Rate coefficients from quantum and quasi-classical cumulative reaction probabilities for the S(1D) + H2 reaction

Abstract

Cumulative reaction probabilities (CRPs) at various total angular momenta have been calculated for the barrierless reaction S( 1 D) + H 2 → SH + H at total energies up to 1.2 eV using three different theoretical approaches: time-independent quantum mechanics (QM), quasiclassical trajectories (QCT), and statistical quasiclassical trajectories ( The results show that the differences between these two PES are relatively minor and mostly related to the different topologies of the well. In addition, the agreement between the three theoretical methodologies is good, even for the highest total angular momenta and energies. In particular, the good accordance between the CRPs obtained with dynamical methods (QM and QCT) and the statistical model (SQCT) indicates that the reaction can be considered statistical in the whole range of energies in contrast with the findings for other prototypical barrierless reactions. In addition, total CRPs and rate coefficients in the range of 20-1000 K have been calculated using the QCT and SQCT methods and have been found somewhat smaller than the experimental total removal rates of S( 1 D).

Statistical properties of quantum probability fluctuations in complex-forming chemical reactions

“…[4][5][6] Since that time, it was observed that the energy-dependence of quantum reaction probabilities involve sharp fluctuations whose amplitudes tend to decrease as the energy increases. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] In the present work, we have proposed a statistical analysis of these fluctuations based in part on classical S-matrix theory, [39][40][41][42] and in part on a few assumptions, the main ones being a chaotic classical dynamics and the validity of MPPST 35 them to the benchmark H + + H 2 reaction. 14 In conclusion, we believe that the statistical tools proposed in this paper should help analyzing future quantum scattering calculations on complex-forming chemical reactions and related processes.…”

“…7,28 Since then, many studies have confirmed the previous observations. [9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27] The origin of the sharp fluctuations is rather well understood. The study of Smith life-time matrix 6,29,30 indeed reveals that fluctuations are resonance structures due to dense sets of metastable states above the dissociation limit of the intermediate complex.…”

The kinetics of X + H2 reactions (X = C(1D), N(2D), O(1D), S(1D)) at low temperature: recent combined experimental and theoretical investigations

“…Different TDWP approaches have been applied to study the S( 1 D)+H 2 [178][179][180][181], the S( 1 D)+D 2 [182] and the S( 1 D)+HD reactions [183,184] on various PESs [168,181,185,186]. Analogously, since the early work by Honvault and Launay [187] to reproduce both DCS and PTE distributions from Lee and Liu's measurements, other TIQM calculations have been reported [17,[174][175][176][177][188][189][190][191][192].…”

A new potential energy surface for the H2S system and dynamics study on the S(1D) + H2(X1Σg+) reaction

“…The S( 1 D) + H 2 (X 1 Σ g + ) → H( 2 S) + SH(X 2 Π) reactive system and its isotopic variants have been studied both experimentally1234567 and theoretically891011121314151617181920212223242526. Several experimental studies have been performed to accurately describe the equilibrium geometry and a local potential energy surface123.…”

“…The influence of the barrier on the DMBE/CBS PES at low energies was investigated9 in detail through a comparion with the results obtained on the Ho PES, and the two dynamical behaviors were very different. Jambrina et al 22 calculated the cumulative reaction probabilities of the title reaction using three different theoretical approaches: time-independent QM, QCT and statistical QCT. The agreement among the three methods was good indicating that the title reaction can be considered statistical.…”