Random matrix treatment of intramolecular vibrational redistribution. I. Methodology and anharmonic interactions in 1-butyne

Journal Article · Sat May 01 04:00:00 EDT 1993 · Journal of Chemical Physics; (United States)

DOI:https://doi.org/10.1063/1.464784· OSTI ID:6642911

Perry, D S ^[1]

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

A random matrix methodology is presented which is capable of modeling sparse through intermediate case intramolecular vibrational redistribution (IVR). A class of random Hamiltonian ensembles, called the Gaussian Poisson ensembles, is defined. These ensembles deviate from the Gaussian orthogonal ensemble (GOE) in a way that allows particular molecular spectra to be modeled, yet they can retain the desirable GOE statistical properties. The principal assumption tested by this work is that the vibrational identity of the bath states in both the calculation and in 1-butyne is sufficiently scrambled that a statistical treatment is justified. Comparison to the experimental eigenstate-resolved infrared spectra of 1-butyne is accomplished by means of four measures of IVR: the dilution factor, the interaction width, the counted level density, and the effective level density. Corrections to each of the four measures for limited experimental signal-to-noise are presented. A fit to the dilution factor and interaction width yielded the root-mean-square matrix elements for anharmonic coupling of the bright state to the bath. The values obtained, 0.010 and 0.014 cm[sup [minus]1], respectively, for the [nu][sub 1] and [nu][sub 16] bands of 1-butyne, are in close agreement with those obtained by direct deconvolution of the spectra.

• DOE Contract Number: FG02-90ER14151
• OSTI ID: 6642911
• Journal Information: Journal of Chemical Physics; (United States), Journal Name: Journal of Chemical Physics; (United States) Vol. 98:9; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

664200* -- Spectra of Atoms & Molecules & their Interactions with Photons-- (1992-)
74 ATOMIC AND MOLECULAR PHYSICS
ALKENES
BUTENES
DIFFERENTIAL EQUATIONS
DISTRIBUTION
EIGENSTATES
ENERGY LEVELS
EQUATIONS
EXCITED STATES
FUNCTIONS
GAUSS FUNCTION
HAMILTONIANS
HYDROCARBONS
INFRARED SPECTRA
INTERATOMIC FORCES
MATHEMATICAL OPERATORS
MATRICES
ORGANIC COMPOUNDS
PARTIAL DIFFERENTIAL EQUATIONS
POISSON EQUATION
QUANTUM OPERATORS
RANDOMNESS
RESOLUTION
ROTATIONAL STATES
SPECTRA
VIBRATIONAL STATES