Raman spectra from ab initio molecular dynamics and its application to liquid S-methyloxirane

We describe the calculation of Raman spectra for periodic systems via ab initio molecular dynamics (AIMD) utilizing the Gaussian and plane wave method in the program package CP2K. The electric-dipole-electric-dipole polarizability tensor has been implemented for an arbitrary shape of the simulation cell. In addition, a computationally efficient approach for its decomposition into local contributions is presented. As an example for the application of computational Raman spectroscopy to liquids, the Raman spectra of S-methyloxirane in the liquid phase have been calculated together with Raman spectra obtained from static calculations employing the double-harmonic approximation. The comparison to experimental data illustrates that a very good agreement between experiment and simulated spectra can be obtained employing AIMD, which takes into account anharmonicities and dynamical effects at ambient conditions.