Mode selective stereomutation tunnelling in hydrogen peroxide isotopomers

Mode Selective Stereomutation and Parity Violation in Disulfane Isotopomers H2S2, D2S2, T2S2

“…It has also been successfully applied to the inversion dynamics of aniline [19]. Moreover, it has been shown that our harmonic reaction-path Hamiltonian approach gives good agreement with the results of a new fully coupled six-dimensional adiabatic channel approach [18] [47]. We compare the torsional tunneling splittings of the disulfane isotopomers with parity-violating potentials [29] 2.…”

“…In this paper, we present our theoretical results for the mode-selective stereomutation tunneling in disulfane isotopomers. The calculations were performed employing the quasiadiabatic channel reaction-path Hamiltonian (RPH) approach [18] [19], which has been shown to reproduce well the experimentally observed pure torsional spectrum and mode-specific tunneling, as well as the few known isotope shifts for H 2 O 2 , a related molecule. The reaction path Hamiltonian used here is based on earlier work by Miller, Handy, and Adams [43], and further related to still earlier adiabatic channel model [44] [45] and transition-state-theory treatments [46].…”

“…The torsional-tunneling dynamics were calculated with the quasiadiabatic channelreaction path Hamiltonian treatment described in detail in [18] [19]. In brief, it is a modified version of the RPH treatment introduced by Miller, Handy, and Adams [43].…”

“…Avoided crossings of adiabatic channels are removed in the modified approach by a systematic deperturbation by means of 2 Â 2 diabatic rotations in normal coordinate space. For details, we refer to [18] [19]. The existing computer program package from [18] [19] was modified to allow for much higher numerical precision.…”

“…For details, we refer to [18] [19]. The existing computer program package from [18] [19] was modified to allow for much higher numerical precision. We use 128-bit word length (quadruple precision) for a floating-point number.…”