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Instanton calculations of tunneling splittings in chiral molecules
Author(s) -
Sahu Nityananda,
Richardson Jeremy O.,
Berger Robert
Publication year - 2021
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.26447
Subject(s) - pseudopotential , instanton , coupled cluster , isotopomers , ab initio , chemistry , quantum tunnelling , perturbation theory (quantum mechanics) , molecule , ab initio quantum chemistry methods , physics , basis set , ground state , atomic physics , computational chemistry , quantum mechanics
We report the ground state tunneling splittings (Δ E ± ) of a number of axially chiral molecules using the ring‐polymer instanton (RPI) method ( J. Chem. Phys ., 2011 , 134 , 054109). The list includes isotopomers of hydrogen dichalcogenides H 2 X 2 (X = O, S, Se, Te, and Po), hydrogen thioperoxide HSOH and dichlorodisulfane S 2 Cl 2 . Ab initio electronic‐structure calculations have been performed on the level of second‐order Møller–Plesset perturbation (MP2) theory either with split‐valance basis sets or augmented correlation‐consistent basis sets on H, O, S, and Cl atoms. Energy‐consistent pseudopotential and corresponding triple zeta basis sets of the Stuttgart group are used on Se, Te, and Po atoms. The results are further improved using single point calculations performed at the coupled cluster level with iterative singles and doubles and perturbative triples amplitudes. When available for comparison, our computed values of Δ E ± are found to lie within the same order of magnitude as values reported in the literature, although RPI also provides predictions for H 2 Po 2 and S 2 Cl 2 , which have not previously been directly calculated. Since RPI is a single‐shot method which does not require detailed prior knowledge of the optimal tunneling path, it offers an effective way for estimating the tunneling dynamics of more complex chiral molecules, and especially those with small tunneling splittings.