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Electronic structure of the pyrimidine and purine components of nucleic acids in their ground and lower excited singlet and triplet states
Author(s) -
Savin F. A.,
Morozov Yu. V.,
Borodavkin A. V.,
Chekhov V. O.,
Budowsky E. I.,
Simukova N. A.
Publication year - 1979
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.560160414
Subject(s) - cndo/2 , chemistry , excited state , ionic bonding , singlet state , electronic structure , pyrimidine , ground state , molecule , valence (chemistry) , nucleic acid , atomic electron transition , computational chemistry , triplet state , atomic physics , molecular physics , spectral line , ion , quantum mechanics , physics , stereochemistry , organic chemistry , biochemistry
Quantum‐chemical calculation of the energies of the electronic transitions and the electronic structures of the neutral and ionic species of the nucleic acids components in their ground and lower excited singlet and triplet ππ* and n π* states has been carried out in the all‐valence‐electron approximation CNDO / S . The results of the calculation allow one to identify the most photoreactive sites of the molecules and to consider the dependence of the location of these sites on the ionic state of the molecules. The calculated data are compared with our previous results obtained in a π‐electron approximation. The individual absorption spectra of various ionic and tautomeric species of the nucleic acids components obtained by us earlier have been decomposed into bands corresponding to separate electronic transitions. As a rule, there is a good agreement between the calculated data in the two approximations and the experimental results.