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Titolo:
SOLVENT EFFECTS ON MOLECULAR-SPECTRA .2. SIMULATIONS OF HYDRATED CLUSTERS AND DILUTE-SOLUTIONS OF PYRIMIDINE IN ITS LOWEST (N,PI-ASTERISK) SINGLET EXCITED-STATE
Autore:
ZENG J; HUSH NS; REIMERS JR;
Indirizzi:
UNIV SYDNEY,DEPT PHYS & THEORET CHEM SYDNEY NSW 2006 AUSTRALIA UNIV SYDNEY,DEPT BIOCHEM SYDNEY NSW 2006 AUSTRALIA
Titolo Testata:
The Journal of chemical physics
fascicolo: 3, volume: 99, anno: 1993,
pagine: 1496 - 1507
SICI:
0021-9606(1993)99:3<1496:SEOM.S>2.0.ZU;2-B
Fonte:
ISI
Lingua:
ENG
Soggetto:
TIME-RESOLVED FLUORESCENCE; FREE-ENERGY; POTENTIAL FUNCTIONS; ELECTRONIC-SPECTRA; ABSORPTION-SPECTRA; NUCLEIC-ACIDS; FORCE-FIELD; WATER; DYNAMICS; FORMALDEHYDE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
92
Recensione:
Indirizzi per estratti:
Citazione:
J. Zeng et al., "SOLVENT EFFECTS ON MOLECULAR-SPECTRA .2. SIMULATIONS OF HYDRATED CLUSTERS AND DILUTE-SOLUTIONS OF PYRIMIDINE IN ITS LOWEST (N,PI-ASTERISK) SINGLET EXCITED-STATE", The Journal of chemical physics, 99(3), 1993, pp. 1496-1507

Abstract

Hydrogen bonding between pyrimidine in its lowest (n,pi) singlet excited state and water in dilute solution is investigated using NPT-ensemble Monte Carlo simulations, and the properties of the pyrimidine-water complex are examined using molecular dynamics. The 1(n,pi) excitation, known experimentally to be delocalized in the gas phase, is shownto remain delocalized when pyrimidine undergoes hydrogen bonding. Assuming that the intermolecular interactions are electronic state independent, Kollman's Lennard-Jones interactions are combined with molecular charges obtained in four different ways, generating a variety of intermolecular pair potentials. It is found that, in solution, both pyrimidine-water-hydrogen bonds are considerably weakened in the excited state; however, on average, one hydrogen bond per pyrimidine remains. The excited state hydrogen bonding gives rise to structures in the liquid more like those found in van der Waals bonded systems than in strongly hydrogen-bonded systems such as ground-state pyrimidine in water. Ablue shift of the absorption band origin is correctly predicted and its magnitude and Franck-Condon contribution are in reasonable agreement with experiment. For pyrimidine-water clusters, minor changes in theintermolecular potential surfaces are shown to cause major qualitative differences in the excited state cluster dynamics, mimicking the observed spectral properties of several different hydrogen-bonded pyrimidine clusters.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 02/12/20 alle ore 13:42:39