https://scholars.lib.ntu.edu.tw/handle/123456789/623502
標題: | Vibrational predissociation spectra and hydrogen-bond topologies of H +(H2O)9-11 | 作者: | CHIH-KAI LIN Wu C.-C. Wang Y.-S. Lee Y.T. Chang H.-C. Kuo J.-L. Klein M.L. |
公開日期: | 2005 | 卷: | 7 | 期: | 5 | 起(迄)頁: | 938-944 | 來源出版物: | Physical Chemistry Chemical Physics | 摘要: | Vibrational predissociation spectra of protonated water clusters H +(H2O)n, n = 9-11, are presented. Examination of the spectra in the free-OH stretching region revealed predominance of a single absorption band at ?3690 cm-1 for three-coordinate H 2O acting as a double-proton-acceptor/single-proton-donor in the n = 11 cluster. In contrast, the intensity of the absorption band of two-coordinate H2O acting as a single-proton-acceptor/single-proton-donor at ?3715 cm -1 decreases with cluster size, and that of one-coordinate H2O acting as a single-proton-acceptor at ?3740 and ?3650 cm-1 diminishes nearly entirely at n > 10 in the spectrum. To deduce the information about cluster temperature, we measured the spontaneous dissociation rates of the cluster ions inside an octopole ion trap and fitted the measured rate constants to an empirical Arrhenius equation. Temperatures in the range of 150 K were estimated for all H+(H2O)9-11, suggesting that the thermal effect may populate the structures other than the true ground state. The results, combined with previously acquired spectra for H+(H2O)5-8 (J.-C. Jiang, Y.-S. Wang, H.-C. Chang, S. H. Lin, Y. T. Lee, G. Niedner-Schatteburg and H.-C. Chang, J. Am. Chem. Soc., 2000, 122, 1398) and Monte Carlo simulations with the OSS2 model potential (L. Ojam?c, I. Shavitt and S. J. Singer, J. Chem. Phys., 1998, 109, 5547), show a systematic change in hydrogen-bond topology from tree-like, single-ring, multiple-ring to cage-like isomers (and their mixtures) as the cluster size increases from n = 5 to n = 11. ? The Owner Societies 2005. |
URI: | https://www.scopus.com/inward/record.uri?eid=2-s2.0-15444366642&doi=10.1039%2fb412281j&partnerID=40&md5=d857b2088443cd57ca7bea0c04d646cf https://scholars.lib.ntu.edu.tw/handle/123456789/623502 |
DOI: | 10.1039/b412281j | SDG/關鍵字: | proton; water; article; dissociation; hydrogen bond; ion trap mass spectrometry; isomer; Monte Carlo method; spectroscopy; temperature; vibration; vibrational predissociation spectroscopy |
顯示於: | 化學系 |
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