Using symmetry-adapted optimized sum-of-products basis functions to calculate vibrational spectra

Abstract

Vibrational spectra can be computed without storing full-dimensional vectors by using low-rank sum-of-products (SOP) basis functions. We introduce symmetry constraints in the SOP basis functions to make it possible to separately calculate states in different symmetry subgroups. This is done using a power method to compute eigenvalues and an alternating least squares method to optimize basis functions. Owing to the fact that the power method favours the convergence of the lowest states, one must be careful not to exclude basis functions of some symmetries. Exploiting symmetry facilitates making assignments and improves the accuracy. The method is applied to the acetonitrile molecule.

References in corpus (1)

• Calculating vibrational spectra with sum of product basis functions without storing full-dimensional vectors or matrices

Cited by in corpus (4)

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• Comparison of different eigensolvers for calculating vibrational spectra using low-rank, sum-of-product basis functions
• Benchmarking vibrational spectra: 5000 accurate eigenstates of acetonitrile using tree tensor network states
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