Single-double configuration interaction

Figure 1. The shape of the potential curve for nitrogen in a correlation-consistent polarized double-zeta basis set is presented for the variational 2-RDM method as well as (a) single-reference coupled cluster, (b) multireference second-order perturbation theory (MRPT) and single-double configuration interaction (MRCl), and full configuration interaction (FCl) wavefunction methods. The symbol 2-RDM indicates that the potential curve was shifted by the difference between the 2-RDM and CCSD(T) energies at equilibrium.

MP (n = 2-4) n-th order of Mpller-Plesset correlation energy correction MRSDCI multireference single - - double configuration interaction... 

In this work we are concerned with the dressing method known as Size-Consistent Self-consistent Singles and Doubles Configuration Interaction, usually abbrebiated to (SC) SDCI [8]. This method can be considered as a generalization of the CEPA-3 formalism, as has been shown elsewhere [8,35]. It provides size-extensive roots and... 

Another class of methods uses more than one Slater determinant as the reference wave function. The methods used to describe electron correlation within these calculations are similar in some ways to the methods listed above. These methods include multiconfigurational self-consistent field (MCSCF), multireference single and double configuration interaction (MRDCI), and /V-clcctron valence state perturbation theory (NEVPT) methods.5... 

Coupled-cluster singles and doubles Configuration-interaction Configuration-interaction singles... 

B3LYP Three-parameter hybrid density functional method the MCPF method is an extension of the singles and doubles configuration interaction approach D95- " - is a Dunning double-zeta plus polarization and diffuse functions quality basis set D95 is the D95- " - basis set in which basis set functions and the polarization functions on the hydrogen atoms have not been included. 

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... 

Multireference Briliouin-Wigner cou/ded cluster singles and doubles (MRBWCCSDJ and multireference doubles configuration interaction (MRD-CI) calculations for the Bergman cyclization reaction... 

Chwee TS, Szilva AB, Lindh R, Carter EA (2008) Linear scaling multireference singles and doubles configuration interaction. J Chem Phys 128 224106-1/9... 

H + CH2 CH3 This reaction has been the subject of several experimental [11] and theoretical studies [12]. The published theoretical work calculated portions of the hindered rotation barriers for different values of Rh-C Ihe distance of the attacking H from CH2. This calculation employed a tzp basis set [13] with an multireference singles and doubles configuration interaction (MRSDCI) wavefunction and was carried out with the COLUMBUS program system [14]. This work has now been supplemented by a much more extensive mapping of the hindered rotational potential with a less expensive dzp basis set [13], Tests show that Vtr is not sensitive to dzp or tzp basis set selection. 

To check the influence of correlation energy on the analysis performed, single reference configuration interaction calculations [hereafter referred to as Single plus Double Configuration Interaction (SDCI)] have been carried out on the compound Fe CO)i 7i -CH2O), by using the direct-CI method [3]. 58 electrons have been frozen because of the dimensions... 

The basis set convergence error is separate from the accuracy of the particular electronic structure method used to solve the Schrodinger equation (Hartree-Fock, singles and doubles configuration interaction, second-order perturbation theory, etc.). The methods error is defined by... 

CSF = configurational spin functions GUGA = graphical unitary group approach MRSDCl = multireference singles and doubles configuration interaction RCl = relativistic Cl RECP = relativistic effective core potential. 

CCSD(T) = coupled-cluster approach for singles and doubles and connected triples CPF = coupled-pair functional CSOV = constrained space orbital variation SDCI = singles and doubles configuration interaction. 

CISD single-reference configuration interaction with single and double replacements... 

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