Table 1. Relative Energy Differences (in kJ/mol) from the CASSCF/CASPT2(11,11) and RASSCF/RASPT2(19,21) Calculations.
CASSCF(11,11)a | RASSCF(19,21)a | CASPT2(11,11) | RASPT2(19,21) | |
---|---|---|---|---|
sextet | 22.6 | 57.1 | 78.1 | 108.6 |
quartet | 6.2 | 13.1 | 20.7 | 22.1 |
doublet | 0 | 0 | 0 | 0 |
The weights of the dominant configurations demonstrate the multiconfigurational character of the doublet state, and they are 46%, 25%, 15%, and 8% (CASSCF(11,11)) and 53%, 18%, 14%, and 5% (RASSCF(19,21)).