CALCULATION OF SIZE-INTENSIVE TRANSITION MOMENTS FROM THE COUPLED CLUSTER SINGLES AND DOUBLES LINEAR-RESPONSE FUNCTION
CALCULATION OF SIZE-INTENSIVE TRANSITION MOMENTS FROM THE COUPLED CLUSTER SINGLES AND DOUBLES LINEAR-RESPONSE FUNCTION
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DOI：
10.1063/1.466321
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发表时间：
1994-03-15
影响因子：
4.4
通讯作者：
JORGENSEN, P
中科院分区：
文献类型：
--
作者：
KOCH, H;KOBAYASHI, R;JORGENSEN, P
对LiH、CH+和C-4中最低激发的激发能和偶极子跃迁强度进行了耦合团簇单双线性响应（CCLR）计算，并将结果与运动方程耦合团簇（EOMCC）的类ci方法的结果进行了比较。对于小系统的单分子计算，两种方法的跃迁强度相似。然而，CCLR方法给出了大小密集的偶极子跃迁强度，而EOMCC形式主义则没有。因此，EOMCC计算可以给出非物理的偶极子跃迁强度，例如，在对一系列非相互作用LiH系统的EOMCC计算中，我们得到了19个或更多非相互作用LiH系统的最低完全对称偶极子允许跃迁的负偶极子强度。CCLR方法被证明是一种非常有吸引力的计算过渡矩的“黑盒”方法。
Coupled cluster singles and doubles linear response (CCLR) calculations have been carried out for excitation energies and dipole transition strengths for the lowest excitations-in LiH, CH+, and C-4 and the results compared with the results from a CI-like approach to equation of motion coupled cluster (EOMCC). The transition strengths are similar in the two approaches for single molecule calculations on small systems. However, the CCLR approach gives size-intensive dipole transition strengths, while the EOMCC formalism does not. Thus, EOMCC calculations can give unphysically dipole transition strengths, e.g., in EOMCC calculations on a sequence of noninteracting LiH systems we obtained a negative dipole strength for the lowest totally symmetric dipole allowed transition for 19 or more noninteracting LiH systems. The CCLR approach is shown to be a very attractive ''black box'' approach for the calculation of transition moments.