The overlaps of the wavefunctions between the Franck-Condon and distorted geometries were computed with the WFoverlap program, which is a part of the SHARC package. The program requires overlaps of atomic orbitals (AOs) between the two geometries, molecular orbitals (MOs), and electronic states as expansion coefficients of singly excited configurations. Using the MO coefficients of the two wavefunctions, the AO overlaps are transformed to the MO overlaps and subsequently to the overlaps between the determinants. The overlap matrix between the AO bases was computed using the ORCA 36 orca_fragovl module. The two .gbw files for both geometries required as an input can be generated for example with a Hartree-Fock calculation with no SCF iterations and the same basis set as the TD-DFT calculations. The output of orca_fragovl was then reformatted for the WFoverlap program. The 1s orbitals of non-hydrogen atoms were discarded from the overlap calculation.