Hatree-Fock theory

Permethylated and partially pentylated CF6 have been used as chiral selectors for gas chromatography (GC) [47]. The geometry of these chiral selectors was optimized using Hatree-Fock theory calculations at the 6-3Ig level. Computational... 

If we understand FM or magnetic properties of quark matter more deeply, we must proceeds to a self-consistent approach, like Hartree-Fock theory, beyond the previous perturbative argument. In ref. [11] we have described how the axial-vector mean field (AV) and the tensor one appear as a consequence of the Fierz transformation within the relativistic mean-field theory for nuclear matter, which is one of the nonperturbative frameworks in many-body theories and corresponds to the Hatree-Fock approximation. We also demonstrated... 

Each vibrational mode was assigned to one of the six types of motion predicted by theoretical analysis (C=0, stretch, N-C stretch, N-Cl stretch, N-C-N bend, N-Cl bend, and C=0 bend). The vibrational frequencies of 1,3-dichloro-l,3-diazetidine-2,4-dione 45 were calculated at Hatree-Fock level, DFT (B3LYP) level, and MP-2 level of theory using a standard 6-311G basis set. For N-C stretching modes all operators except E have a trace of zero. 

In the case of the TA and DA molecules all stable conformers obtained from semiempirical methods have been examined at RHF/3-21G level. For TMDA, due to limited computer resources, we have had to limit the number of starting geometries and we have selected several conformers of the lowest energy. (Gawrohski et al., 1997) These structures have been examined at 3-21G basis set. After having obtained the results for the TA, DA and TMDA at RHF/3-21G level we have fully reoptimised the geometries with the use of the restricted Hatree-Fock method at another commonly used basis set 6-3IG. Finally we have performed calculations at MP2/6-31G //RHF/6-31G level of theory. 

Multiresolution Quantum Chemistry in Multiwavelet Bases Analytic Derivatives for Hatree-Fock and Density Functional Theory. 

All quantum chemical calculations are based on the self-consistent field (SCF) method of Hatree and Fock (1928-1930) and the MO theory of Hund, Lennard-Jones, and Mulliken (1927-1929). A method of obtaining SCF orbitals for closed shell systems was developed independently by Roothaan and Hall in 1951. In solving the so-called Roothan equations, ab initio calculations, in contrast to semiempirical treatments, do not use experimental data other than the values of the fundamental physical constants. 

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