Reactive resonances in the F + CHD3 reaction—a quantum dynamics study

Abstract

We present quantum dynamical investigations into the F + CHD(3) reaction. In our reduced dimensionality study we treat the two most important degrees of freedom, which describe the bond making and bond breaking explicitly, while treating the remaining spectator modes adiabatically. Cumulative as well as final state resolved reaction probabilities and cross sections are calculated for the two isotopic channels F + CHD(3) → FH + CD(3) and F + CHD(3) → FD + CHD(2). Our theoretical results are compared to the experimental findings of Liu and co-workers [Zhou et al., Mol. Phys., 2010, 108, 957]. Potential resonance states in the low collision energy regime are analyzed in detail employing Smith's lifetime matrix and bound state calculations.

Quantum chemistry and dynamics of the abstraction reaction of H atoms from formaldehyde

“…Fig. 3(b) presents broad oscillations for increasing energies as found in previous works [14,15,18,17,21]. The largest contribution to the cumulative reaction probability is mainly from the (ν = 0) vibrational mode at energies of interest (see Figure 3(a)).…”

“…Such behavior, also found for other systems [19,21], could be due to the application of the rectilinear coordinate projection method used for removing the contribution of 295 the two active modes from the Hessian [16,17,55]. An improvement of the results can be made with the use of curvilinear coordinates [16] to remove the contribution of nonzero gradients from the Hessian matrix and leads to better thermal rate constants.…”

“…Two active modes are treated explicitly in the scattering calculations while an approximative treatment is made for the remaining internal de- in the potential surface. This reduced dimensionality approach was successfully employed to study the H-abstraction reaction from small molecules like C1-C3 alkanes and methanol [14,15,16,17] and recently to spin-orbit non adiabatic transitions [18], to n-butane [19], cyclopropane [20] and tetramethylsilane [21]. 35 In order to analyze in details the contribution of quantum effects, we perform also semiclassical tunneling calculations on a ground-state adiabatic minimum energy path (MEP) potential.…”

Reduced dimensionality spin-orbit dynamics of CH3 + HCl $\rightleftharpoons$⇌ CH4 + Cl on ab initio surfaces

“…49 Internal degrees of freedom (DOF) are divided into two active modes explicitly treated in the quantum scattering, and 3N −8 spectator modes, which are approximately treated via inclusion of curvilinear-projected zero-point energies (ZPE) in the PES. 50,51 Variants of this approach have been successfully applied to a number of ground state reactions, 49,[52][53][54][55][56] including Cl + CH 4 − → HCl + CH 3 . 11 In this paper, the method is extended to include multisurface characterization of nonadiabatic transitions.…”

Recent advances in quantum scattering calculations on polyatomic bimolecular reactions

“…In particular, the reaction probabilities are difficult to converge at low collision energies. Earlier quantum dynamics studies were restricted to low-dimensional quantum models, which included a maximum of five degrees of freedom [238][239][240][241] .…”