Exploring approximate geometries of minimum energy conical intersections by TDDFT calculations

[Display omitted] •We proposed a method to optimize approximate S0/S1-MECI structures using TDDFT.•The energy shift method was used to avoid discontinuities on TDDFT-PES around CIs.•The S0/S1-MECI geometries and energies at multireference theories were reproduced.•An automated MECI search method was combined to explore approximate S0/S1-MECIs.•All the S0/S1-MECIs of benzene and naphthalene were explored. An approach is proposed to obtain approximate geometries for minimum energy conical intersections between the ground and first excited singlet electronic states (S0/S1-MECIs) using the time-dependent density functional theory (TDDFT). This approach uses the energy shift method to avoid discontinuities on TDDFT potential energy surfaces around conical intersections. It is shown numerically that the approximate S0/S1-MECIs of benzene and naphthalene obtained by this approach qualitatively reproduce the geometries and energies of the S0/S1-MECIs obtained by multireference theories. Moreover, the performance of the present approach when combined with an automated MECI searching method is examined through applications to benzene and naphthalene.