Dynamics of Mg+ + H2O + He: Capture, Collisional Stabilization and Collision-Induced Dissociation

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• 作者：Emilio Martnez-Nez ; Charlotte L. Whalley ; Dmitry Shalashilin ; John M. C. Plane
• 刊名：Journal of Physical Chemistry A
• 出版年：2010
• 出版时间：June 17, 2010
• 年：2010
• 卷：114
• 期：23
• 页码：6472-6479
• 全文大小：275K
• 年卷期：v.114,no.23(June 17, 2010)
• ISSN：1520-5215

文摘

A laser flash photolysis technique and quasi-classical trajectory (QCT) calculations have been used to determine the rate coefficients for the title process. The experimental high-pressure-limiting rate coefficient is 7.0 × 10⁻¹¹ cm³ s⁻¹ at T = 300 K, which compares with the computed QCT value for the Mg⁺ + H₂O capture rate of 2.75 ± 0.08 × 10⁻⁹ cm³ s⁻¹ at the same temperature. The 39-fold difference between the experimental and simulation results is explained by further QCT calculations for the He + Mg⁺·H₂O* collision process. In particular, our simulation results indicate that collision-induced dissociation (CID) of the Mg⁺·H₂O* excited adduct is very likely compared with collisional stabilization (CS), which is an order of magnitude less likely. Including the relative rates of CID and CS in the calculation and assuming that those Mg⁺·H₂O* complexes that perform only one inner turning point in the dissociation coordinate are unlikely to be stabilized by CS, the computed rate coefficient compares well with the high-pressure experimental value.