Photodissociation dynamics of H2O: Effect of unstable resonances on the (B)over-tilde 1A1 electronic state
Photodissociation dynamics of H2O: Effect of unstable resonances on the (B)over-tilde 1A1 electronic state
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DOI：
10.1063/1.3554213
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发表时间：
2011-02-14
影响因子：
4.4
通讯作者：
Yang, Xueming
中科院分区：
文献类型：
--
作者：
Cheng, Yuan;Yuan, Kaijun;Yang, Xueming
利用氢原子里德伯标记技术，研究了H_2O分子在（B）~（1）A（1）电子态上的不同不稳定共振态的可调谐真空紫外光解离.测量了量子态分辨的OH产物的平动能分布和角分布。实验结果首次表明，不同的不稳定共振激发对OH（X）和OH（A）产物通道有很大不同的影响。OH（X）产物的转动分布变化很小，而OH（A）产物的转动分布和态分辨角分布随着光解能量的增加而显著变化。同时还观察到了母体转动激发对OH（A）产物的影响。通过对实验光谱的仔细模拟，确定了五个光解波长下OH（A）/OH（X）的分支比。理论和实验在分支比方面的一般一致性是好的。不同转动能级的OH（A）产物的分支比接近核自旋统计值，这也与当前实验中H2O束极低的转动温度相一致。(C)2011年美国物理学会。[doi：10.1063/1.3554213]
We report a tunable vacuum ultraviolet photodissociation study of H2O from different unstable resonances in the (B) over tilde (1)A(1) electronic state, using the H-atom Rydberg tagging technique. The quantum state resolved OH product translational energy distributions and angular distributions have been measured. Experimental results illustrate, for the first time, that excitation to the different unstable resonances has very different effect on the OH(X) and OH(A) product channels. The OH(X) product rotational distributions vary only slightly, while the OH(A) product rotational distributions and state-resolved angular distributions change dramatically as the photolysis energy increases. Effect of parent rotational excitation on the OH(A) product has also been observed. Through careful simulations to the experimental spectra, OH(A)/OH(X) branching ratios have been determined at five photolysis wavelengths. The general agreement between theory and experiment in the branching ratios is good. The branching ratios for the OH(A) product from different parent rotational levels are close to the nuclear spin-statistics value, which is also consistent with the extremely low rotational temperature of the H2O beam in the current experiment. (C) 2011 American Institute of Physics. [doi:10.1063/1.3554213]