24.2 Implementation

Any electronic structure method can be used with radless if the necessary input, i.e. structures and vibrational data for the electronic ground and excited state, is provided. After successful calculation of the ground and excited state structures and their vibrational spectra, matrices of Eq. 24.5 are constructed at different times \(t\) to obtain the generating function. Fourier transform of the generating function together with the appropriate prefactor gives the absorption or emission spectra. Matrix products are evaluated using basic linear algebra subroutines (BLAS) [413] for real and complex matrices. The spectra are obtained by discrete Fast Fourier transformation[414] of \(G(t)\).