CISD Configuration Interaction with

CISD configuration interaction with single and double excitations... 

CISD configuration interaction with singly and doubly excited determinants only DRE Dewar resonance energy... 

CISD Configuration interaction with singles and doubles... 

Zero-Order Wave Function Selected by Iterative Process CISD Configuration Interaction with Singles and Doubles... 

As has been demonstrated by numerous studies, the accuracy of properties calculated using the GGA DFT methods is, in most cases, comparable to or better than those from ab initio MP2 (Mpller-Plesset second-order perturbation) or CISD (configuration interaction with single and double excitations) methods. In fact, the accuracy of the DFT results in some instances matches those obtained from the much more costly (but, in principle, more exact) CCSD(T) (coupled cluster singles and doubles with a perturbative inclusion of connected triple excitations) method (29) and the ab initio G1 procedure (30). 

Practical applications of the method of configuration interaction to atoms and molecules almost invariably employ some limited expansion for the wave function. One of the most commonly used configuration interaction techniques includes all single and double excitations with respect to some single determinantal reference function. The ciSD ( Configuration Interaction with Single and Double excitations ) wave function has the form... 

Let s compare these CASSCF results with those for a method that is not size-consistent, Cl with no complete aspect. We ll use CISD (configuration interaction singles and doubles Section 5.4.3). Here are the results for CISD/6-31G ... 

The high bond stabilities in LaAu and LuAu have been studied by Schwerdtfeger and Dolg (1991) using relativistic as well as nonrelativistic ab initio PPs and correlation treatments like Moller-Plesset perturbation theory up to fourth order (MP , = 2,3,4), configuration interaction with single and double substitutions (CISD) and coupled electron... 

In table 5 we compare the results of HF, configuration interaction with singles and doubles excitations (CISD) and the two-structure GMS calculations, with the available experimental data. The results fi om the GMS calculations are always better than those from either the HF or the CISD ones, with the additional advantages of compactness of the wavefunction and exact preservation of the full symmetry of the system. 

CCSD(T) = coupled cluster configuration interaction including all singly and doubly excited configurations with perturbative inclusion of triples CISD = configuration interaction all singly and doubly excited configurations included DME = dimethyl ether NHO = natural hybrid orbital PDME = proto-nated dimethyl ether. 

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