Crystal orbital overlap population curves

Figure 20 Total density of states (left), and Pt-H (middle) and Pt-Pt (right) crystal orbital overlap population curves for the eclipsed PtH,2- stack.

Figure 29 Crystal orbital overlap population curves for the Mn-Mn bonds (solid line) and Mn-P bonds (dotted line) in the Mn2P22 single layer.

The "Crystal Orbital Overlap Population" (COOP) [20] shows (Fig. 4) that all levels arising below the Fermi level are a and Jt bonding and the highest energy levels are ct and n antibonding however the specific COOP curves for each Mo-0 distance (Fig. 5) show a... 

The orbital interaction which is responsible for the adsorption of molecular oxygen on the Ag(110) surface is mainly between silver dxz and 7t 0-0- The interaction between the silver surface and molecular oxygen leads to a donation of 1.55 electrons into the 7t o o from surface because the Fermi level of the surface is located higher in energy than n oo In Figure 1 is shown the contribution for the adsorbed molecular oxygen in 2 to the total density of states (DOS) and also the Ag-O and 0-0 crystal orbital overlap population (COOP) curves. 

Ultimately, the treatment of electronic structure in extended systems is no more complicated (nor is it less so) than in discrete molecules. The bridge to local chemical action advocated here is through decompositions of the DOS and the crystal orbital overlap population (COOP) curves. These deal with the fundamental questions Where are the electrons Where can I find the bonds ... 

A difficulty often associated with the use of overlap populations is that it is not sensible to compare values for different pairs of atoms. A useful tool derived within the DPT scheme is that of the crystal orbital Hamilton population (COHP) analysis [14]. In that case, what is partitioned in bonding, nonbonding, and antibonding contributions for a certain energy window is not the number of electrons (COOP) but the band energy (COH P). Except for the obvious fact that the two kinds of curves show opposite sign behavior, they usually lead to the same qualitative analysis. 

The overlap-population-weighted density of states. For a solid, COOP serves as the differential version of the bond order concept. The integral of the COOP curve up to the Fermi level is the total overlap population of the specified bond in a solid, whereas the value of COOP( )d represents the contribution to the total overlap population of those crystal orbitals whose energy levels lie in the range from to - - d . 

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