论文标题
时间依赖性的优化耦合群集方法用于多电体动力学II。耦合电子对近似
Time-dependent optimized coupled-cluster method for multielectron dynamics II. A coupled electron-pair approximation
论文作者
论文摘要
我们报告了在时间依赖性优化耦合群集（TD-OCC）方法的框架内实现一种具有成本效益的近似方法[J.化学物理。 148，051101（2018）]用于实时激光驱动的多电体动力学的实时模拟。该方法被指定为TD-OCEPA0，是具有优化轨道的耦合电子对近似的最简单版本的时间相关扩展[J.化学物理。 139，054104（2013）]。与具有双重激发（TD-OCCD）的TD-OCC相比，它的尺寸广泛，规格不变，并且计算上的效率要高得多。我们采用了这种方法来模拟NE和AR原子中的电子动力学，暴露于具有各种强度的近红外激光脉冲。将计算的结果（包括高谐波生成光谱和电离产量）与从不相关的时间依赖性的Hartree-Fock（TDHF）到完全相关的（在活性轨道上）的完全依赖性的完全依赖性的完全依赖性空间自相稳定的自相稳定性（TD-CASSCF（TD-CASSCF））的其他各种方法的比较。 TD-OCEPA0结果与TD-CASSCF（对于中等激光强度）的结果达成了很好的一致性。但是，对于更高的强度，TD-OCEPA0倾向于高估相关效应，因为在基态相关能量计算中CEPA0偶尔观察到的相关效应。
We report the implementation of a cost-effective approximation method within the framework of time-dependent optimized coupled-cluster (TD-OCC) method [J. Chem. Phys. 148, 051101 (2018)] for real-time simulations of intense laser-driven multielectron dynamics. The method, designated as TD-OCEPA0, is a time-dependent extension of the simplest version of the coupled-electron pair approximation with optimized orbitals [J. Chem. Phys. 139, 054104 (2013)]. It is size extensive, gauge invariant, and computationally much more efficient than the TD-OCC with double excitations (TD-OCCD). We employed this method to simulate the electron dynamics in Ne and Ar atoms exposed to intense near infrared laser pulses with various intensities. The computed results, including high-harmonic generation spectra and ionization yields, are compared with those of various other methods ranging from uncorrelated time-dependent Hartree-Fock (TDHF) to fully-correlated (within the active orbital space) time-dependent complete-active-space self-consistent-field (TD-CASSCF). The TD-OCEPA0 results show a good agreement with TD-CASSCF ones for moderate laser intensities. For higher intensities, however, TD-OCEPA0 tends to overestimate the correlation effect, as occasionally observed for CEPA0 in the ground-state correlation energy calculations.
