A global potential energy surface and time‐dependent quantum wave packet calculation of Au + H₂ reaction

Abstract

A global potential energy surface (PES) corresponding to the ground state of AuH2 system has been constructed based on 22 853 ab initio energies calculated by the multireference configuration interaction method with a Davidson correction. The neural network method is used to fit the PES, and the root mean square error is only 1.87 meV. The topographical features of the novel global PES are compared with previous PES which is constructed by Zanchet et al. (Zanchet PES). The global minimum energy reaction paths on the two PESs both have a well and a barrier. Relative to the Au + H2 reactants, the energy of well is 0.316 eV on the new PES, which is 0.421 eV deeper than Zanchet PES. The calculation of Au(2S) + H2(X1Σg+) → AuH(X1Σ+) + H(2S) dynamical reaction is carried out on new PES, by the time‐dependent quantum wave packet method (TDWP) with second order split operator. The reaction probabilities, integral cross‐sections (ICSs) and differential cross‐sections are obtained from the dynamics calculation. The threshold in the reaction is about 1.46 eV, which is 0.07 eV smaller than Zanchet PES due to the different endothermic energies on the two PESs. At low collision energy (<2.3 eV), the total ICS is larger than the result obtained on Zanchet PES, which can be attributed to the difference of the wells and endothermic energies.

Probing Reactivity of Gold Atoms with Acetylene and Ethylene with VUV Photoionization Mass Spectrometry and Ab Initio Studies

“…Since, there have been numerous experimental studies of AuH, including electronic, − vibrational, , and rotational spectra, as well as photoelectron spectroscopy of the anion . There have also been many computational studies of AuH as it is a benchmark system for high-level calculations of relativistic effects. ,− Our calculated bond length r e = 1.5393 Å is slightly longer than the experimental value, r e = 1.5237 Å . The experimental dissociation energy, D 0 = 3.22 ± 0.13 eV, is derived from extrapolation of vibrational levels of the a , b , c , and B excited electronic states, which dissociate to Au* ( 2 D 3/2 ). ,, This value is slightly higher than our calculated D 0 = 2.91 eV.…”

“…68 There have also been many computational studies of AuH, as it is a benchmark system for high-level calculations of relativistic effects. 26,[69][70][71][72][73][74] Our calculated bond length re=1.5393 Å is slightly longer than the experimental value, re=1.5237 Å. 65 The experimental dissociation energy, D0=3.22±0.13 eV, is derived from extrapolation of vibrational levels of the a, b, c and B excited electronic states, which dissociate to Au* ( 2 D3/2).…”

Nonadiabatic dynamics studies of the H(2S) + RbH(X1Σ+) reaction: based on new diabatic potential energy surfaces

“…The time-dependent wave packet (TDWP) method is a powerful theoretical tool for reaction scattering calculations, and it is widely used to calculate atom-diatom collision scattering [30][31][32] as well as the reactions involving polyatomic system. 33,34 Herein, we only make a brief introduction to the TDWP method used in the atom-diatom reaction scattering.…”

New global potential energy surface of the MgH2 system and dynamics studies of the reaction H + MgH → Mg + H2

“…TDWP is a powerful quantum computational method for studying reactive scattering problems, and is widely used in many atom‐diatom reactions and in reactions that involve polyatomics . Here, we only make a brief introduction regarding the use of the TDWP method for a triatomic reaction.…”