Local spin density method

We use an ab-initio local spin density method to investigate the aluminum/polyimide interface at low coverage. We found in agreement with XPS and EELS experiments, that the aluminum atom bonds to the carbonyl group. Our calculations suggest a formation of a linear C-O-AI complex. We calculated core levels chemical shifts and vibrational frequencies in the vicinity of the carbonyl group. 

Parts of the following overview of the local spin density method and the computational methods associated with it have been taken over from Ref. 22. 

A recent study by Andzelm and Salahub [78] is available using the Local Spin Density method, with qualitatively similar results. Post and Baerends [79] studied chemisorption of CO to Cu clusters using the HFS-X method. Of interest to our discussion are their results for the interaction of CO with Cu2. In their calculation, CO approaches Cu2 in a symmetrical way with its axis perpendicular to the Cu-Cu... 

Symp. 24, 29 (1990). Calculation of Equilibrium Geometries and Harmonic Frequencies by the LCGTO-MCP-Local Spin Density Method. See also R. J. Bartlett and J. F. Stanton, in Reviews in Computational Chemistry, Vol. 5, K. B. Lipkowire and D. B. Boyd, Eds., VCH Publishers, New York, 1994, pp. 65-169. Applications of Post-Hartree-Fock Methods A Tutorial. 

LORG (localized orbital-local origin) technique for removing dependence on the coordinate system when computing NMR chemical shifts LSDA (local spin-density approximation) approximation used in more approximate DFT methods for open-shell systems LSER (linear solvent energy relationships) method for computing solvation energy... 

We have used the multisublattice generalization of the coherent potential approximation (CPA) in conjunction with the Linear-MufRn-Tin-Orbital (LMTO) method in the atomic sphere approximation (ASA). The LMTO-ASA is based on the work of Andersen and co-workers and the combined technique allows us to treat all phases on equal footing. To treat itinerant magnetism we have employed for the local spin density approximation (LSDA) the Vosko-Wilk-Nusair parameterization". 

The muffin-tin potential around each atom in the unit cell has been calculated in the framework of the Local-Spin-Density-Approximation using the ASW method. The ASW method uses the atomic sphere approximation (ASA), i.e. for each atom a sphere radius is chosen such that the sum of the volumes of all the overlapping spheres equals the unit cell volume. The calculation yields the expected ferromagnetic coupling between Cr and Ni. From the self-consistent spin polarized DOS, partial and total magnetic moment per formula unit can be computed. The calculated total magnetic moment is 5.2 pg in agreement with the experimental value (5.3 0.1 e calculations presented here have been performed... 

Table4.4 Spectroscopic properties for Au2 q= -1,0, + 1) using ab-initio (Hartree Fock, HF, second-order Moller-Plesset, MP2, and coupled cluster, CCSD(T)) and DFT (local spin-density approximation, LSDA, Perdew-Wang CCA, PW91, and Becke three-parameter Lee-Yang-Parr functional, B3LYP) methods at the RPPA level of theory.

Table 9.1 presents excitation energies for a few atoms and ions. Calculations were performed with the generalized KLI approximation [69,74], For comparison, experimental data and the results obtained with the local-spin-density (LSD) exchange-correlation potential [75] are shown. The KLI method contains only the exchange. 

Table 8 summarizes the results of the calculations of the C2h symmetric chair and the C2v symmetric boat transition structures [83]. The local spin density approximation predicts a tight transition structure, comparable to the one obtained by the MP2(fc)/6-31G method, but fails to reproduce the experimental activation energies [84], The use of the gradient-corrected BLYP functional yields loose, aromatic-type transition structures and improved activation energies for the chair transition structures. The activation energy for the boat transition structure is, however, too low by 9-10 kcal/mol as compared to the experimental value of 44.7 kcal/mol [85]. The activation energies for the chair and the boat transition structures obtained by the Becke 3LYP method are in... 

Other workers135 have used a so-called local spin density (LSD) method, in which certain assumptions are made about how to calculate the exchange and correlation energies. They obtained results for both Mo2 and Cr2 that agree very well with the experimental data (both re and De values) for the ground states of these molecules. The success of this type of calculation in these two cases is impressive. Whether the method will be successful over a wide range of cases is still to be determined. 

This can be extended to the local spin density approximation (LSDA) for those cases where the a and p densities are not equal. Slater s X method is a scaled form of Eq. (1.52), and often the terms LSDA and Slater are used interchangeably. 

The cornerstone of the field (the "Hartree-Fock" of Density Functional Theory) is the Local Density Approximation (LDA) also called the Local (Spin) Density (LSD) method Here the basic information on electron correlation, how electrons avoid each other, is taken from the uniform density electron gas Essentially exact calculations exist for this system (the Quantum Monte Carlo work of Ceperley and Alder) and this information from the homogeneous model is folded into the inhomogeneous case through the energy integral ... 

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