Best methods for calculating interaction energies in 2-butene and butane systems

Publication date: 1 October 2017 Source:Computational and Theoretical Chemistry, Volume 1117 Author(s): Milana M. Zarić, Branko Bugarski, Mirjana Lj. Kijevčanin Benchmarking study on eighteen methods, including MP2, B2PLYP-D3, B2PLYP-D3BJ, ωB97xD, M05-D3, M06-D3, M052X-D3, M06HF-D3, PBE0-D3, PBE0-D3BJ, B3LYP-D3, B3LYP-D3DJ, TPSS-D3, TPSS-D3BJ, BP86-D3, BP86-D3BJ, BLYP-D3, BLYP-D3BJ and ten basis sets: cc-pVDZ, cc-pVTZ, aug-cc-pVDZ, cc-pVQZ, def2-SVP, def2-TZVP, def2-TZVPP, def2-QZVP, 6-311++G∗∗ and 6-31G∗∗, for each method, have been performed, calculating interaction energies in (1) unsaturated/unsaturated systems (2-butene dimers), (2) unsaturated/saturated system (between butane and 2-butene) and (3) saturated/saturated (butane dimers). The calculated interaction energies are compared with accurate CCSD(T)/CBS energies. The data show that most levels of theory have the highest errors for systems with butane dimers, and calculated interaction energies in these systems are overestimated. The best levels, overall for all systems, are BLYP-D3BJ/def2-QZVP and BLYP-D3BJ/cc-pVQZ with similar root mean square deviation (RMSD) values of 0.056kcalmol−1 and 0.060kcalmol−1 compared to CCSD(T) values. The best level for (1) 2-butene dimers is B3LYP-D3BJ/aug-cc-pVDZ; for (2) interactions between 2-butene and butane is BLYP-D3BJ/def2-SVP; while for (3) butane dimers is BLYP-D3BJ/def2-QZVP. The differences in calculated energies among several methods are not high, howe...

Source: Computational and Theoretical Chemistry - August 20, 2017 Category: Chemistry Source Type: research