Assessing the performance of popular QM methods for calculation of conformational energies of trialanine

Relationship between (a) the linear correlation coefficients (R2); (b) root-mean-square deviation (RMSD) and the computational cost (CPU time) at different QM levels (with the ADZ basis set) for 51 trialanine conformations with reference to the DF-LCCSD(T)/CBS results.87