Ring-polymer molecular dynamics: Rate coefficient calculations for energetically symmetric (near thermoneutral) insertion reactions (X + H[subscript 2]) → HX + H(X = C([superscript 1]D), S([superscript 1]D))

Abstract

Following our previous study of prototypical insertion reactions of energetically asymmetric type with the RPMD (Ring-Polymer Molecular Dynamics) method [Y. Li, Y. Suleimanov, and H. Guo, J. Phys. Chem. Lett. 5, 700 (2014)], we extend it to two other prototypical insertion reactions with much less exothermicity (near thermoneutral), namely, X + H[subscript 2] → HX + H where X = C([superscript 1] D), S([superscript 1] D), in order to assess the accuracy of this method for calculating thermal rate coefficients for this class of reactions. For both chemical reactions, RPMD displays remarkable accuracy and agreement with the previous quantum dynamic results that make it encouraging for the future application of the RPMD to other barrier-less, complex-forming reactions involving polyatomic reactants with any exothermicity.