Hybrid Classical-Quantum Algorithm to Simulate ECD spectra -Case Study on the Tryptophan Zwitterion in Water

Abstract

The vibronic structure of electronic circular dichroism (ECD) spectra is simulated in silico using a hybrid method that encompasses ab initio time-dependent density functional theory (TD-DFT) calculations and the Doktorov quantum algorithm. As case study, the four dominant low-energy electronic excitations of the zwitterionic form of the tryptophan amino acid are characterized and their ECD spectra are simulated with and without considering partial Duschinsky rotation effects. The Duschinsky-based normal mode mixing is shown to have a small impact on the vibronic structure, demonstrating the versatility of the quantum algorithm where individual normal mode contributions to the vibronic structure of the spectrum are considered.