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Modified π‐SCF MO CI calculations for anionic forms of pyrimidinic nucleic acid bases
Author(s) -
Kwiatkowski Józef S.,
Lesyng Bogdan
Publication year - 2009
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.560160727
Subject(s) - cndo/2 , uracil , chemistry , cytosine , computational chemistry , proton , configuration interaction , ground state , nucleic acid , molecule , spectral line , atomic physics , physics , organic chemistry , dna , quantum mechanics , biochemistry
The π‐scf mo ci method (within the Pariser‐Parr‐Pople scheme) is modifed to interpret the ultraviolet spectra of anionic forms of molecules and to obtain the π‐electronic charge distribution in the ground state of the anions similar to the charges calculated within the cndo/2 (or indo) procedure. The calculated positions of the electronic absorption bands for anions of uracil, its thioanalogs, cytosine, and isocytosine are in good agreement with the experimental data. In particular, the calculations predict that the monoanions of uracil and thiouracils with the proton at N 3 absorb at longer wavelengths than the corresponding monoanions with the proton at N 1 .