Density functional theory study of the conformational space of phenyl benzoate, a common fragment in many mesogenic molecules

The complete conformational space of phenyl benzoate (three coupled rotors) has been studied by B3LYP density functional theory (DFT) at the 6-31+G* basis set level. The overall quality of the DFT results has been checked via Moller-Plesset second-order perturbation theory (MP2) calculations performed on a few significant molecular geometries. Contrary to the general belief, we have found that rotation around the C(= O)-O bond is not more restricted than rotation around the C(=O)-C bond. We have commented on the location and magnitude of the molecular dipole moment and their dependence on conformation. The energy data have been fitted through an expression containing a Fourier expansion plus a Lennard-Jones term, suitable to be used in computer simulations or to assist analysis of experimental data.