pyVib, a computer program for the analysis of infrared and Raman optical activity.

A new program called pyVib has been developed as a tool for the analysis of Gaussian (Gaussian 03, Gaussian Inc., Pittsburgh, PA) outputs of vibrational absorption (IR), Raman as well as vibrational optical activity (VOA) spectra calculations. This program has been designed to help the computational chemistry practitioner in the task of analyzing and visualizing molecular vibrations and cross sections. In particular, the analysis of absorption and scattering cross sections can be done using new tools such as group coupling matrices (GCMs) and atomic contribution patterns (ACPs) as either 2D or 3D representations, respectively (Hug, Chem Phys 2001, 264, 53). It reads the Hessian, the atomic polar tensors (APTs), the atomic axial tensors (AATs) (Nafie, J Chem Phys 1983, 79, 4950), and the gradients of the various polarizability tensors involved in VOA calculations and stored in Gaussian fchk ascii files. pyVib is capable of picking suitably chosen atoms or group of atoms for evaluating the contribution of each atom or defined groups of atoms to the calculated VOA scattered intensities. All the results generated by pyVib can be visualized in real-time but can also be transferred to text editors and electronic spreadsheets, which facilitate a detailed subsequent analysis and the visualization by other graphical user interfaces (GUIs).This program is coded in Python and used the visualization toolkit (VTK) library. It is freely available under the terms of the general GNU public license (GPL) for Linux platforms.