MS-CASPT2 Studies on the Photophysics of Selenium-Substituted Guanine Nucleobase.

ABSTRACT: The MS-CASPT2 method has been employed to optimize minimum-energy structures of 6-selenoguanine (6SeGua) and related two- and three-state intersection structures in and between the lowest five electronic states, i.e., S₂(¹ππ*), S₁(¹ nπ*), T₂(³ nπ*), T₁(³ππ*), and S₀. In combination with MS-CASPT2 calculated linearly interpolated internal coordinate paths, the photophysical mechanism of 6SeGua has been proposed. The initially populated S₂(¹ππ*) state decays to either S₁(¹ nπ*) or T₂(³ nπ*) states through a three-state S₂/S₁/T₂ intersection point. The large S₂

SUBMITTER: Fang YG 

PROVIDER: S-EPMC6649137 | biostudies-literature | 2019 Jun

REPOSITORIES: biostudies-literature