Communication: The origin of rotational enhancement effect for the reaction of H{sub 2}O{sup +} + H{sub 2} (D{sub 2})
- Department of Chemistry and Chemical Biology, University of New Mexico, Albuquerque, New Mexico 87131 (United States)
- Department of Biology and Chemistry, City University of Hong Kong, Kowloon (Hong Kong)
We have measured the absolute integral cross sections (σ’s) for H{sub 3}O{sup +} formed by the reaction of rovibrationally selected H{sub 2}O{sup +}(X{sup 2}B{sub 1}; v{sub 1}{sup +}v{sub 2}{sup +}v{sub 3}{sup +} = 000; N{sup +}{sub Ka}{sup +}{sub Kc}{sup +} = 0{sub 00}, 1{sub 11}, and 2{sub 11}) ion with H{sub 2} at the center-of-mass collision energy (E{sub cm}) range of 0.03–10.00 eV. The σ(0{sub 00}), σ(1{sub 11}), and σ(2{sub 11}) values thus obtained reveal rotational enhancements at low E{sub cm} < 0.50 eV, in agreement with the observation of the previous study of the H{sub 2}O{sup +}(X{sup 2}B{sub 1}) + D{sub 2} reaction. This Communication presents important progress concerning the high-level ab initio quantum calculation of the potential energy surface for the H{sub 2}O{sup +}(X{sup 2}B{sub 1}) + H{sub 2} (D{sub 2}) reactions, which has provided valuable insight into the origin of the rotational enhancement effect. Governed by the charge and dipole-induced-multipole interactions, the calculation shows that H{sub 2} (D{sub 2}) approaches the H end of H{sub 2}O{sup +}(X{sup 2}B{sub 1}) in the long range, whereas chemical force in the short range favors the orientation of H{sub 2} (D{sub 2}) toward the O side of H{sub 2}O{sup +}. The reorientation of H{sub 2}O{sup +} reactant ion facilitated by rotational excitation thus promotes the H{sub 2}O{sup +} + H{sub 2} (D{sub 2}) reaction along the minimum energy pathway, rendering the observed rotational enhancement effects. The occurrence of this effect at low E{sub cm} indicates that the long range charge and dipole-induced-multipole interactions of the colliding pair play a significant role in the dynamics of the exothermic H{sub 2}O{sup +} + H{sub 2} (D{sub 2}) reactions.
- OSTI ID:
- 22253659
- Journal Information:
- Journal of Chemical Physics, Vol. 140, Issue 1; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
Similar Records
Near infrared overtone (vOH = 2 ← 0) spectroscopy of Ne–H2O clusters
Improved source of NF(b sup 1. Sigma. sup + ) molecules: Spectroscopic constants and evidence for E-V energy-transfer reactions with CH sub 4 and H sub 2 O