Ab initio anharmonic calculations of vibrational frequencies of benzene by means of efficient construction of potential energy functions

►Ab initio anharmonic potentials for benzene were very efficiently created to the sixth order terms. ► Sampling directions for anharmonic corrections were effectively searched by the SHS method. ► Planar fundamental frequencies of benzene were reproduced with a RMS error of 3.5 cm−1. ► Various methods calculating vibrations of benzene were compared for vibronic characteristics. ► Techniques and criteria establishing well balanced anharmonic potentials were proposed.