Ab Initio Study of the Potential Energy Surfaces for the Reaction C + CH → C₂ + H

Abstract

The 18 lowest potential energy surfaces of C2H have been investigated with the complete active space multiconfigurational self-consistent-field method. We restricted our study to the doublet and quartet spin multiplicities. Twelve surfaces are issued from the ground-state reactants, while the six others are issued from the first excited state of the reactants. The approach of C toward CH shows no barrier for 6 of the 12 surfaces, obviously making the reaction possible at very low temperatures. The study of the potential energy curves along the reactant and product channels shows that the X, A, a, b, and c states of C2 are expected to be populated by the title reaction, even at very low temperatures. Moreover, six new equilibrium structures corresponding to the excited states of C2H are predicted.

Theoretical study of the dynamics of the reaction C(3P)+CH(X2Π)

“…[8], except they are slightly smaller than the results reported there. It is clear that the reaction occurs at very low collision energy with a large impact parameter, which is consistent with the fact that the PES is slightly attractive at long distances due to dispersion force [7]. Tang and coworkers calculated quantum results for the 1 2 A 0 PES and the 2 2 A 0 PES of C 2 H, using the three-dimensional time-dependent wave-packet method.…”

“…However, experimental work concerning the kinetics of the title reaction is very rare, with only three estimated values of the rate constant reported in the literature and databases [3][4][5]. Some theoretical calculations [6][7][8][9][10] have been carried out on the title reaction. The three-dimensional time-dependent wave-packet method [11,12] was applied to study the dynamics of the reaction C þ CH on 1 2 A 0 PES [9] and 2 2 A 0 PES [10].…”

“…Halvick and coworkers [6] calculated the electronic branching ratios between the channels opening to the formation of C 2 in the X 1 AE þ g and a 3 Å u states. Boggio-Pasqua et al [7] presented the results of a CASSCF (complete active space self-consistent field) study of some parts of the 18 lowest adiabatic PESs involved in the reaction C þ CH ! C 2 H !…”

On the temperature dependence of the rate coefficient of formation of C$_2^+$ from C + CH+

“…E-mail: srampino@thch.unipg.it in the interstellar medium are neutral-ion and neutral-neutral atomdiatom (A + BC) bimolecular reactions involving carbon and hydrogen atoms (Solomon & Klemperer 1972;Herbst 2001). In order to ground the available information on these processes on rigorous theoretical treatments, in the last fifteen years several studies either based on quasi-classical trajectory (QCT) or quantum-reactivescattering (QRS) techniques have appeared on three-atom systems such as CH 2 (see Bussery-Honvault et al (2001); Lin et al (2004); Balucani et al (2004Balucani et al ( , 2005; Defazio et al (2009) ;Joseph et al (2011); Sun et al (2013); Wu et al (2014) for reaction C + H 2 ), CH + 2 (see Herraez-Aguilar et al (2014) and Zanchet et al (2013) for reaction C + + H 2 and Stoecklin & Halvick (2005) ;Warmbier & Schneider (2011);Bovino et al (2015) for reaction CH + + H), and C 2 H (see Boggio-Pasqua et al (1998); Tang et al (2001b,a); Yang et al (2011) for reaction C + CH). On the contrary, little attention has received the positively charged variant of the latter system, C 2 H + , for which the lowest-energy atom-diatom reaction channel is the exoergic one C ( 3 P 0 ) + CH…”

THEORETICAL STUDY OF STEREO-DYNAMICS FOR THE REACTION C(3P) + CH(2II) → C2 + H ON THE THREE LOWEST POTENTIAL ENERGY SURFACES

“…20,[26][27][28] The time-dependent quantum wave packet method has been used to study the reaction C + CH by Tang et al 20 Han et al 1,[7][8][9][11][12][13][14][15][16][17][18][19] have developed the QCT method to investigate the product rotational polarization of bimolecular reactions. In the present work, the QCT method has been utilized to investigate the reaction C + CH and explore the stereo-dynamics feature of the reaction on the three lowest potential energy surfaces (PESs) reported by Boggio-pasqua et al 26,29 The four PDDCSs and the three angular distributions of P (θ r ), P (φ r ), P (θ r , φ r ) at a fixed collision energy 0.1 eV have been calculated.…”