Single excitation configuration interactions

A single-excitation configuration interaction (CIS) calculation is probably the most common way to obtain excited-state energies. This is because it is one of the easiest calculations to perform. 

Head-Gordon M, Oumi M, Maurice D (1999) Quasidegenerate second-order perturbation corrections to single-excitation configuration interaction. Mol Phys 96 593... 

The spectroscopic properties of [Pt(2,2, 6, 2-terpyridine)(C=CR)]+ (R=H, CH2OH, and C6H5) (5.6) were theoretically studied by Zhang et al. [101], The second-order Mpller-Plesset perturbation (MP2) was used to optimize the ground state and the single-excitation configuration interaction (CIS) method was employed to obtain the excited-state structure. The spectroscopic properties of the... 

Combination of DFT and single excitation configuration interaction approach (DFT/ SCI) Theoretical calculation of CD spectrum, i.e., excitation energies AE and rotatory strengths R 1999TA3483... 

MRINDO/S calculations of electronic spectra of triazines and tetrazines, completed by singly excited configuration interaction, revealed the importance of the outer (Rydberg) atomic orbitals <2000THAC434>. According to the calculations, n-to-Jt" transitions do not show any intensity. 

A common truncation is to use single excitation configuration interaction (SCI) results for p and single and double excitation Cl (SDCI) results for 7. The... 

We start by expressing the excited-state electronic wavefunction for state / as a singly excited configuration interaction wavefunction (CIS)... 

Two other types of basis set that have been used successfully in hfs calculations are Chipman s contracted [3s,2p] bases, and basis sets based on Slater type orbitals (STOs). The former of these is mainly used in single excitation configuration interaction (CIS) calculations, and are based on a very fortuitous cancellation of errors between method and basis set. The performance of the CIS/[3s,2p] approach lies within 20-25% of experiment. One should recall, though, that once we go to larger molecular systems, the CIS method becomes computationally very demanding, STOs have mainly been used in semiempirical INDO hfcc calculations (STO-SG) and in the density functional theory (DFT) studies of Ishii and Shimitzu (STO-6G). The number of hfcc studies using these basis sets at the ab initio or DFT levels is however to date very limited. 

High accuracy energies via automated G1, G2, G2(MP2), CBS-4, CBS-q, CBS-Q, and CBS-APNO methods. Excited state energies using single-excitation configuration interaction (Cl-Singles). 

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