Influence of vibration in the reactive scattering of D + MuH: the effect of dynamical bonding

Abstract

The dynamics of the D+MuH(υ=1) reaction has been investigated using time-independent quantum mechanical calculations. Total reaction cross sections and rate coefficients have been calculated for the two exit channels of the reaction leading respectively to DMu+H and DH+Mu. Over the 100-1000K temperature range investigated the rate coefficients for the DMu+H channel are of the order of 10 −10 cm 3 s −1 and those for the DH+Mu channel vary between 1·10 −12 −8·10 −11 cm 3 s −1 . These results point to a virtually barrierless reaction for the DMu+H channel and to the presence of a comparatively small barrier for the DH+Mu channel and are consistent with the profiles of their respective collinear vibrationally adiabatic potentials (VAPs). The effective barrier in the VAP of the DH+Mu channel is located in the reactants valley and, consequently, translation is found to be more efficient than vibration for the promotion of the reaction over a large energy interval in the post threshold region. Below this barrier, the DH+Mu channel can be accessible through an indirect mechanism implying a crossing from the DMu+H pathway.The most salient feature found in the present study is revealed in the total reaction cross section for the DMu+H channel, which shows a sharp resonance caused by the presence of a deep well in the vibrationally adiabatic potential. This well has a dynamical origin, reminiscent of that found recently in the vibrationally bonded BrMuBr complex [Fleming et al. Angew. Chem. Int. Ed. 53, 1, 2014], and is due to the stabilizing effect of the light Mu atom oscillating between the heavier H and D isotopes and to the bond softening associated with vibrational excitation of MuH.

How intrinsic nuclear nonadiabaticity affects molecular structure, electronic density, and conformational stability: Insights from the multicomponent DFT calculations of Mu/H isotopologues

“…The thermalization of a positive muon would lead to the formation of muonium (Mu) atom, discovered experimentally by Hughes et al in 1960, which is conceived as a lighter isotope of hydrogen [28][29][30][31][32][33] . This is further established in the light of the comparative chemical kinetic investigations and recent theoretical studies regarding the "independent chemical identity" of the muonium atom with respect to the other members of the Periodic Table [34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] .…”

Effect of isotope on state-to-state dynamics for reactive collision reactions O(3P)+H2+→OH++H and O(3P)+H2+→OH+H+ in ground state 12A″ and first excited 12A′ potential energy surfaces*

“…This phenomenon is consistent with Polanyi's rule, [48] and this kind of vibrational inversion also exists in many other reactions. [49][50][51][52][53] Because of energy conservation, for a given E C , the maximum j value reached in the distribution decreases as v increases. According to the analysis in Ref.…”