Nuclear Velocity Perturbation Theory of Vibrational Circular Dichroism.

Abstract

We report the first implementation of vibrational circular dichroism (VCD) within density functional theory (DFT) using the nuclear velocity perturbation (NVP) theory. In order to support VCD calculations in large-scale systems such as solvated (bio)molecules and supramolecular assemblies, we have chosen a plane-wave electronic structure code (CPMD). This implementation allows the incorporation of fully anharmonic effects in VCD spectra on the basis of ab initio molecular dynamics simulations. On the conceptual level, we compare our NVP results for rigid molecules with an existing implementation based on the magnetic field perturbation (MFP) technique using a Gaussian basis set and find an excellent agreement. Regarding numerical aspects, we analyze our results for their correct origin dependence and gauge invariance of the physical observables. The correlation with experimental data is very satisfactory, with certain deviations mainly due to the level of electronic structure theory used.