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Titolo:
THE EFFECT OF THE TORSIONAL BARRIER HEIGHT ON THE ACCELERATION OF INTRAMOLECULAR VIBRATIONAL-RELAXATION (IVR) BY MOLECULAR FLEXIBILITY
Autore:
PERRY DS; BETHARDY GA; WANG XL;
Indirizzi:
UNIV AKRON,DEPT CHEM AKRON OH 44325
Titolo Testata:
Berichte der Bunsengesellschaft fur Physikalische Chemie
fascicolo: 3, volume: 99, anno: 1995,
pagine: 530 - 535
SICI:
0005-9021(1995)99:3<530:TEOTTB>2.0.ZU;2-0
Fonte:
ISI
Lingua:
ENG
Soggetto:
FERMI RESONANCE STRUCTURE; EXCITED CH-CHROMOPHORE; HYDROGEN-PEROXIDE; OVERTONE SPECTROSCOPY; ENERGY REDISTRIBUTION; INTERNAL-ROTATION; H STRETCH; SPECTRUM; BEAM; LIFETIMES;
Keywords:
ENERGY TRANSFER; INTRAMOLECULAR VIBRATIONAL REDISTRIBUTION (IVR); SPECTROSCOPY, INFRARED;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
35
Recensione:
Indirizzi per estratti:
Citazione:
D.S. Perry et al., "THE EFFECT OF THE TORSIONAL BARRIER HEIGHT ON THE ACCELERATION OF INTRAMOLECULAR VIBRATIONAL-RELAXATION (IVR) BY MOLECULAR FLEXIBILITY", Berichte der Bunsengesellschaft fur Physikalische Chemie, 99(3), 1995, pp. 530-535

Abstract

Previous work by the present authors (Can. J. Chem. 72, 652 (1994)) pointed out the acceleration of IVR in flexible molecules when the prepared vibration is close to the centre of flexibility (COF). A COF was defined as a bond about which hindered internal rotation can occur thereby giving rise to molecular flexibility. Here, it is shown that the rate of IVR is inversely correlated with the height of the barrier to internal rotation for systems in which the prepared vibration is adjacent to the COF. In ethanol and hydrogen peroxide the barriers are low (approximate to 380 cm(-1)) and the relaxation of the adjacent O - H vibration is fast (4 to 26 ps). On the other hand, higher barrier torsions (1100 to 1700 cm(-1)) adjacent to the chromophore in 1-butyne, 2-fluoroethanol, and 1,2-difluoroethane give rise to much longer IVR lifetimes (270 to 565 ps). Most of the IVR lifetimes used in this paper were derived from discretely resolved spectra in which a bright state transition is fragmented into a clump of molecular eigenstates; the remainder are from rotationally selected double resonance spectra. An algorithm is described for the derivation of consistent IVR lifetimes for coupling cases ranging from intermediate down to the very sparse limitwhere only a few perturbing states are explicitly observed in the spectrum.

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Documento generato il 07/07/20 alle ore 22:15:03