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Titolo:
Acetylene at the threshold of isomerization
Autore:
Jacobson, MP; Field, RW;
Indirizzi:
MIT, Dept Chem, Cambridge, MA 02139 USA MIT Cambridge MA USA 02139MIT, Dept Chem, Cambridge, MA 02139 USA MIT, George R Harrison Spect Lab, Cambridge, MA 02139 USA MIT Cambridge MA USA 02139 R Harrison Spect Lab, Cambridge, MA 02139 USA
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY A
fascicolo: 14, volume: 104, anno: 2000,
pagine: 3073 - 3086
SICI:
1089-5639(20000413)104:14<3073:AATTOI>2.0.ZU;2-8
Fonte:
ISI
Lingua:
ENG
Soggetto:
INTRAMOLECULAR VIBRATIONAL REDISTRIBUTION; DISPERSED FLUORESCENCE-SPECTRA; ANHARMONIC-OSCILLATOR MODEL; EXTENDED CROSS-CORRELATION; POTENTIAL-ENERGY SURFACE; HIGHLY EXCITED ACETYLENE; LOCAL MODES; APPROXIMATE CONSTANTS; PATTERN-RECOGNITION; MOLECULAR-SPECTRA;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
83
Recensione:
Indirizzi per estratti:
Indirizzo: Field, RW MIT, Dept Chem, Cambridge, MA 02139 USA MIT Cambridge MA USA 02139 , Dept Chem, Cambridge, MA 02139 USA
Citazione:
M.P. Jacobson e R.W. Field, "Acetylene at the threshold of isomerization", J PHYS CH A, 104(14), 2000, pp. 3073-3086

Abstract

This article reviews recent research on acetylene which is intended as a contribution to the understanding of intramolecular vibrational energy flow when it is poorly described by either statistical (i.e., RRKM) or purely separable (i.e., harmonic oscillator/normal mode) models. The experimental spectra that inform this investigation are similar to 7 cm(-1) resolution dispersed fluorescence spectra of the acetylene S-1-->S-0 system. Above 10 000cm(-1) of vibrational energy, these spectra are extremely congested and cannot be analyzed using conventional spectroscopic assignment procedures. Instead, a numerical pattern recognition procedure is utilized to disentanglespectroscopic patterns that are associated with approximately conserved polyad quantum numbers. This pattern recognition analysis makes possible detailed modeling of the short-time (similar to 1 ps) but large-amplitude vibrational dynamics of acetylene at high energy (15 000 cm(-1)), which is demonstrated here to be dominated by regularity even for the low-frequency bending motions (22 quanta of bend excitation). That is, a few stable motions dominate the large-amplitude bending dynamics, including local bend (one hydrogen bending), which is closely related to the acetylene-vinylidene isomerization coordinate, and a new type of vibrational motion that we call counter-rotation, in which the two hydrogens undergo circular motions on oppositeends of the CC core.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 13/08/20 alle ore 14:31:01