Theoretical Study of Multidimensional Proton Tunnelling in Benzoic Acid Dimer

International Journal of Molecular Sciences

Marek J. Wójcik¹  Krzysztof Szczeponek² 

[1] id="af1-ijms-04-00422">Faculty of Chemistry, Jagiellonian University, 30-060 Kraków, Ingardena 3, Pola

关键词: proton tunnelling;    energy barrier;    tunnelling splittings;   

DOI  :  10.3390/i4070422

来源: mdpi

【 摘 要 】

Ab initio B3LYP/6-311++G** calculations have been carried out for the benzoic acid dimer for the stable and saddle point structures. The energy barrier for the proton tunneling amounts to 6.5 kcal/mol. The normal mode frequencies have been computed including modes coupled to the proton tunneling mode. Two-dimensional model potentials, formed from symmetric mode coupling potential and squeezed double well potential, have been fitted to the calculated energy barrier, geometries and frequencies, and used to analyze proton dynamics. The calculated proton tunneling energy splitting in the vibrationally ground states of the low-frequency modes is ~230 cm^-1. The two-dimensional model PES predict monotonic increase of the tunneling splitting with the excitation of the planar modes. Depending of the sign of the coupling parameter out-of-plane modes can either suppress or promote the splittings.

【 授权许可】

Unknown   
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