M(O)V(I)P(AC): vibrational spectroscopy with a robust meta-program for massively parallel standard and inverse calculations.

We present the software package M(O)V(I)P(AC) for calculations of vibrational spectra, namely infrared, Raman, and Raman Optical Activity (ROA) spectra, in a massively parallelized fashion. M(O)V(I)P(AC) unites the latest versions of the programs SNF and AKIRA alongside with a range of helpful add-ons to analyze and interpret the data obtained in the calculations. With its efficient parallelization and meta-program design, M(O)V(I)P(AC) focuses in particular on the calculation of vibrational spectra of very large molecules containing on the order of a hundred atoms. For this purpose, it also offers different subsystem approaches such as Mode- and Intensity-Tracking to selectively calculate specific features of the full spectrum. Furthermore, an approximation to the entire spectrum can be obtained using the Cartesian Tensor Transfer Method. We illustrate these capabilities using the example of a large π-helix consisting of 20 (S)-alanine residues. In particular, we investigate the ROA spectrum of this structure and compare it to the spectra of α- and 3(10)-helical analogs.