Communication: Theoretical exploration of Au++H2, D2, and HD reactive collisions

Abstract

A quasi-classical study of the endoergic Au+(1S) + \documentclass[12pt]{minimal}\begin{document}${\rm H}_2(X^1 \Sigma _g^+$\end{document}H2(X1Σg+) → AuH+ (2Σ+) + H(2S) reaction, and isotopic variants, is performed to compare with recent experimental results [F. Li, C. S. Hinton, M. Citir, F. Liu, and P. B. Armentrout, J. Chem. Phys. 134, 024310 (2011)].10.1063/1.3514899 For this purpose, a new global potential energy surface has been developed based on multi-reference configuration interaction ab initio calculations. The quasi-classical trajectory results show a very good agreement with the experiments, showing the same trends for the different isotopic variants of the hydrogen molecule. It is also found that the total dissociation into three fragments, Au++H+H, is the dominant reaction channel for energies above the H2 dissociation energy. This results from a well in the entrance channel of the potential energy surface, which enhances the probability of H–Au–H insertion.

A comparative study of the Au + H2, Au+ + H2, and Au− + H2 systems: Potential energy surfaces and dynamics of reactive collisions

“…The experimental cross section to form AuH + products presents a peak about 4.60 eV, close to the total dissociation threshold and was very nicely reproduced by QCT simulations on a new three-dimensional PES. 10 In these simulations, it was found that after 4.50 eV, the total fragmentation channel cross section increases rapidly with increasing energy, becoming dominant after 5.10 eV, and of the same order.…”

“…The reaction cross section for the formation of the hydride presents a maximum for the three system, as previously reported for Au + + H 2 . 10,32 The position, height, and width of the cross section strongly depends on the system, while the total dissociation channel opens at ≈4.50 eV in all cases, the dissociation energy of H 2 .…”

“…Note that the three reactions are endoergic by 1.66, 2.79, and 3.23 eV for the neutral, cationic, and anionic systems, respectively. well in the entrance channel, of −0.91 eV, 10 shown in the MEP (Minimum Energy Path) of Figure 2 and in the bottom panel of Figure 1. In order to summarize these features, the minimum energy path (in arbitrary units) joining Au q + H 2 and AuH q + H rearrangements channels, for each q = −1, 0, +1 independently, is shown in Figure 2, and the stationary points features are listed in Table II.…”

“…These calculations were implemented in the code miQCT3, already used to treat the cationic system. 10 Calculations were performed for the ground rovibrational state of H 2 (v = 0, j = 0) and for collision energies sampled between 0.60 and 12.0 eV. The step adaptive Adams method (average step 0.05 fs) was used to integrate the set of Hamilton equations, and the conservation of both the total energy and angular momentum was carefully checked.…”

“…9 The PES of the ground electronic state presents a deep potential well which is considered the precursor of the chemisorption energy well appearing in gold nanoparticles, which originates from several curve crossings. In a similar study on the Au + + H 2 reaction, for the ground electronic state of Au + ([Xe] 4 f 14 5d 10 , 1 S), where theoretical and experimental results were found in very good agreement, 10 it has been shown that a stable AuH + 2 complex could be formed and was accessible without any barriers for this reaction marking a striking difference with the neutral case. To complete these two studies, involving the reactions of cationic and neutral gold with H 2 , it is interesting to study the behavior of the anionic gold atom in the ground electronic state ([Xe] 4 f 14 5d 10 6s 2 , 1 S), with H 2 , and compare the results with the neutral and cationic cases.…”