Computational Photochemistry

Experimental and DFT Computational Insight into Nitrosamine Photochemistry-Oxygen Matters.

A nitrosamine photooxidation reaction is shown to generate a peroxy intermediate by experimental physical-organic methods. The irradiation of phenyl and methyl-substituted nitrosamines in the presence of isotopically labeled 18-oxygen revealed that an O atom was trapped from a peroxy intermediate to trimethylphosphite or triphenylphosphine, or by nitrosamine itself, forming two moles of nitrami...

Computational reference data for the photochemistry of cyclobutane pyrimidine dimers.

The cis-syn cyclobutane pyrimidine dimer is one of the major classes of carcinogenic UV-induced DNA photoproducts. In this work, diverse high-level quantum-chemical methods were used to determine the spectroscopic properties of neutral (singlet and triplet) and charged (cation and anion) species of thymine dimers. Maps of potential energy, charge distribution, electron affinity, and ionization ...

Matrix isolation and computational study of the photochemistry of 1,3,2,4-benzodithiadiazine.

Photolysis of 1,3,2,4-benzodithiadiazine (1) at ambient temperature yields stable 1,2,3-benzodithiazolyl radicals. In order to reveal the mechanism of this unusual transformation, the photochemistry of 1 was studied in argon matrices using IR and UV-vis spectroscopy. A series of intermediates, including four- and five-membered heterocyclic and o-quinoid acyclic species, were characterized spect...

Advances in computational photochemistry and chemiluminescence of biological and nanotechnological molecules

Benign decay vs. photolysis in the photophysics and photochemistry of 5-bromouracil. A computational study.

The excited state potential energy surface of 5-bromouracil has been studied with ab initio CASPT2//CASSCF calculations to rationalize the competition between the benign decay and the photolysis found experimentally. The surface is characterized by an extended region of degeneracy between S(1) and S(0). The access to this region has been studied with minimum energy path calculations from the FC...