Assessment of CCSD(T), MP2, DFT-D, CBS-QB3, and G4(MP2) methods for conformational study of alanine and proline dipeptides

作者：Kang Young Kee^*; Park Hae Sook

来源：Chemical Physics Letters, 2014, 600: 112-117.

DOI：10.1016/j.cplett.2014.03.067

The CCSD(T), MP2, dispersion-corrected DFT, CBS-QB3, and G4(MP2) levels of theory with various basis sets are assessed for their ability to describe the conformational preferences of the Ala and Pro dipeptides. The omega B97X-D/6-311++G(d,p) level of theory provided the rotational constants of the most stable conformer of the Ala dipeptide consistent with the values from microwave experiments. The double-hybrid DSD-PBEP86-D3BJ DFT method provided the best performance for relative energies of both dipeptides consistent with CCSD(T)/CBS limit values. The DSD-PBEP86-D3BJ/cc-pVTZ//M06-2X/6-31+G(d), B2PLYPD-D3BJ/cc-pVTZ//M06-2X/6-31+G(d), and M06-2X/cc-pVTZ//M06-2X/6-31+G(d) levels of theory may be an alternative to the CCSD(T)/CBS limit//omega B97X-D/6-311++G(d,p) level of theory with marginal deviations for conformational study of peptides.

• 出版日期2014-4-29