Simulating the absorption spectra of helium clusters (N = 70, 150, 231, 300) using a charge transfer correction to superposition of fragment single excitations.
Simulating the absorption spectra of helium clusters (N = 70, 150, 231, 300) using a charge transfer correction to superposition of fragment single excitations.
复制标题
使用电荷转移校正来叠加片段单激发来模拟氦簇 (N = 70、150、231、300) 的吸收光谱。
DOI：
10.1063/1.4973611
复制
发表时间：
2017
期刊：
影响因子：
--
通讯作者：
M. Head‐Gordon
中科院分区：
文献类型：
--
作者：
Qinghui Ge;Yuezhi Mao;Alec F. White;E. Epifanovsky;K. D. Closser;M. Head‐Gordon
用路径积分分子动力学方法模拟了HEN(N = 70，15 0，2 31，30 0)团簇的n = 2吸收光谱.用Almo-CIS+CT方法处理电子结构，这是一种基于绝对定域分子轨道(ALMO)的组态相互作用单(CIS)公式。该方法推广了先前报道的Almo-CIS模型[K.D.Closser等人。J·化学。理论计算。11,5791(2015)]以包括空间局域电荷转移(CT)效应。它被设计用来恢复原子和分子团簇中的大量激发态，例如氦团簇中的整个n = 2里德堡带。结果表明，Almo-CIS+CT能很好地弥补由于忽略电荷转移而产生的大部分误差，对氦团簇的计算精度与标准CIS相当。对于n = 2频段，CT将状态稳定在蓝边，最高可达0.5eV。Almo-CIS+CT保留了Almo-CIS关于系统大小的形式立方标度。通过对最初报告的Almo-CIS的实现进行改进，Almo-CIS+CT能够使用少量的计算资源来处理含有数百个原子的氦原子团簇。用路径积分分子动力学和球面边界条件模拟了300个氦原子团簇的2s和2p带的吸收光谱，得到了3K时的原子组态，再现了实验报道的氦团簇荧光激发光谱的主要特征。
Simulations of the n = 2 absorption spectra of HeN (N = 70, 150, 231, 300) clusters are reported, with nuclear configurations sampled by path integral molecular dynamics. The electronic structure is treated by a new approach, ALMO-CIS+CT, which is a formulation of configuration interaction singles (CIS) based on absolutely localized molecular orbitals (ALMOs). The method generalizes the previously reported ALMO-CIS model [K. D. Closser et al. J. Chem. Theory Comput. 11, 5791 (2015)] to include spatially localized charge transfer (CT) effects. It is designed to recover large numbers of excited states in atomic and molecular clusters, such as the entire n = 2 Rydberg band in helium clusters. ALMO-CIS+CT is shown to recover most of the error caused by neglecting charge transfer in ALMO-CIS and has comparable accuracy to standard CIS for helium clusters. For the n = 2 band, CT stabilizes states towards the blue edge by up to 0.5 eV. ALMO-CIS+CT retains the formal cubic scaling of ALMO-CIS with respect to system size. With improvements to the implementation over that originally reported for ALMO-CIS, ALMO-CIS+CT is able to treat helium clusters with hundreds of atoms using modest computing resources. A detailed simulation of the absorption spectra associated with the 2s and 2p bands of helium clusters up to 300 atoms is reported, using path integral molecular dynamics with a spherical boundary condition to generate atomic configurations at 3 K. The main features of experimentally reported fluorescence excitation spectra for helium clusters are reproduced.