Orbital composition

S = si> an(i since the orbital composition of the excited states, , differs from that i... 

In contrast, the NBO and NRT methods make no use of molecular geometry information (experimental or theoretical), but instead provide optimal descriptions of orbital composition or electron-density distributions based directly on the first-order density operator. For this reason the NBO/NRT indices have predictive utility for a broad range of chemical phenomena, without bias toward geometry or other particular empirical properties. 

We now discuss systematic hyperconjugative effects on orbital composition and stabilization, torsion barriers, and spectroscopic properties, for the CH2=CHX species summarized in Table 3.22. 

The redox ability of a metal complex will be considered in the context of its molecular orbital composition and spin state. In this regard, Figure 1 shows the molecular orbital diagrams for the most common geometries encountered in transition metal complexes. 

Table I shows the atomic orbital composition and energies of the ground-state molecular orbitals of the nitrosyl ferric heme complex at three Fe-NO distances of 1.743 (bonding), 1.943, and 2.143 A.

From the experimental viewpoint 1. the analysis of the variation of photoionization cross sections (affecting the intensities of photoelectron spectroscopy), gives an insight into the orbital composition of the bands of the solid 2. the combination of direct and inverse photoemission provides a powerful tool to assess the structure of occupied and of empty states, and, in the case of localized 5 f states, permits the determination of a fundamental quantity, the Coulomb correlation energy, governing the physical properties of narrow bands. 

The orbital composition data summarized in table 11.2 indicate the extent of... 

Fig. 16. Atomic orbital composition sketches of some molecular orbitals of closo-1,2,3-SnC2B4H6. [Reprinted with permission from J. A. Maguire etal. (43), Inorg. Chem. 27, 3354 (1988). Copyright 1988 by the American Chemical Society.]...

Extended Hiickel calculations have been used to probe the nature of the HOMO and LUMO wave functions for Pt(diimine)(dithiolene) complexes (252). These calculations reveal a HOMO orbital composition for Pt(bpy)(mnt), which is 27% Pt, and 72% dithiolene. The LUMO for this complex contains dominant contributions from the bpy ligand with 2% Pt and 98% bpy character. The appreciable degree to which Pt orbitals contribute to the HOMO is the origin of the MMLL CT description for these complexes. These results compare... 

The orbital composition of each configuration of each state was identified with a serial number. The configurations which have the largest weight in the resulting wave functions are listed below according to their serial numbers (here all the a orbitals are listed first, followed by the n orbitals they are not... 

Molecular orbital Calculated atomic-orbital composition" Intensities ... 

Table 4.20. Molecular-orbital compositions in three MnO clusters for crystal-field-type and bonding orbitals shown in terms of percentage Mn, percentage O, and percentage intersphere contributions...

Table 5.11. Electronic structure of the COj cluster molecular-orbital compositions in terms of atomic-orbital components based on ab initio Hartree-Fock-Roothaan SCF calculations"...

An extensive study has recently been made of [WgXgXg]2- clusters, comparing DF theory, Huckel MO results, an experimental luminescence and absorption bands [101]. Here we focus mainly on the NR vs R consequences. The Mulliken populations and net atomic charges of the [WgXgX ]2 clusters obtained from NR and R DV calculations are presented in Table VI. The symmetry type of the frontier orbitals and the gap between the HOMO and LUMO are summarized in Table VII experimental absorption edge and emission maxima are also included. The atomic orbital compositions of the HOMO and LUMO from the two calculations differ primarily in their W 5d content, in the order NR> R as expected. 

Table I. Bond orders and orbital compositions for MCp2 and MBz2 systems...

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