GVB-CISD

However, there is recent work indicating that some or all of these shortcomings will be overcome in the near future. For example, Konkoli, Kraka, and Cremer have improved the RPH approach so that it can readily be applied to reaction systems with six and more heavy atoms as their investigation of the Diels-Alder reaction between ethene and butadiene shows. There are some applications that use modem correlation corrected methods such as MP2, QCISD, or GVB-CISD (Table 3). Particularly promising seems to be the use of DFT although further improvements of DFT are needed to describe loosely bound TSs and the reaction complex in the van der Waals region of the RP. DFT is attractive because of its relatively low computational cost and the fact that a considerable part of correlation corrections is covered, which gives DFT results of MP2 or even better accuracy. 

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