Strong-Field Ionization and Coulomb Explosion of Chlorine Weakly Bound to Small Water Clusters

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• 作者：Matt W. Ross ; Cuneyt Berkdemir ; A. W. Castleman ; Jr.
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：August 23, 2012
• 年：2012
• 卷：116
• 期：33
• 页码：8530-8538
• 全文大小：408K
• 年卷期：v.116,no.33(August 23, 2012)
• ISSN：1520-5215

文摘

Clusters exhibit an enhancement in ionization rates under intense, ultrafast laser pulses compared to their molecular/atomic counterparts. Studies of ionization enhancement of weakly bound molecules to clusters have not been previously characterized and quantified. We demonstrate that weakly bound ClO to (H₂O)_n (n = 1鈥?2) clusters and weakly bound HCl to (H₂O)_n (n = 1鈥?2) clusters produce high atomic charge states of chlorine via Coulomb explosion. Density functional theory (DFT) was used to qualitatively compare the interaction energy of ClO with respect to the number of water molecules as well as HCl with respect to the number of water molecules. The chlorine ion signal intensity for each atomic charge state was observed to be dependent on the molecule鈥揷luster bond strength. The observed ionization enhancement was quantified using semiclassical tunneling theory, and it was found that the Cl^3+鈥?+ and O²⁺ charge states are enhanced in ionization. Possible mechanisms of ionization enhancement are explored for weakly bound chlorine species.