Hydrogen transfer dynamics in a photoexcited phenol/ammonia (1:3) cluster studied by picosecond time-resolved UV-IR-UV ion dip spectroscopy
Hydrogen transfer dynamics in a photoexcited phenol/ammonia (1:3) cluster studied by picosecond time-resolved UV-IR-UV ion dip spectroscopy
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DOI：
10.1063/1.2806182
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发表时间：
2007-12-21
影响因子：
4.4
通讯作者：
Fujii, Masaaki
中科院分区：
文献类型：
--
作者：
Ishiuchi, Shun-ichi;Sakai, Makoto;Fujii, Masaaki
采用紫外-红外-紫外离子浸渍光谱法测量了苯酚/氨（1：3）团簇的皮秒时间分辨红外光谱。观察了激发态氢转移反应产物的时间分辨红外光谱。从3180和3250 cm（-1）两个振动带的不同时间演化，发现氢化氨自由基团簇中心点NH_4（NH_3）（2）的两种异构体共存于反应产物中。在近红外区也测量了时间演化，对应于中心点NH_4（NH_3）（2）的3 p-3s Rydberg跃迁;结果表明：（1）母体团簇存在记忆效应，它最初形成一个亚稳态产物，中心点NH 4-NH 3-NH 3，亚稳产物依次异构化为最稳定的产物NH 3-中心点NH 4-NH 3。OH裂解的时间常数，异构化，其逆反应的速率方程分析确定为24，6，和9 ps，分别。
The picosecond time-resolved IR spectra of phenol/ammonia (1:3) cluster were measured by UV-IR-UV ion dip spectroscopy. The time-resolved IR spectra of the reaction products of the excited state hydrogen transfer were observed. From the different time evolution of two vibrational bands at 3180 and 3250 cm(-1), it was found that two isomers of hydrogenated ammonia radical cluster center dot NH4(NH3)(2) coexist in the reaction products. The time evolution was also measured in the near-IR region, which corresponds to 3p-3s Rydberg transition of center dot NH4(NH3)(2); a clear wavelength dependence was found. From the observed results, we concluded that (1) there is a memory effect of the parent cluster, which initially forms a metastable product, center dot NH4-NH3-NH3, and (2) the metastable product isomerizes successively to the most stable product, NH3-center dot NH4-NH3. The time constant for OH cleaving, the isomerization, and its back reaction were determined by rate-equation analysis to be 24, 6, and 9 ps, respectively.