Linear geometry INDEX

The work functions for low-index surfaces of the 4d transition metals have been calculated by a full-potential linear-muffin-tin-orbital method using a slab geometry (a periodic arrangement of 7-layer metal slabs and 10-layer vacuum slabs) (29), and the results (Fig. 8) agree well with experimental results. This is a considerable improvement with respect to extended Hiickel calculations for slab [30 (see footnote 21) ] or cluster [i0 (see Chapter 3)] geometries, which usually yield values closer to the atomic ionization energies. However, the shape of the DOS curves and the relative position of the Fermi level as found by the extended Hiickel calculations are reasonably similar to those obtained by the more sophisticated methods. Therefore, it seems that the major error is in the determination of the dipole layer potential. (Further analysis of this topic would lead us beyond the scope of this chapter.)... 

Geometry optimizations were carried out by using the PM3 or AM 1 approaches. Satisfactory linear correlations with normal boiling points for 53 alkenes were obtained (r = 0.984, s = 5.6 °C) with the Q( ) and D/ q) indices [in the last case, 8 q) values are replaced by values], as well as with the Kier-Hall 2D-index x abetter... 

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