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Titolo:
Time resolved resonance raman, ab initio Hartree-Fock, and density functional theoretical studies on the transients states of perfluoro-p-benzoquinone
Autore:
Balakrishnan, G; Mohandas, P; Umapathy, S;
Indirizzi:
Indian Inst Sci, Dept Inorgan & Phys Chem, Bangalore 560012, Karnataka, India Indian Inst Sci Bangalore Karnataka India 560012 560012, Karnataka, India
Titolo Testata:
JOURNAL OF PHYSICAL CHEMISTRY A
fascicolo: 33, volume: 105, anno: 2001,
pagine: 7778 - 7789
SICI:
1089-5639(20010823)105:33<7778:TRRRAI>2.0.ZU;2-2
Fonte:
ISI
Lingua:
ENG
Soggetto:
CHARGE-TRANSFER COMPLEXES; RADICAL-ANIONS; VIBRATIONAL FREQUENCIES; ELECTRON-ATTACHMENT; FORCE-FIELD; FLUORANIL; SPECTROSCOPY; CHLORANIL; ENERGY; CATION;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
65
Recensione:
Indirizzi per estratti:
Indirizzo: Umapathy, S Indian Inst Sci, Dept Inorgan & Phys Chem, Bangalore 560012, Karnataka, India Indian Inst Sci Bangalore Karnataka India 560012 ataka, India
Citazione:
G. Balakrishnan et al., "Time resolved resonance raman, ab initio Hartree-Fock, and density functional theoretical studies on the transients states of perfluoro-p-benzoquinone", J PHYS CH A, 105(33), 2001, pp. 7778-7789

Abstract

In recent times, perfluorinated organic compounds have been investigated extensively to understand the influence of perfluorination on structure-reactivity correlations. Here, we report the time-resolved resonance Raman (TR3), ab initio Hartree-Fock (HF), and density functional theoretical (DFT) studies on the photogenerated transient states of perfluoro-p-benzoquinone (Fluoranil, FA). In particular, for the triplet excited states, radical anionand ketyl radical Raman spectra have been recorded. The observed Raman excitation profiles and the decay rate constants of triplet excited states of FA satisfactorily reproduce, respectively, the absorption spectra and decayrate constants reported previously from transient absorption studies. The structure and vibrational spectra of all these intermediates of FA have been calculated using both ab initio unrestricted Hartree-Fock (UHF) and density functional (UBP86) methods with standard 6-31G(d) basis set. The assignments for all the experimentally observed resonance Raman bands are made using the calculated frequencies and the normal coordinate analysis. Potentialenergy distributions (PEDs) are also presented. Perfluoro, effect is foundto be more pronounced in the triplet excited state than in the ground state or the radical anion, whereas the effect in the ground state seems to be higher than that in the radical anion. The lowest triplet excited state of FA has been identified as the pi pi* state (B-3(3G)) in nonpolar solvents and the n pi* state (B-3(1G)) in polar solvents. The solvent polarity appears to play a major role in the nature of the lowest triplet excited states, since these two states are very close to each other.

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Documento generato il 06/07/20 alle ore 05:21:56