Beyond Born-Oppenheimer theory for ab initio constructed diabatic potential energy surfaces of singlet H3+ to study reaction dynamics using coupled 3D time-dependent wave-packet approach

• Published in: The Journal of chemical physics Vol. 147; no. 7; p. 074105
• Main Authors: Ghosh, Sandip, Mukherjee, Saikat, Mukherjee, Bijit, Mandal, Souvik, Sharma, Rahul, Chaudhury, Pinaki, Adhikari, Satrajit
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 21.08.2017
• Subjects: Adiabatic flow; Angular momentum; Charge transfer; Collision dynamics; Helicity; Mathematical analysis; Potential energy; Quantum numbers; Rate constants; Time dependence; Workability
• ISSN: 0021-9606; 1089-7690; 1089-7690
• DOI: 10.1063/1.4998406

The workability of beyond Born-Oppenheimer theory to construct diabatic potential energy surfaces (PESs) of a charge transfer atom-diatom collision process has been explored by performing scattering calculations to extract accurate integral cross sections (ICSs) and rate constants for comparison with most recent experimental quantities. We calculate non-adiabatic coupling terms among the lowest three singlet states of H3+ system (11A′, 21A′, and 31A′) using MRCI level of calculation and solve the adiabatic-diabatic transformation equation to formulate the diabatic Hamiltonian matrix of the same process [S. Mukherjee et al., J. Chem. Phys. 141, 204306 (2014)] for the entire region of nuclear configuration space. The nonadiabatic effects in the D+ + H2 reaction has been studied by implementing the coupled 3D time-dependent wave packet formalism in hyperspherical coordinates [S. Adhikari and A. J. C. Varandas, Comput. Phys. Commun. 184, 270 (2013)] with zero and non-zero total angular momentum (J) on such newly constructed accurate (ab initio) diabatic PESs of H3+. We have depicted the convergence profiles of reaction probabilities for the reactive non-charge transfer, non-reactive charge transfer, and reactive charge transfer processes for different collisional energies with respect to the helicity (K) and total angular momentum (J) quantum numbers. Finally, total and state-to-state ICSs are calculated as a function of collision energy for the initial rovibrational state (v = 0, j = 0) of the H2 molecule, and consequently, those quantities are compared with previous theoretical and experimental results.