In the recent research, we found that whereas conventional DFT functionals have given poor calculations on alkane isodesmic reaction energy and isomerization reaction energy of organic molecules including C, N, and O atoms,1,2 our developed LC- and LCgau-DFT+LRD3 functionals which can calculate well inter- and intra-molecular weak interactions successfully can give accurate isomerization energies on these reactions.
In this presentation, we show that B3LYP-D3 and wB97XD known for well describing weak interaction calculations failed in reproducing the isomerization reaction energies of the molecules with S atom, such as methylthiourea, iso-propylthiourea,. dimethylthiourea, but LCgau-BOP+LRD can successfully reproduce the isomerization reaction energies close to high accuracy wave function method, CCSD(T). Consequently, LCgau-BOP+LRD method is considered to be useful for large molecular system computations where inter- and intra-molecular weak interaction is important.
1) J.-W. Song, T. Tsuneda, T. Sato, and K. Hirao, Org. Lett. 12, 1440 (2010).
2) J.-W. Song, T. Tsuneda, T. Sato, and K. Hirao, Theor. Chem. Acc. 130, 851 (2011).
3) R. Kar, J.-W. Song, T. Sato, and K. Hirao, J. Comput. Chem. 34, 2353 (2013).