Ab initio calculation of the torsional potential for 2-alkenylanthracene in the ground and excited states

Torsional potentials between the anthracene ring and alkene planes for two 2-alkenylanthracene derivatives both in the ground- and excited-states were calculated using ab inito method as a function of dihedral angle. Molecular geometries were optimized at the restricted Hartree–Fock level in the ground-state, whereas in the excited-state at the level of configuration interaction with single excitation. In the ground-state it is s-trans conformation that is more stable and more planar. While in the excited-state both are planar and the potential shape is more like symmetrical for 2-vinylanthracence, although somewhat distorted for 2-(2′ propenyl) anthracene. Stabilization energies, barrier energies, and barrier top frequencies of both ground- and excited-states were determind