Ab initio study of the torsional potential for 9-phenylanthracene in the ground and excited states

Torsional potentials of 9-phenylanthracene both in the ground and excited states were determined by using ab initio molecular orbital calculations. Molecular structure in the ground state was optimized at the restricted Hartree–Fock level under the C2v symmetry. Then, the torsional potentials between the anthracene ring and the phenyl group in the S0 and S1 states were calculated by means of multi-reference perturbation theory based on the complete active space (CAS) SCF wave function. The present findings were consistent with the jet-laser experimental results by Barbara et al.