SAC-CI method

NakatsujI H, Kuwano R, Merita H and Nakal H 1993 Dipped adcluster model and SAC-CI method applied to harpooning, chemical luminescence and electron emission in halogen chemisorption on alkali metal surface J. Mol. Catal. 82 211-28... 

The plan of this chapter is as follows. The next section briefly reviews the CC formalism for the ground state. This is necessary since the LR-CC and EOM-CC approaches start from the CC ground state description. It also introduces some notation that will be used in later sections. Next, the basics of the exact EOM-CC approach are derived, showing how an eigensystem is arrived at. After some aspects of characterizing an electronic transition, EOM-/LR-CC methods that have been developed and implemented are surveyed. The next section presents a numerical assessment of some of the main methods. Finally, a few illustrative applications are summarized. Some aspects of EOM-CC methods are discussed in Chapter 2. The symmetry-adapted cluster configuration interaction (SAC-CI) method can be related to EOM-CC methods. The SAC-CI method and several impressive applications thereof are described in Chapter 4. 

Nakatsuji H, Hasegawa J, Hada M (1996) Excited and ionized states of free base porphin studied by the symmetry adapted cluster-configuration interaction (SAC-CI) method. J Chem Phys 104 2321-2329. 

In this section, we explain the SAC-CI method and the computational program. For detailed descriptions, we refer to the original papers [13-18] and the earlier review articles [19-22],... 

The SAC/SAC-CI method is a correlated electronic-structure theory for the ground and excited states in various spin multiplicities. The SAC method belongs to the coupled-cluster theory [30, 31]. In the case of a closed-shell singlet state, the SAC wave function is written as... 

Now, the R operator is not only singlet excitations but also triplet, doublet (ionized and electron-attached), and higher-spin multiplicities. Thus, the SAC-CI method can calculate the ground and excited states in various spin-multiplicities. 

SAC-CI method was applied to calculate the electronic CD spectrum of uridine [43], Based on theoretical CD and absorption spectra, observed peaks in the experimental spectra were assigned. The rotational strength (R) in the length form [44] was calculated as imaginary part of the inner product of the electric transition dipole moment (ETDM) and magnetic transition dipole moment (MTDM). 

Table 4-2. Singlet excited states of uridine calculated by the SAC-CI method...

SAC-CI Method Theoretical Aspects and Some Recent Topics (H. Nakatsuji)... 

H. Nakatsuji, SAC-CI method Theoretical aspects and some recent topics, in J. LeszczynsM (Ed.), Computational chemistry Reviews of current trends, Vol. 2, World Scientific Publishing, Singapore, 1977, pp. 62-124, Chapter 2. 

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