A theoretical insight into the photophysics of psoralen

Journal Article · Tue Mar 28 04:00:00 EST 2006 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.2178794· OSTI ID:20783252

Serrano-Perez, Juan Jose; Serrano-Andres, Luis; Merchan, Manuela ^[1]

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1. Instituto de Ciencia Molecular, Universitat de Valencia, Doctor Moliner 50, Burjassot, ES-46100 Valencia (Spain)

Psoralen photophysics has been studied on quantum chemistry grounds using the multiconfigurational second-order perturbation method CASPT2. Absorption and emission spectra of the system have been rationalized by computing the energies and properties of the low-lying singlet and triplet excited states. The S{sub 1} {pi}{pi}* state has been determined to be responsible of the lowest absorption and fluorescence bands and to initially carry the population in the photophysical processes related to the phototherapeutic properties of psoralen derivatives. The low-lying T{sub 1} {pi}{pi}* state is, on the other hand, protagonist of the phosphorescence, and its prevalent role in the reactivity of psoralen is suggested to be related to the elongation of the pyrone ring C{sub 3}-C{sub 4} bond, where the spin density is distributed on both carbon atoms. Analysis of energy gaps and spin-orbit coupling elements indicates that the efficient photophysical process leading to the population of the lowest triplet state does not take place at the Franck-Condon region but along the S{sub 1} relaxation path.

• OSTI ID: 20783252
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 12 Vol. 124; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

74 ATOMIC AND MOLECULAR PHYSICS
ABSORPTION
EMISSION SPECTRA
EXCITED STATES
FLUORESCENCE
L-S COUPLING
PERTURBATION THEORY
PHOSPHORESCENCE
PHOTOCHEMISTRY
PSORALEN
REACTION KINETICS
TRIPLETS