Basis Sets STO

Table 1. shows the total energies obtained using the RHF method for 1. LCAO minimal basis set STO-IG for the sake of comparison with FSGO, 2. FSGO in its symmetric and broken symmetry solutions and, 3. LCAO minimal basis set STO-3G in order to allow a safer comparison with the quality of the subminimal basis used in the FSGO technique. The dissociation curves are given in Figure 1. 

As in the recent QCCD study by Head-Gordon et al. (28, 128), we tested the ECCSD, LECCSD, and QECCSD methods, based on eqs (52)-(59), using the minimum basis set STO-3G (145) model of N2. In all correlated calculations, the lowest two core orbitals were kept frozen. As in the earlier section, our discussion of the results focuses on the bond breaking region, where the standard CCSD approach displays, using a phrase borrowed from ref 128, a colossal failure (see Table II and Figure 2). 

Figure 7. Comparison between the absolute value of the electron correlation = Exact and the von Neumann entropy (S) as a function of the internuclear distance R for the H2 molecule using two Gaussian basis sets STO-3G and 3-21G.

Our focus is upon the fullerenes. In particular, the stability of C60 and C70 relative to the other fullerenes and to each other is of primary interest because these two species are the fullerenes produced in highest yield in carbon arcs and in combustion. Quite a few calculations mainly using various semi-empirical theories have been carried out to determine the stability of the fullerenes. Figure 2 shows the recent results of Scuseria s group (Strout et al. 1993), who carried out minimal basis set STO-3G SCF calculations on several fullerenes. The smooth curve fitted through... 

Between the wall of the cell and any ions (H+, H30+, H502+) forces of supermolecular hydrogen P-bonds and electrostatic y-bonds operate (see Fig. 2). Surfaces of intermolecular potential energy have been calculated by density functional method stated in our paper [6], Necessary data about spatial distributions of electron charge density inside framework of aqua multiparticle had been taken from calculations of aquatic ions and the ring of water (H20)n by using of standard molecular orbital method in the minimal basis set (STO-3G). Results of calculations are shown in Table 1. 

We will discuss Vs(r) and Is(r) calculated for (6,0) all-carbon and C/B/N model nanotubes. The computational level, Hartree-Fock (HF) STO-5G//STO-3G, was dictated by the large sizes of the systems. It has been confirmed, however, that minimum basis set STO-5G Hartree-Fock results for both v(r)64,65 and Is(r)65 are quite satisfactory on a relative basis, for seeing trends, which has been our objective. The validity of the HF/STO-3G geometry optimizations can be seen from the good agreement between our C-C and B-N bond lengths and relevant experimental data.28-31... 

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