Striking Isotopologue-Dependent Photodissociation Dynamics of Water Molecules: The Signature of an Accidental Resonance
Striking Isotopologue-Dependent Photodissociation Dynamics of Water Molecules: The Signature of an Accidental Resonance
复制标题
水分子的惊人的同位素依赖性光解离动力学：意外共振的特征
DOI：
10.1021/acs.jpclett.9b01710
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发表时间：
2019-08-01
影响因子：
5.7
通讯作者：
Yang, Xueming
中科院分区：
文献类型：
--
作者：
Chang, Yao;Chen, Zhichao;Yang, Xueming
调查的光致碎裂模式的轻水和重水在状态到状态的水平是一个先决条件的化学处理和同位素异质性的星际介质中的任何彻底的理解。在这里，我们使用可调真空紫外源结合高分辨率H（D）原子里德堡标记飞行时间技术，揭示了水分子激发到波浪线（010）态（C）后解离的动力学特征。H_2O和D_2O生成H（D）原子的作用谱和激发到（C）~（010）态的OH（OD）产物态分布都显示出显著的差异，这归因于同位素特异性的偶然共振效应。这种偶然共振引起的状态混合可能有助于在太阳系中的D/H同位素的不均匀性。目前的研究提供了一个很好的例子，竞争状态到状态的非绝热衰变途径涉及至少五个电子状态。
Investigations of the photofragmentation patterns of both light and heavy water at the state-to-state level are a prerequisite for any thorough understanding of chemical processing and isotope heterogeneity in the interstellar medium. Here we reveal dynamical features of the dissociation of water molecules following excitation to the (C) over tilde (010) state using a tunable vacuum ultraviolet source in combination with the high-resolution H(D)-atom Rydberg tagging time-of-flight technique. The action spectra for forming H(D) atoms and the OH(OD) product state distributions resulting from excitation to the (C) over tilde (010) states of H2O and D2O both show striking differences, which are attributable to the effects of an isotopologue-specific accidental resonance. Such accidental-resonance-induced state mixing may contribute to the D/H isotope heterogeneity in the solar system. The present study provides an excellent example of competitive state-to-state nonadiabatic decay pathways involving at least five electronic states.