TY - JOUR
T1 - Canonical and DLPNO-based G4(MP2)XK-inspired composite wavefunction methods parametrized against large and chemically diverse training sets
T2 - Are they more accurate and/or robust than double hybrid DFT?
AU - Semidalas, Emmanouil
AU - Martin, Jan M. L.
N1 - Research was supported by the Israel Science Foundation (grant 1358/15) and by the YedaSela-SABRA program (Weizmann Institute of Science).The work of ES on this scientific paper was supported by the Onassis Foundation - Scholarship ID: F ZP 052-1/2019-2020. JMLM would like to acknowledge Dr. Mark Vilensky (scientific computing manager of ChemFarm) for software development, and Mr. Jacov Wallerstein (CEO and CTO of Access Technologies) for hardware development, of the bscratch shared high-bandwidth scratch storage server, without which some of the largest conventional calculations would have been impossible. Peer reviewers are thanked for helpful suggestions. We would also like to thank Mr. Golokesh Santra and Dr. Mark A. Iron for helpful discussions. Author Contributions : The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript.
PY - 2020/7/14
Y1 - 2020/7/14
N2 - The large and chemically diverse GMTKN55 benchmark was used as a training set for parametrizing composite wavefunction thermochemistry protocols akin to G4(MP2)XK theory [B. Chan, A. Karton, K. Raghavachari, J. Chem. Theory Comput. 2019, 15, 4478–4484]. On account of their availability for elements H through Rn, Karlsruhe def2 basis sets were employed. Even after reparametrization, the GMTKN55 WTMAD2 (weighted mean absolute deviation, type 2) for G4(MP2)-XK is actually inferior to that of the best rung-4 DFT functional, ωB97M-V. By increasing the basis set for the MP2 part to def2-QZVPPD, we were able to substantially improve performance at modest cost (if an RI-MP2 approximation is made), with WTMAD2 for this G4(MP2)-XK-D method now comparable to the better rung-5 functionals (albeit at greater cost). A 3-tier approach with a scaled MP3/def2-TZVPP intermediate step, however, leads to a G4(MP3)-D method that is markedly superior to even the best double hybrids ωB97M(2) and revDSD-PBEP86-D4. Evaluating the CCSD(T) step with a triple zeta, rather than split-valence, basis set yields only a modest further improvement that is incommensurate with the drastic increase in computational cost. G4(MP3)-D and G4(MP2)-XK-D have about 40% better WTMAD2, at similar or lower computational cost, than their counterparts G4 and G4(MP2), respectively: detailed comparison reveals the difference lies in larger molecules due to basis set incompleteness error. An E2/{T,Q} extrapolation and a CCSD(T)/def2-TZVP step provided the G4-T method of high accuracy and 3 fitted parameters. Using KS orbitals in MP2 leads to the G4(MP3|KS)-D method, which entirely eliminates the CCSD(T) step and has no steps costlier than scaled MP3; this shows a path forward to further improvements in double-hybrid density functional methods. None of our final selections require an empirical HLC correction; this cuts the number of empirical parameters in half and avoids discontinuities on potential energy surfaces. G4-T-DLPNO, a variant in which post-MP2 corrections are evaluated at the DLPNO-CCSD(T) level, achieves nearly the accuracy of G4-T but is applicable to much larger systems.
AB - The large and chemically diverse GMTKN55 benchmark was used as a training set for parametrizing composite wavefunction thermochemistry protocols akin to G4(MP2)XK theory [B. Chan, A. Karton, K. Raghavachari, J. Chem. Theory Comput. 2019, 15, 4478–4484]. On account of their availability for elements H through Rn, Karlsruhe def2 basis sets were employed. Even after reparametrization, the GMTKN55 WTMAD2 (weighted mean absolute deviation, type 2) for G4(MP2)-XK is actually inferior to that of the best rung-4 DFT functional, ωB97M-V. By increasing the basis set for the MP2 part to def2-QZVPPD, we were able to substantially improve performance at modest cost (if an RI-MP2 approximation is made), with WTMAD2 for this G4(MP2)-XK-D method now comparable to the better rung-5 functionals (albeit at greater cost). A 3-tier approach with a scaled MP3/def2-TZVPP intermediate step, however, leads to a G4(MP3)-D method that is markedly superior to even the best double hybrids ωB97M(2) and revDSD-PBEP86-D4. Evaluating the CCSD(T) step with a triple zeta, rather than split-valence, basis set yields only a modest further improvement that is incommensurate with the drastic increase in computational cost. G4(MP3)-D and G4(MP2)-XK-D have about 40% better WTMAD2, at similar or lower computational cost, than their counterparts G4 and G4(MP2), respectively: detailed comparison reveals the difference lies in larger molecules due to basis set incompleteness error. An E2/{T,Q} extrapolation and a CCSD(T)/def2-TZVP step provided the G4-T method of high accuracy and 3 fitted parameters. Using KS orbitals in MP2 leads to the G4(MP3|KS)-D method, which entirely eliminates the CCSD(T) step and has no steps costlier than scaled MP3; this shows a path forward to further improvements in double-hybrid density functional methods. None of our final selections require an empirical HLC correction; this cuts the number of empirical parameters in half and avoids discontinuities on potential energy surfaces. G4-T-DLPNO, a variant in which post-MP2 corrections are evaluated at the DLPNO-CCSD(T) level, achieves nearly the accuracy of G4-T but is applicable to much larger systems.
U2 - https://doi.org/10.1021/acs.jctc.0c00189
DO - https://doi.org/10.1021/acs.jctc.0c00189
M3 - مقالة
C2 - 32456427
SN - 1549-9618
VL - 16
SP - 4238
EP - 4255
JO - Journal of Chemical Theory and Computation
JF - Journal of Chemical Theory and Computation
IS - 7
ER -