The influence of Н<sub>2</sub>О<sub>2</sub> on the degradation of 8-methoxypsoralen (8-MOP) in water-ethanol solutions under the action of KrCl and XeBr excilamp radiation in a photoreactor is investigated. A kinematic model of photodegradation of the investigated molecule is constructed. In water-ethanol solutions the addition of Н<sub>2</sub>О<sub>2</sub> altered the mechanism of decay of 8-MOP under the action of a KrCl excilamp in comparison with irradiation by a XeBr excilamp. This behavior is explained by the fact that the action of 283 nm radiation leads to accumulation of a stable photoproduct. In order to establish the toxicity of this product further research is needed.
Results of theoretical research for two psoralen molecules: 8-methoxypsoralen and khellin are presented. Schemes of photophysical processes in psoralens based on quantum chemical calculation by the INDO method are analyzed. The rate constants of intersystem and internal conversions are calculated. We obtained rather high intersystem conversion constant that influences on the fluorescent yield of 8-methoxypsoralen (10<sup>7</sup> s<sup>-1</sup>) and an insignificant constant of intersystem conversion for khellin (10<sup>3</sup> s<sup>-1</sup>).
The present paper deals with compounds called photosensitizers, namely, psoralen, 3,4-phenyl-4',5'-
cyclohexylpsoralen, 4'-methyl-3,4-cycloheptyl psoralen, 4',5'-dimethyl-3,4-cyclohexyl psoralen (fig. 1). The
absorption spectra from excited triplets states were investigated. The computed triplet-triplet absorption spectra of
research compounds have been determined using INDO method. The experimental triplet-triplet absorption spectra
have been obtained using the technique of laser flash photolysis in ethanol. The compare of computed and experimental
data is shows that the computed second band wavelenght throughout agree very well (0,5-6 nm) with experimental data.
To begin with the present paper deals with compounds called photosensitizers, namely, psoralens (Ps), 21,22-dimethyl-10,11-cyclohexylpsoralen (DCP) and 10,11-phenyl-21,22-cyclohexylpsoralen (PhChP). The absorption spectra from
excited triplets states, photophysical and spectral properties occurring in molecules were investigated in this paper. The
triplet-triplet absorption spectra, spectrum S<sub>o</sub>-S<sub>i</sub>-absorption and rate constants of Ps, DCP and PhChP have been
determined using INDO method. Experimental absorption spectra of PhCIiP were obtained using CM-2203 spectrofluorimeter.
The present paper deals with compounds called photosensitizers, namely, psoralens (Ps), 4'-hydroxymethyl-4, 5', 8-
trimethyipsoralen (HMTMP) and 10,11-phenyl-21,22-cyclohexylpsoralen (PhChP). The absorption spectra from excited both singlets and triplets states were investigated in this paper. The triplet-triplet and singlet-singlet absorption spectra of PS, HMTMP and PhChP (fig. 1) have been determined using INDO method (see below).