Borgis Daniel, Rossky Peter J, Turi László
Pôle de Chimie Théorique, UMR-CNRS PASTEUR, Ecole Normale Supérieure, 24, rue Lhomond, 75231 Paris Cedex 05, France.
Department of Chemistry, Rice University , P.O. Box 1892, MS-60, Houston, Texas 77251-1892, United States.
J Phys Chem Lett. 2017 May 18;8(10):2304-2309. doi: 10.1021/acs.jpclett.7b00555. Epub 2017 May 10.
An ongoing controversy about water cluster anions concerns the electron-binding motif, whether the charge center is localized at the surface or within the cluster interior. Here, mixed quantum-classical dynamics simulations have been carried out for a wide range of cluster sizes (n ≤ 1000) for (HO) and (DO), based on a nonequilibrium first-order rate constant approach. The computed data are in good general agreement with time-resolved photoelectron imaging results (n ≤ 200). The analysis reveals that, for surface state electrons, the cluster size dependence of the excited state electronic energy gap and the magnitude of the nonadiabatic couplings have compensating influences on the excited state lifetimes: the excited state lifetime for surface states reaches a minimum for n ∼ 150 and then increases for larger clusters. It is concluded that the electron resides in a surface-localized motif in all of these measured clusters, dominating at least up to n = 200.
关于水簇阴离子的一个持续争议涉及电子结合模式，即电荷中心是位于表面还是在簇内部。在此，基于非平衡一级速率常数方法，对一系列不同尺寸（n≤1000）的（HO）和（DO）簇进行了混合量子 - 经典动力学模拟。计算数据与时间分辨光电子成像结果（n≤200）总体上吻合良好。分析表明，对于表面态电子，激发态电子能隙的簇尺寸依赖性和非绝热耦合的大小对激发态寿命有补偿作用：表面态的激发态寿命在n ∼ 150时达到最小值，然后对于更大的簇会增加。得出的结论是，在所有这些测量的簇中，电子存在于表面局域化模式中，至少在n = 200之前占主导地位。
