Electronic states of Ta2C+

Geometries and energy separations of low-lying electronic states of Ta2C+ with isosceles triangular and linear structures have been investigated. Complete active-space multiconfiguration self-consistent field method followed by large-scale multireference singles and doubles configuration interaction (MRSDCI) computations and relativistic configuration interaction that included up to two million configurations were used. The 4A2 electronic state of an isosceles triangular structure was found to be the ground state at the MRSDCI level of calculation. The electronic states of the linear structures were found to be higher.