Maxwell + Polarizable MD multi-scale simulation for vibrational spectroscopy

We present a novel computational scheme of classical molecular simulation that is unified with Maxwell’s equations based on a multi-scale model to describe the coupled dynamics of light electromagnetic waves and molecules in crystalline solids [1]. The charge response kernel (CRK) model, one of the polarizable force field, is then employed to incorporate electronic polarization of the molecules as the essence in the interaction with the light. The method is applicable to light-matter interaction systems that involve atomic motions in spectroscopy, photonics and optical science. Since the scheme simultaneously traces the light propagation on a macroscopic scale and the microscopic molecular motion under the light, this enables us to treat experimental setup and mimic its measurement process. We demonstrate numerical examples of vibrational spectroscopies: infrared absorption measurement of ice solid [1], and terahertz wave generation induced by ISRS (impulsive stimulated Raman scattering) in organic molecular crystal [2], DCMBI. These examples show the detailed behaviors of the interacting light fields and molecules in the spectroscopic processes.
[1] A. Yamada, J. Chem. Phys., 152, 094110 (2020)
[2] A. Yamada, submitted