TD-CI simulation of the electronic optical response of molecules in intense fields: comparison of RPA, CIS, CIS(D), and EOM-CCSD.
TD-CI simulation of the electronic optical response of molecules in intense fields: comparison of RPA, CIS, CIS(D), and EOM-CCSD.
复制标题
强场中分子电子光学响应的 TD-CI 模拟：RPA、CIS、CIS(D) 和 EOM-CCSD 的比较。
DOI：
10.1021/jp107384p
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Schlegel,HBernhard
中科院分区：
文献类型：
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作者：
Sonk,JasonA;Caricato,Marco;Schlegel,HBernhard
许多不同层次的理论已被测试在TD-CI模拟丁二烯与非常短的，强激光脉冲相互作用的响应。激发能和跃迁偶极子计算与线性响应时间相关的Hartree-Fock（也称为随机相位近似，RPA）、单激发空间中的组态相互作用（CIS）、涉及双激发的CIS的微扰校正[CIS（D）]，以及使用6- 31 G（d，p）基组扩充n = 0−3组在所有碳上和仅在末端碳上的扩散sp函数[分别为6- 31 n + G（d，p）和6-31（n+）G（d，p）]。扩散函数对于高于电离阈值的伪连续态之间的跃迁特别重要。模拟采用三周期高斯脉冲（ω = 0.06 Au，760 nm），强度高达1.26 × 1014 W cm− 2，方向沿着连接末端碳的矢量。根据基础设置，模拟需要多达500个激发态。在选定的条件下，6- 31 G（d，p）基组的响应太弱，理论水平之间的差异更明显。当在所有碳上包括两组或三组扩散函数时，RPA、CIS和EOM-CC结果是相当的，但是与更精确的EOM-CC计算相比，CIS（D）响应太大。即使脉冲的频率与任何基态到激发态的跃迁都不共振，但在强度高于阈值的情况下，很容易发生到价态和伪连续态的激发。
A number of different levels of theory have been tested in TD-CI simulations of the response of butadiene interacting with very short, intense laser pulses. Excitation energies and transition dipoles were calculated with linear-response time-dependent Hartree−Fock (also known as the random phase approximation, RPA), configuration interaction in the space of single excitations (CIS), perturbative corrections to CIS involving double excitations [CIS(D)], and the equation-of-motion coupled-cluster (EOM-CC) method using the 6-31G(d,p) basis set augmented withn= 0−3 sets of diffuse sp functions on all carbons and only on the end carbons [6-31n+ G(d,p) and 6-31(n+)G(d,p), respectively]. Diffuse functions are particularly important for transitions between the pseudocontinuum states above the ionization threshold. Simulations were carried out with a three-cycle Gaussian pulse (ω = 0.06 au, 760 nm) with intensities up to 1.26 × 1014W cm−2directed along the vector connecting the end carbons. Depending on the basis set, up to 500 excited states were needed for the simulations. Under the conditions selected, the response was too weak with the 6-31G(d,p) basis set, and the difference between levels of theory was more pronounced. When two or three set of diffuse functions were included on all of the carbons, the RPA, CIS, and EOM-CC results were comparable, but the CIS(D) response was too large compared to the more accurate EOM-CC calculations. Even though the frequency of the pulse is not resonant with any of the ground-to-excited transitions, excitations to valence and pseudocontinuum states occur readily above a threshold in the intensity.