Quantum Dynamical Study of the He + NeH⁺ Reaction on a New Analytical Potential Energy Surface

Abstract

An analytical potential energy surface (PES) for the ground state of the [HeHNe](+) system has been constructed from a set of 19,605 ab initio data points, obtained from coupled cluster singles and doubles with perturbative triples correction calculations and the aug-cc-pVQZ basis set. The PES is based on the many-body expansion form proposed by Aguado and Paniagua (J. Chem. Phys. 1992, 96, 1265), and it has a root-mean-square error of 0.03 kcal/mol. The minimum energy pathways (MEPs) for different Ne-H-He angles are calculated, and it is found that the MEP for 180° (linear) goes through the deepest potential energy well. Preliminary quantum dynamical studies are performed for the He + NeH(+) (v = 0-2, j = 0-3) → HeH(+) + Ne reaction in the 0.0-0.5 eV collision energy range. Quantum calculations are carried out using a time-dependent wave packet method within the centrifugal sudden approximation. Reaction probabilities exhibit strong oscillatory behavior arising because of the metastable [HeHNe](+). Vibrational excitation has been found to enhance the reaction cross sections.

Wave packet and statistical quantum calculations for the He + NeH+ → HeH+ + Ne reaction on the ground electronic state

“…All the QM results reported here were computed by following Chebyshev real WP propagation method. Here, it is worth mentioning that the present QM-CS results are in excellent agreement with our previous QM-CS results 36 when the previous probabilities are modified with an energy distribution calculated using spherical Hankel functions, as in the present case. The parameters used in the QM calculations are given in Table I.…”

“…A possible explanation could be the different topology of the PES of Ref. 36 depending on the value of Ne-H-He angle. Thus, whereas the minimum is observed for the 180 • collinear approach, a remarkable barrier in the minimum energy path is found for 90 • (see Fig.…”

“…4,[6][7][8][15][16][17][18][19][20][21][22][23][24][25][26] Complexes containing two rare gas atoms and a proton are also well studied. 12,[27][28][29][30][31][32][33][34][35][36] Both RgH + 2 a) t.gonzalez.lezana@csic.es b) adi07@iitg.ernet.in and [RgHRg/Rg ] + cases are found to display a global potential energy minimum at the collinear configuration. Initial theoretical studies for systems with only one proton, H + , concentrated on the determination of the stable electronic structure 27,29,30,35 and ro-vibrational energy states.…”

“…In our previous work, 36 an analytical PES was generated for the [HeHNe] + system with a very small root mean square error and preliminary quantum dynamical studies were carried out for He + NeH + → HeH + + Ne reaction following a TDWP method within CS approximation. Dense oscillatory behavior of the reaction probabilities for this reaction indicated the involvement of an intermediate complex in the reactive process, a possibility also supported by the existence of a potential well with a depth of about 0.5 eV in the region between reactants and products.…”

State-to-State Dynamics of the Ne + HeH+ (v = 0, j = 0) → NeH+(v′, j′) + He Reaction

“…30 Recently, a global analytic surface with a small root mean square error for this system has been constructed and preliminary quantum dynamical studies have been performed within centrifugal sudden (CS) approximation by some of us, for the endothermic He + NeH + → HeH + + Ne reaction. 31 Oscillatory behavior of the CS reaction probabilities suggests complex-forming mechanism as a plausible path for the reaction. Necessity of inclusion of Coriolis coupling (CC) to study bimolecular complex forming reactions has been discussed in the literature.…”