Picosecond IR–UV pump–probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. II. Intracluster vibrational energy redistribution of the OH stretching vibration of hydrogen-bonded clusters

Journal of Chemical Physics 120 巻 16 号 7410-7417 頁 2004-04-22 発行
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タイトル ( eng )
Picosecond IR–UV pump–probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. II. Intracluster vibrational energy redistribution of the OH stretching vibration of hydrogen-bonded clusters
作成者
Kayano Masakazu
Yamada Yuji
Mikami Naohiko
収録物名
Journal of Chemical Physics
120
16
開始ページ 7410
終了ページ 7417
抄録
A picosecond time-resolved IR–UV pump–probe spectroscopic study has been carried out for investigating the intracluster vibrational energy redistribution (IVR) and subsequent dissociation of hydrogen-bonded clusters of phenol (C6H5OH) and partially deuterated phenol (C6D5OH, phenold5) with various solvent molecules. The H-bonded OH stretching vibration was pumped by a picosecond IR pulse, and the transient S1– S0 UV spectra from the pumped level as well as the redistributed levels were observed with a picosecond UV laser. Two types of hydrogen-bonded clusters were investigated with respect to the effect of the H-bonding strength on the energy flow process: the first is of a strong "s-type H-bond" such as phenol-(dimethyl ether)n=1 and phenol dimer, and the second is phenol-(ethylene)n=1 having a weak "p-type H-bond." It was found that the population of the IR-pumped OH level exhibits a single-exponential decay, whose rate increases with the H-bond strength. On the other hand, the transient UV spectrum due to the redistributed levels showed a different time evolutions at different monitoring UV frequency. From an analysis of the time profiles of the transient UV spectra, the following three-step scheme has been proposed for describing the energy flow starting from the IVR of the initially excited H-bonded OH stretching level to the dissociation of the H bond. (1) The intramolecular vibrational energy redistribution takes place within the phenolic site, preparing a hot phenol. (2) The energy flows from the hot phenol to the intermolecular vibrational modes of the cluster. (3) Finally, the hydrogen bond dissociates. Among the three steps, the rate constant of the first step was strongly dependent on the H-bond strength, while the rate constants of the other two steps were almost independent of the H-bond strength. For the dissociation of the hydrogen bond, the observed rate constants were compared with those calculated by the Rice, Ramsperger, Kassel, and Marcus model. The result suggests that dissociation of
言語
英語
資源タイプ 学術雑誌論文
出版者
American Institute of Physics
発行日 2004-04-22
権利情報
Copyright (c) 2004 American Institute of Physics.
出版タイプ Version of Record(出版社版。早期公開を含む)
アクセス権 オープンアクセス
収録物識別子
[ISSN] 0021-9606
[DOI] 10.1063/1.1668641
[NCID] AA00694991
[DOI] http://dx.doi.org/10.1063/1.1668641