Performance of DFT Sergio Aragon San Francisco State University CalTech PASI January 4-16, 2004. H 2 Dissociation Curve. Performance: Ozone. Bond lengths & Bond Angles. Koch & Holthausen. Octahedral Cr Complex. Octahedral Metallic Carbonyls. Vibrational Frequencies. Thermochemistry.
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Performance of DFT Sergio AragonSan Francisco State UniversityCalTech PASI January 4-16, 2004
Bond lengths & Bond Angles
HF under-estimates ionization energies: more correlation in the neutral than in the ion.
Affinities are very problematic for HF//anything methods. Extra electron adds correlation and is very diffuse.
DFT does reasonably well.
Poor asymptotic behavior of ordinary functionals yields a deteriorating picture as the excitation energy increases.
Asymptotically corrected functionals such as PBE perform as well as the very expensive CAS methods.
HF predicts the wrong sign of the dipole moment for CO!
DFT performs very well.
Polarizabilities are inversely proportional to orbital energy differences. DFT, with poor asymptotics, has high values of the HOMO energy and overestimates the polarizability.
The fabulous numbers for the BLYP functional have been shown to be due to fortuitous error cancellation. Hybrid functionals do not overperform the HF//MP2 level.
Koch, W. and Holthausen, M.C., “A Chemist’s Guide to Density Functional Theory”, Wiley-VCH: New York, 2000.
Further comparisons are available on:
NMR chemical shifts and spin-spin couplings
ESR tensors & Hyperfine couplings
Weakly bound systems & clusters.