Performance of dft sergio aragon san francisco state university caltech pasi january 4 16 2004
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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 aragon san francisco state university caltech pasi january 4 16 2004 l.jpg

Performance of DFT Sergio AragonSan Francisco State UniversityCalTech PASI January 4-16, 2004


H 2 dissociation curve l.jpg
H2 Dissociation Curve



Slide4 l.jpg

Bond lengths & Bond Angles

Koch &

Holthausen






Ionization energies l.jpg
Ionization Energies

HF under-estimates ionization energies: more correlation in the neutral than in the ion.


Electron affinities l.jpg
Electron Affinities

Affinities are very problematic for HF//anything methods. Extra electron adds correlation and is very diffuse.

DFT does reasonably well.


Excitation energies ethylene l.jpg
Excitation Energies: Ethylene

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.


Dipole moments l.jpg
Dipole Moments

HF predicts the wrong sign of the dipole moment for CO!

DFT performs very well.


Polarizabilities l.jpg
Polarizabilities

Polarizabilities are inversely proportional to orbital energy differences. DFT, with poor asymptotics, has high values of the HOMO energy and overestimates the polarizability.


Hydrogen bonding water dimer l.jpg
Hydrogen bonding: Water Dimer

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.


Further study l.jpg
Further Study

Koch, W. and Holthausen, M.C., “A Chemist’s Guide to Density Functional Theory”, Wiley-VCH: New York, 2000.

Further comparisons are available on:

IR intensities

NMR chemical shifts and spin-spin couplings

Hyperpolarizabilities

ESR tensors & Hyperfine couplings

Weakly bound systems & clusters.



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