Picosecond IR-UV pump-probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. I. Intramolecular vibrational energy redistribution of the OH and CH stretching vibrations of bare phenol.
Picosecond IR-UV pump-probe spectroscopic study of the dynamics of the vibrational relaxation of jet-cooled phenol. I. Intramolecular vibrational energy redistribution of the OH and CH stretching vibrations of bare phenol.
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DOI：
10.1063/1.1668640
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发表时间：
2004-04
期刊：
影响因子：
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通讯作者：
Yuji Yamada;T. Ebata;M. Kayano;N. Mikami
中科院分区：
文献类型：
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作者：
Yuji Yamada;T. Ebata;M. Kayano;N. Mikami
用皮秒时间分辨红外-紫外泵浦-探测光谱研究了喷射冷却的苯酚-h6（C6 H8 OH）和苯酚-d8（C6 D8 OH）分子基态OH伸缩振动的分子内振动能量再分配（IVR）.用皮秒红外激光脉冲激发苯酚分子的OH伸缩振动，用皮秒紫外脉冲多光子电离探测，观测到初始激发态和IVR引起的重分布能级随时间的演化.苯酚-h6的OH伸缩振动的IVR寿命被确定为14 ps，而苯酚-d8的OH伸缩振动的IVR寿命被发现为80 ps。这一显着的变化的IVR速率常数时，dueteration的CH基团强烈表明，“门口状态”的IVR从OH水平将是振动态涉及CH伸缩模式。我们还研究了苯酚-h6的CH伸缩振动的IVR速率。发现CH伸缩的IVR寿命小于5 ps。快速IVR由CH伸缩与许多其他组合或泛音带的强非谐共振来描述。
The intramolecular vibrational energy redistribution (IVR) of the OH stretching vibration of jet-cooled phenol-h6 (C6H8OH) and phenol-d8 (C6D8OH) in the electronic ground state has been investigated by picosecond time-resolved IR-UV pump-probe spectroscopy. The OH stretching vibration of phenol was excited with a picosecond IR laser pulse, and the subsequent temporal evolutions of the initially excited level and the redistributed ones due to the IVR were observed by multiphoton ionization detection with a picosecond UV pulse. The IVR lifetime for the OH stretch vibration of phenol-h6 was determined to be 14 ps, while that of the OH stretch for phenol-d8 was found to be 80 ps. This remarkable change of the IVR rate constant upon the dueteration of the CH groups strongly suggests that the "doorway states" for the IVR from the OH level would be the vibrational states involving the CH stretching modes. We also investigated the IVR rate of the CH stretching vibration for phenol-h6. It was found that the IVR lifetime of the CH stretch is less than 5 ps. The fast IVR is described by the strong anharmonic resonance of the CH stretch with many other combinations or overtone bands.