Configuration interaction singly excited configurations

The excited-state dynamics of these complex molecules have also been studied by ultrafast time-resolved spectroscopy " to elucidate the mechanistic details. The potential energy (PE) function of the first excited singlet state of the ESIPT process in salicylic acid has been calculated by ab initio MO calculations using the 6-3IG basis set at the restricted Hartree—Fock and configuration interaction single excitation (CIS) levels, as well as the semi-empitical method... 

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... 

A number of methods have been proposed for calculations of the geometries of molecules in excited states. These include CIS (Configuration Interaction Singles) and variations on CIS to account for the effect of double substitutions, as well as so-called time dependent density functional models. Except for CIS (the simplest of the methods) there is very little practical experience. There is also very little solid experimental data on the geometries of excited-state molecules. 

CIS Model. Configuration Interactions Singles. A limited Configuration Interaction scheme in which only single excitations from occupied to unoccupied molecular orbitals are considered. This is perhaps the simplest method available to the description of Excited States of molecules. 

Use the zero differential overlap (ZDO) approximation for the two-electron integrals to show that the singly excited configurations and transition dipoles are equal. When they are allowed to interact two states are formed ... 

The Brillouin theorem states that if FHF represents a closed-shell molecule, then singly excited configurations such as Wt do not interact with /HF, i.e. < /HF IPj) = 0 and thus Cj = 0. Hence equation (14) becomes... 

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... 

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