Smolyak Algorithm Adapted to a System-Bath Separation: Application to an Encapsulated Molecule with Large-Amplitude Motions

Lauvergnat, David; Chen, Ahai; Benoit, David M.; Scribano, Yohann; Nauts, André; DavidLauvergnat

Abstract

A Smolyak algorithm adapted to system-bath separation is proposed for rigorous quantum simulations. This technique combines a sparse grid method with the system-bath concept in a specific configuration without limitations on the form of the Hamiltonian, thus achieving a highly efficient convergence of the excitation transitions for the "system"part. Our approach provides a general way to overcome the perennial convergence problem for the standard Smolyak algorithm and enables the simulation of floppy molecules with more than a hundred degrees of freedom. The efficiency of the present method is illustrated on the simulation of H2 caged in an sII clathrate hydrate including two kinds of cage modes. The transition energies are converged by increasing the number of normal modes of water molecules. Our results confirm the triplet splittings of both translational and rotational (j = 1) transitions of the H2 molecule. Furthermore, they show a slight increase of the translational transitions with respect to the ones in a rigid cage.

Citation

Lauvergnat, D., Chen, A., Benoit, D. M., Scribano, Y., Nauts, A., & DavidLauvergnat. (2022). Smolyak Algorithm Adapted to a System-Bath Separation: Application to an Encapsulated Molecule with Large-Amplitude Motions. Journal of chemical theory and computation : JCTC, https://doi.org/10.1021/acs.jctc.2c00108

• Journal Article Type: Article
• Acceptance Date: Apr 25, 2022
• Online Publication Date: May 18, 2022
• Publication Date: Jan 1, 2022
• Deposit Date: Jun 8, 2022
• Publicly Available Date: Jan 2, 2023
• Journal: Journal of Chemical Theory and Computation
• Print ISSN: 1549-9618
• Electronic ISSN: 1549-9626
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• DOI: https://doi.org/10.1021/acs.jctc.2c00108
• Keywords: Algorithms; Basis sets; Energy; Molecules; Solvates
• Public URL: https://hull-repository.worktribe.com/output/3999452