TY  - JOUR
A1  - Boese, Adrian Daniel
T1  - Assessment of coupled cluster theory and more approximate methods for hydrogen bonded systems
T2  - Journal of chemical theory and computation
N2  - To assess the accuracy of post-Hartree-Fock methods like CCSD(T), MP3, MP2.5, MP2, SCS-MP2, SOS-MP2, and DFT-SAPT, we evaluated several effects going beyond valence-correlated CCSD(T). For 16 small hydrogen bonded systems, CCSD(T) achieves an RMS error of 0.17 kJ/mol in the dissociation energy compared to our best estimate, which is a composite method akin to W4 theory. The error of CCSD(T) is thus much lower than for atomization energies. MP2 is surprisingly accurate for these systems with an RMS error of 1.3 kJ/mol. MP2.5 yields a clear improvement over MP2 (RMS of 0.5 kJ/mol) but still has an error about 3 times as large as CCSD(T) for the absolute RMS and almost 10 times as large for the relative RMS. error. Neither SCS-MP2, SOS-MP2, nor DFT-SAPT yield lower errors than MP2. With a Delta CCSD(T) correction to MP2, the basis set limit is readily achieved when employing diffuse functions-without these, the convergence is rather slow.
Y1  - 2013
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/34677
SN  - 1549-9618
SN  - 1549-9626
VL  - 9
IS  - 10
SP  - 4403
EP  - 4413
PB  - American Chemical Society
CY  - Washington
ER  -