Jan Jensen edited section_Introduction_Semiempirical_electronic_structure__.tex  over 8 years ago

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\section{Introduction}  Semiempirical electronic structure methods are increasingly parameterized and benchmarked against data obtained by DFT or wavefunction-based calculations using rather than experimental data (PM6, PM6-DH+, DFTB3, Von Lillienfeld). Using calculated data has the advantage that it represents the precise value (usually the electronic energy) that is being parameterized, with little random noise with good coverage of chemical space, including molecules that are difficult to synthesize or perform measurements on. Carefully curated benchmark sets, such as GMTKN30 \cite{Goerigk_2011}, are therefore an invaluable resource to the scientific community and heavily used. While In part because of these newer semiempirical methods such as PM6, OMD3 and DFTB3 are starting to rival the accuracy of standard DFT calculations for some properties, especially when combined with dispersion and hydrogen bond corrections. For example, Korth and Thiel have shown that ..   However,  there are comparatively few data sets on reactivity and most of these data sets are reactions that may not be relevant to enzymatic catalysis.  Accurate benchmarks great help in developing more accurate semi-empirical methods. Especially true for intermolecular interactions. There are fewer benchmark sets for barrier heights. Unlike intermolecular interaction benchmarks tend to be less representative of biologically relevant reactions. Here we xx