Accurate computations of vibrational energies and vibrational spectra of molecules require inclusion of the anharmonic forces. In standard computational protocols, this leads to a large vibrational Hamiltonian matrix that needs to be diagonalized.
Spectral intensities are calculated for individual transitions separately. In this work, an alternate direct generation of the spectral curves is proposed, based on a temporal propagation of a trial vibrational wave function followed by the Fourier transformation (FT).
The lack of the lengthy and computer-memory-demanding diagonalization thus makes the FT procedure especially convenient for spectral simulations of larger molecules.