General Performance Overview of DFT

105 molecules having high overlap with test set C, see Hoe, Cohen, and Handy (2001). 

Hybrid and meta-GGA DFT functionals usually offer some improvement over corresponding pure DFT functionals. 

Increasing basis-set size does not always improve the accuracy of the DFT models, although it must, of course, ultimately lead to a converged prediction. 

While fewer data are available, the utility of DFT in computing the bond strengths between transition metals and hydrides, methyl groups, and methylene groups has also been demonstrated (Table 8.2). Because of the non-dynamical correlation problem associated with the partially filled metal d orbitals, such binding energies are usually very poorly predicted by MO theory methods, until quite high levels are used to account for electron correlation. 

In the area of reaction energetics. Baker, Muir, and Andzehn have compared six levels of theory for the enthalpies of forward activation and reaction for 12 organic reactions the unimolecular rearrangements vinyl alcohol - acetaldehyde, cyclobutene - s-trans butadiene, s-cis butadiene s-trans butadiene, and cyclopropyl radical allyl radical the unimolecular decompositions tetrazine - 2HCN -F N2 and trifluoromethanol - carbonyl difluoride -F HF the bimolecular condensation reactions butadiene -F ethylene - cyclohexene (the Diels-Alder reaction), methyl radical -F ethylene - propyl radical, and methyl radical -F formaldehyde - ethoxyl radical and the bimolecular exchange reactions FO -F H2 FOH -F H, HO -F H2 H2O -F H, and H -F acetylene H2 -F HC2. Their results are summarized in Table 8.3 (Reaction Set 1). One feature noted by these authors is 

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Abstract A review is provided on the contribution of modern surface-science studies to the understanding of the kinetics of DeNOx catalytic processes. A brief overview of the knowledge available on the adsorption of the nitrogen oxide reactants, with specific emphasis on NO, is provided first. A presentation of the measurements of NO, reduction kinetics carried out on well-characterized model system and on their implications on practical catalytic processes follows. Focus is placed on isothermal measurements using either molecular beams or atmospheric pressure environments. That discussion is then complemented with a review of the published research on the identification of the key reaction intermediates and on the determination of the nature of the active sites under realistic conditions. The link between surface-science studies and molecular computational modeling such as DFT calculations, and, more generally, the relevance of the studies performed under ultra-high vacuum to more realistic conditions, is also discussed. 

We are aware of only two reviews (book chapters) devoted solely to the theoretical smdy of oligothiophenes and polythiophenes [2, 3]. Since these were published in 1998 [2] and 1999 [3], the present chapter covers mostly research published after 1998. Due to the significant number of pubiications over the last 10 years that include theoretical studies on thiophene-containing compounds, we have not attempted to write a comprehensive review and to cover all available publications. Rather, our aim is to provide an overview of the field. We decided to concentrate on representative case studies of thiophene-containing compounds and not necessarily on the deepest or most comprehensive studies hence some other important studies are not covered in this review. Most theoretical studies were performed on oligomers however, where polymer calculations are available, they are also included in this review. We note that, since around 1996-99, density functional theory (DFT) has become the most popular computational tool in chemistry in general and in material chemistry in particular. Earlier reviews, published before 2000, concentrated... 

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