Premium
Photoionization of DNA and RNA Bases, Nucleosides and Nucleotides Through a Combination of One‐ and Two‐photon Pathways upon 266 nm Nanosecond Laser Excitation ¶
Author(s) -
CrespoHernández Carlos E.,
Arce Rafael
Publication year - 2002
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1562/0031-8655(2002)0760259podarb2.0.co2
Subject(s) - photoionization , nucleotide , nanosecond , dna , excitation , chemistry , rna , laser , photon , two photon excitation microscopy , photochemistry , physics , biochemistry , optics , ionization , ion , organic chemistry , gene , quantum mechanics
The 266 nm nanosecond laser photolysis of various purine and pyrimidine derivatives results in their photoionization (PI) as one of the primary photochemical pathways. Electron photoejection occurs through a combination of one‐ and two‐photon mechanisms. The PI values depend on the substituents attached to the chromophore of the base. The net PI of the purine bases at 266 nm are of the same order of magnitude (10 −2 ) as those of the pyrimidine bases under similar experimental conditions. The monophotonic component is approximately one‐third of the net PI yield of the bases. A nonrelaxed singlet excited state intermediate is tentatively proposed for this pathway. It is proposed that this state is significantly stabilized by water solvation, transforming it into a charge transfer to solvent state from which the hydrated electron evolves.