Effects of Excitation Energy on the Autodetachment Lifetimes of Small Iodide-Doped ROH Clusters (R鈺怘鈥? CH3鈥? CH3CH2鈭?

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• 作者：Margaret A. Yandell ; Ryan M. Young ; Sarah B. King ; Daniel M. Neumark
• 刊名：The Journal of Physical Chemistry A
• 出版年：2012
• 出版时间：March 22, 2012
• 年：2012
• 卷：116
• 期：11
• 页码：2750-2757
• 全文大小：896K
• 年卷期：v.116,no.11(March 22, 2012)
• ISSN：1520-5215

文摘

The effect of excitation energy on the lifetimes of the charge-transfer-to-solvent (CTTS) states of small (4 鈮?n 鈮?10) iodide-doped water and alcohol clusters was explored using femtosecond time-resolved photoelectron imaging. Excitation of the CTTS state at wavelengths ranging from 272 to 238 nm leads to the formation of the I路路路(ROH)<sub>nsub><sup>鈥?/sup> (R鈺怘鈥? CH<sub>3sub>鈥? and CH<sub>3sub>CH<sub>2sub>鈭? species, which can be thought of as a vibrationally excited bare solvent cluster anion perturbed by an iodine atom. Autodetachment lifetimes for alcohol-containing clusters range from 1 to 71 ps, while water clusters survive for hundreds of ps in this size range. Autodetachment lifetimes were observed to decrease significantly with increasing excitation energy for a particular number and type of solvent molecules. The application of Klots鈥?model for thermionic emission from clusters to I<sup>鈥?/sup>(H<sub>2sub>O)<sub>5sub> and I<sup>鈥?/sup>(CH<sub>3sub>OH)<sub>7sub> qualitatively reproduces experimental trends and reveals a high sensitivity to energy parametrization while remaining relatively insensitive to the number of vibrational modes. Experimental and computational results therefore suggest that the rate of electron emission is primarily determined by the energetics of the cluster system rather than by details of molecular structure.