Quantum chemical study of biradical decay channels in cytidine nucleosides

The biradical radiationless decay mechanism of the excited electronic state structure of the cytidine, 5-fluorocytidine, and deoxycytidine nucleosides are theoretically studied. Nucleoside radiationless decay pathways are compared with those of the isolated bases and qualitatively, mechanisms of cytosine nucleosides are found to be similar to those of the isolated cytosine base.