Ab initio simulation of single vibronic level fluorescence spectra of anthracene using Hagedorn wavepackets

Single vibronic level (SVL) fluorescence spectroscopy contributes to the understanding of molecular vibrational structures and relaxation processes. Based on Hagedorn wavepackets, we have recently proposed a time-dependent approach to compute SVL spectra from arbitrary initial vibrational levels, i.e., higher excitations in multiple modes, and validated it against exact quantum calculations on model systems. Here, we extend the application of our method to a realistic molecular system, anthracene, employing a harmonic model constructed from ab initio electronic structure data. With the Hagedorn approach, we not only successfully reproduce the previously reported simulation results for singly excited 12¹ and 11̄¹ levels, but are also able to compute SVL spectra from multiply excited levels in good agreement with experiments and from the same Hagedorn wavepacket trajectory without any additional propagation beyond what is required for ground-state emission spectra.