Using ScalIT for Performing Accurate Rovibrational Spectroscopy Calculations for Triatomic Molecules: A Practical Guide

This paper presents a practical guide for use of the ScalIT software package to perform highly accurate bound rovibrational spectroscopy calculations for triatomic molecules. At its core, ScalIT serves as a massively scalable iterative sparse matrix solver, while assisting modules serve to create rovibrational Hamiltonian matrices, and analyze computed energy levels (eigenvalues) and wavefunctions (eigenvectors). Some of the methods incorporated into the package include: phase space optimized discrete variable representation, preconditioned inexact spectral transform, and optimal separable basis preconditioning. ScalIT has previously been implemented successfully for a wide range of chemical applications, allowing even the most state-of-the-art calculations to be computed with relative ease, across a large number of computational cores, in a short amount of time.