Hydrogen molecule correlation energy

Hydrogen molecule, carbon oxide intramolecular energy, 110 clathrates, 12, 20 correlated wave function, 300... 

In the calculations of the energy of hydration of metal complexes in the inner coordination sphere, one must consider hydrogen bond formation between the first-shell water molecules and those in bulk water, which leads to chains of hydrogen-bonded water molecules. Such hydrogen-bonded chains of ethanol molecules attached to the central metal ion have been found as a result of DFT B3LYP calculations on ethanol adducts to nickel acetylacetonate, where the calculated energy of hydrogen bonds correlated well with experimental data [90]. 

Distributed Gaussian basis sets in correlation energy studies the second order correlation energy for the ground state of the hydrogen molecule... 

The aim of this paper is ascertain whether it is possible to determine the ground state second-order correlation energy of the hydrogen molecule to sub-millihartree accuracy using a basis set containing only s-type Gaussian functions with exponents and distribution determined by an empirical, but physically motivated, procedure. 

It has been shown that the second order electron correlation energy for the ground state of the hydrogen molecule at its equilibriiun nuclear geometry can be described to an accmacy below the sub-milliHartree level using a distributed basis set of Gaussian basis subsets containing only s-type functions only. Each of the basis subsets are taken to be even-tempered sets. The distribution of the subsets is empirical but nevertheless physically motivated. 

When we look at the energies from Table 15. 10, perhaps the most striking fact is that the correlation energy in the n system makes so little difference in the Ai values. As we indicated above, the experimental value for the resonance energy from heats of hydrogenation is —1.54 eV, in quite satisfactory agreement with the result in Table 15.10. The fact that our value is a little lower than the experimental one may be attributed to the small amoimt of residual resonance remaining in the cyclohexatriene, whereas the isolated double bonds in the experiment are truly isolated in separate molecules. ... 

Fig. 3.9 Left-hand panel The overlap / electrostatic , exchange-correlation and bond integral 2ssa contributions to the binding energy of the hydrogen molecule (where ssa = h). Right-hand panel The binding energy curve (full line) is the sum of the three contributions , 2ssa and (see text for details). (After Skinner and Pettifor (1991).)...

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