Mimicking the Two-Dimensional Spectrochemical Series Using Density Functional Computations.

With tetragonal distortions of tetrahedral d² complexes as examples, nonadditive and additive ligand fields are compared computationally, using Kohn-Sham density functional theory (KS-DFT) and ligand-field theory to obtain 45 linear, parametrical equations. For each complex, a ‘data’ reduction from three nonadditive-field parameters to two parameters of the additive field occurs. The complexes VX4- and CrX4 (where X = F, Cl, Br, I) provide the two-dimensional spectrochemical series of the σ and π AOM parameters, which are known semiempirically for the halide ligands. The same parametrical results can be obtained from the Kohn-Sham orbital energies of the ‘average of configuration’ computation. [ABSTRACT FROM AUTHOR]