An efficient and numerically stable procedure for generating sextic force fields in normal mode coordinates (2019)
Type of ContentJournal Article
PublisherAMER INST PHYSICS
- Science: Journal Articles 
In this paper, we outline a general, scalable, and black-box approach for calculating high-order strongly coupled force fields in rectilinear normal mode coordinates, based upon constructing low order expansions in curvilinear coordinates with naturally limited mode-mode coupling, and then transforming between coordinate sets analytically. The optimal balance between accuracy and efficiency is achieved by transforming from 3 mode representation quartic force fields in curvilinear normal mode coordinates to 4 mode representation sextic force fields in rectilinear normal modes. Using this reduced mode-representation strategy introduces an error of only 1 cm -1 in fundamental frequencies, on average, across a sizable test set of molecules. We demonstrate that if it is feasible to generate an initial semi-quartic force field in curvilinear normal mode coordinates from ab initio data, then the subsequent coordinate transformation procedure will be relatively fast with modest memory demands. This procedure facilitates solving the nuclear vibrational problem, as all required integrals can be evaluated analytically. Our coordinate transformation code is implemented within the ex tensible PyPES library program package, at http://sourceforge.net/projects/pypes-lib-ext/.
CitationSibaev M, Crittenden DL (2019). An efficient and numerically stable procedure for generating sextic force fields in normal mode coordinates. Journal of Chemical Physics. 144(21).
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KeywordsScience & Technology; Physical Sciences; Chemistry, Physical; Physics, Atomic, Molecular & Chemical; Chemistry; Physics; POTENTIAL-ENERGY SURFACES; VIBRATIONAL-STATE CALCULATIONS; DEGENERATE PERTURBATION-THEORY; AB-INITIO DETERMINATION; POLYATOMIC-MOLECULES; SPECTROSCOPIC CONSTANTS; HARMONIC APPROXIMATION; ROVIBRATIONAL ENERGIES; QUANTUM-CHEMISTRY; WAVE-FUNCTIONS; coordinate transformation; normal mode coordinates; rectilinear; curvilinear; reduced mode representation; potential energy surface expansion
ANZSRC Fields of Research34 - Chemical sciences::3407 - Theoretical and computational chemistry::340701 - Computational chemistry
34 - Chemical sciences::3401 - Analytical chemistry::340101 - Analytical spectrometry
46 - Information and computing sciences::4601 - Applied computing::460104 - Applications in physical sciences
51 - Physical sciences::5102 - Atomic, molecular and optical physics::510201 - Atomic and molecular physics
34 - Chemical sciences::3407 - Theoretical and computational chemistry::340704 - Theoretical quantum chemistry
RightsAll rights reserved unless otherwise stated
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