A quantum-rovibrational-state-selected study of the proton-transfer reaction H2+(X2Σ+g: v+ = 1–3; N+ = 0–3) + Ne → NeH+ + H using the pulsed field ionization-photoion method: observation of the rotational effect near the reaction threshold. Issue 28 (10th July 2017)

• Record Type: Journal Article
• Authors: Xiong, Bo; Chang, Yih-Chung; Ng, Cheuk-Yiu
• Is Part Of: Physical chemistry chemical physics. Volume 19:Issue 28(2017)
• Page Start: 18619
• Page End: 18627
• Publication Date: 2017-07-10
• Subjects: Chemistry, Physical and theoretical -- Periodicals; 541.3
• DOI: 10.1039/c7cp03963h
• Languages: English
• ISSNs: 1463-9076

Abstract

Abstract : The integral cross sections for the H2 + ( v + = 1–3; N + = 0–3) + Ne → NeH + + H reaction have been measured in the collision energy range of 0.05–2.00 eV for comparison of recent quantum dynamic predictions. Abstract : Using the sequential electric field pulsing scheme for vacuum ultraviolet (VUV) laser pulsed field ionization-photoion (PFI-PI) detection, we have successfully prepared H2 + ( X 2 Σ+g: v + = 1–3; N + = 0–5) ions in the form of an ion beam in single quantum-rovibrational-states with high purity, high intensity, and narrow laboratory kinetic energy spread (Δ E lab ≈ 0.05 eV). This VUV-PFI-PI ion source, when coupled with the double-quadrupole double-octupole ion–molecule reaction apparatus, has made possible a systematic examination of the vibrational- as well as rotational-state effects on the proton transfer reaction of H2 + ( X 2 Σ+g: v + ; N + ) + Ne. Here, we present the integral cross sections [σ( v + ; N + )'s] for the H2 + ( v + = 1–3; N + = 0–3) + Ne → NeH + + H reaction observed in the center-of-mass kinetic energy ( E cm ) range of 0.05–2.00 eV. The σ( v + = 1, N + = 1) exhibits a distinct E cm onset, which is found to agree with the endothermicity of 0.27 eV for the proton transfer process after taking into account of experimental uncertainties. Strong v + -vibrational enhancements are observed for σ( v + = 1–3, N + ) in the E cm range of 0.05–2.00 eV. While rotational excitations appear to have little effect on σ( v + = 3, N + ), a careful search leads to the observation of moderate N + -rotational enhancements at v + = 2: σ( v + = 2; N + = 0) < σ( v + = 2; N + = 1) < σ( v + = 2; N + = 2) < σ( v + = 2; N + = 3), where the formation of NeH + is near thermal-neutral. The σ( v + = 1–3, N + = 0–3) values obtained here are compared with previous experimental results and the most recent state-of-the-art quantum dynamics predictions. We hope that these new experimental results would further motivate more rigorous theoretical calculations on the dynamics of this prototypical ion–molecule reaction.