Short-time charge motion in Hen+ clusters
Short-time charge motion in Hen+ clusters
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DOI：
10.1063/1.477784
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发表时间：
1998-12-22
影响因子：
4.4
通讯作者：
Spiegelmann, F
中科院分区：
文献类型：
--
作者：
Seong, J;Janda, KC;Spiegelmann, F
本文用含时波包方法研究了He-n（+）团簇（n = 3，14，40和112）的电荷短时离域机制.一个DIM（分子中的化合物）的潜力是用来计算电子本征值和本征向量的正电荷团簇，并创建一个相干叠加态最初本地化的电荷在一个原子上。然后通过传播初始波函数200 fs来计算作为时间函数的电荷分布，在此期间将发生很少的核运动。电荷运动分为三类。对于团簇中相对孤立的原子的初始电离，电荷仅与其他原子弱耦合，并且在200 fs内几乎没有电荷运动。对于两个或三个原子耦合但与簇的其余部分隔离的初始位置，电荷在这些原子之间共振。对于超过三个原子耦合的初始电离位置，电荷可以有效地在簇的该部分上离域。对于前两种类型的位置，这往往发生在表面附近的集群，He-2（+）很可能会形成和集群将碎片之前，可以发生显着的电荷迁移。电荷离域倾向于发生在第三种类型的位置在集群的核心的初始电离。对于导致电荷离域的初始位置，离域的距离和方向被表征（C）1998美国物理研究所。[S0021-9606（98）00848-4]。
The mechanism of short-time charge delocalization in He-n(+) clusters, n = 3, 14, 40, and 112, is studied using time-dependent wave packets for the electronic states for fixed nuclear positions chosen randomly from quantum Monte Carlo distributions for the neutral clusters. A DIM (diatomics-in-molecules) potential is used to calculate electronic eigenvalues and eigenvectors for the positively charged clusters, and a coherent superposition of states is created to initially localize the charge on a single atom. The charge distribution as a function of time is then calculated by propagating the initial wave function for 200 fs, during which little nuclear motion will occur. The charge motion is separated into three categories. For initial ionization of relatively isolated atoms in the cluster, the charge is only weakly coupled to other atoms, and there is little charge motion in 200 fs. For initial positions at which two or three atoms are coupled, but isolated from the rest of the cluster, the charge resonates among these atoms. For initial ionization positions at which more than three atoms are coupled, the charge can effectively delocalize over that part of the cluster. For the first two types of positions, which tend to occur near the surface of the cluster, He-2(+) is likely to form and the cluster will fragment before significant charge migration can occur. Charge delocalization tends to occur for initial ionization at the third type of location in the core of the cluster. For the initial positions that lead to charge delocalization, the distance and direction of the delocalization was characterized (C) 1998 American Institute of Physics. [S0021-9606(98)00848-4].