Semiclassical molecular dynamics for IR spectroscopy of molecules and materials

I introduce a recently developed theory for performing IR spectroscopy with semiclassical molecular dynamics.[1,2] I start by showing the theoretical details of the theory, demonstrating its high accuracy and computational effectiveness. Then, I present some applications to gas-phase molecules, showing that the method can straightforwardly be applied to large dimensional solvated systems and materials. In the final part of the talk I compare the capabilities of this semiclassical method to those of very popular path-integral methods like centroid molecular dynamics and ring polymer molecular dynamics, demonstrating why semiclassical approaches are a better choice for vibrational spectroscopy calculations and should be the preferred ones. [1] C. Lanzi, C. Aieta, M. Ceotto, R. Conte J. Chem. Phys. 160, 214107 (2024). [2] C. Lanzi, C. Aieta, M. Ceotto, R. Conte J. Chem. Phys. 163, 024122 (2025).