According to the definition in the text, the correlation energy of 1s2C of carbon atoms, the primary and secondary C-H bonding electron pairs in some CH3, CH2 fragments and CH3(CH2)mCH3 (m=1-5) linear alkane molecules are calculated and analyzed. The transferability of the correlation energies of these electron pairs in the linear alkanes is investigated. The results indicate that the correlation energy of 1s2C is perfectly transferable in the respective methyl and methylene groups, while the correlation energies of the primary and secondary C-H bonding electron pairs are approximately transferable in methyl and methylene groups. The analysis of the results of group correlation energy shows that both of the correlation energies of methyl and methylene groups are transferable in these linear alkanes. The correlation energies of methylene group in CH3(CH2)mCH3 (m=1-5) molecules are slightly decreasing showing a converging trend to a "standard" methylene group in linear alkanes. The excellent fitting relationship between the total correlation energy and the number of methylene groups of the linear alkanes shows that the total correlation energy is a linear function of the number of methylene groups, which means that the total correlation energies of large linear alkanes can be reproduced and predicted by counting the numbers of methylene groups. In this way, total correlation energy of large linear alkane molecule can be approximately calculated using this simple group additive scheme with substantial saving in computational time.

Cadmium(II) imidazolate (3), with a twofold interpenetrating diamondoid net, was obtained in a manner similar to cobalt(II) imidazolate. In the process, a crystallized intermediate involving piperazine (2), which was suitable for X-ray single crystal study, was isolated. Based on the composition of 2, a mechanism for the solvothermal synthesis of metal imidazolates was proposed. 3: a = 9.931(2), b = 10.739(2), c =

Articles you may be interested inHow accurate is the strongly orthogonal geminal theory in predicting excitation energies? Comparison of the extended random phase approximation and the linear response theory approaches Accurate ab initio potential energy curve of F 2 . I. Nonrelativistic full valence configuration interaction energies using the correlation energy extrapolation by intrinsic scaling method Electron pair correlation contribution from individual electron pairs of the molecular orbitals is defined and used in analyzing the correlation patterns of F 2 , O 2 2Ϫ , and CH 3 CH 3 isoelectronic covalent systems. Based on our simple strategy so-called ''separating large system into smaller ones'' for estimating the correlation energies by investigating both the ionic and the diradical partitioning schemes for covalent systems, a simple scaling scheme is presented for estimating the total correlation energy. It is achieved by summing the scaled correlation energies of its ionic fragments derived from the ionic partitioning scheme rather than from the diradical partitioning scheme. Of the three estimated results, the absolute deviations are less than Ϯ0.29 kcal/mol, however, using this simple scaling approach, at least 90% of computational work can be saved. At the present condition with the computational demand for calculating the electron correlation energies of large covalent molecules, it is hopeful that this simple scaling approach could be useful to estimate the correlation energies of large CH-containing alkaline compounds.

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