ital c}} was sensitive to it in the simulation of the 1-butyne {nu}{sub 16} band. Best-fit coupling parameters were obtained for both simulated bands. The rms bright-bath {ital z}-type Coriolis coupling was found to be 0.028{plus_minus}0.005 cm{sup {minus}1} which is about three times the value obtained from a naive approach which neglects the interaction of the multiple coupling mechanisms. A direct count vibrational level density, {rho}{sub vib}, provided good agreement with the experiments when a full treatment of the torsional modes was included and a 20% enhancement of the density from neglected diagonal anharmonicities was added. A method of quantifying the conservation of the rotational quantum number, {ital K}, is provided by the inequalities, {rho}{sub vib}{le}{rho}{sub eff}{sup {ital c}}{le}(2{ital J}+1){rho}{sub vib}. For 1-butyne, {rho}{sub eff}{sup {ital c}} is closer to {rho}{sub vib} than for ethanol indicating that {ital K} is more nearly conserved. While this work treats only anharmonic and Coriolis coupling, the random matrix formalism provides the ability to treat a wide variety of coupling schemes. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

• DOE Contract Number: FG02-90ER14151
• OSTI ID: 249402
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 13 Vol. 103; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
ACETYLENE
CORIOLIS FORCE
ENERGY TRANSFER
ETHANOL
INFRARED SPECTRA
VIBRATIONAL STATES