Single reference configuration

On the other hand, DFT calculations, especially with the B3LYP functional, frequently do give results that are as good as those obtained from CCSD(T). The latter is currently the gold standard level of theory for wave function based calculations that employ a single reference configuration. 

The above described order parameters are effective for the native state. How about the unfolded or denatured state It is much harder to characterize this state, as there is not a single reference configuration to compare to. One would like to use a nonspecific order parameter, such as the radius of gyration Rg. This parameter, often used for polymers, is defined as [54]... 

The SDCI + Q method based on a single-reference configuration underestimates the dissociation energies uniformly as seen from table 51. This is expected in view of a... 

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... 

CISD from a single reference configuration can be performed not only with UHF and ROHF MOs, but also with CASSCF MOs. Because the MOs outside the active space have been optimized for the full Cl within the active space in a CAS calculation, CASSCF MOs often give the lowest CISD energies. 

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

The FCI wave function is often dominated by a single reference configuration, usually the Hartree-Fock state. It is then convenient to think of the FCI wave function as generated from this reference configuration by the application of a linear combination of spin-orbital excitation operators... 

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