Configuration Moller-Plesset studies

Nobes, Pople, Radotn, Handy and Knowles have studied the convergence of the Moller-Plesset orders in some detail. They computed the energies of hydrogen cyanide, cyanide anion and cyano radical through order 24 as well as at the full Configuration Interaction level. Here are some of their results ... 

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... 

Although a wide variety of theoretical methods is available to study weak noncovalent interactions such as hydrogen bonding or dispersion forces between molecules (and/or atoms), this chapter focuses on size consistent electronic structure techniques likely to be employed by researchers new to the field of computational chemistry. Not stuprisingly, the list of popular electronic structure techniques includes the self-consistent field (SCF) Hartree-Fock method as well as popular implementations of density functional theory (DFT). However, correlated wave function theory (WFT) methods are often required to obtain accmate structures and energetics for weakly bound clusters, and the most useful of these WFT techniques tend to be based on many-body perturbation theory (MBPT) (specifically, Moller-Plesset perturbation theory), quadratic configuration interaction (QCI) theory, and coupled-cluster (CC) theory. 

The equilibrium NH bond distance re(NH) = 1.038 to 1.043 A [18, 27 to 29] was calculated in ab initio studies at the MP2 (second-order Moller-Plesset perturbation theory) [27, 29], single-double Cl (configuration interaction) [18], and CASSCF (complete active space SCF) [28] levels. 

Computational restricted Hartree-Fock (RHF) and configuration integration-singles-second-order Moller-Plesset (CIS-MP2) studies by Douhal et al. [86, 92] indicated the existence of two transition states along the proton transfer pathway in doubly H-bonded 7AI dimer, so that the stepwise mechanism of proton transfer was suggested. These results have, however, been questioned and reanalyzed by Catalan and coworkers [84], as shown in Figure 3.19c. These authors have also considered a double proton transfer, but occurring in the centrosymmetric (C2h) H-bonded dimer of 7AI. They have found no indication of an intermediate... 

A recent Monte Carlo study of structure of the dilute aqueous solution of methane from this Laboratory involves one methane molecule and 124 water molecules at 25°C at liquid water density. The configurational energy of the system is developed under the assumption of pairwise additivity using potential functions representative of initio quantum mechanical calculations for both the water-water and methane-water interactions. For the water-water interaction we have carried over the MCY-CI potential function used in our previous study of the structure of liquid water reviewed in the preceeding section. For the methane water interaction energy, we have recently reported an analytical potential function representative of quantum mechanical calculations based on SCF calculations and a 6-31G basis set, with correlation effects Included via second order Moller-Plesset (MP) corrections,52 This function was used for the methane-water con-... 

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