All-electron fixed-node diffusion Monte Carlo provides benchmark spin gaps for four Fe(II) octahedral complexes. Standard quantum chemical methods (semilocal DFT and CCSD(T)) fail badly for the energy difference between their high- and low-spin states. Density-corrected DFT is both significantly more accurate and reliable and yields a consistent prediction for the Fe-Porphyrin complex.
Bibliographical noteFunding Information:
Work at Yonsei University (2016-22-0121) was supported by grants from the Korean Research Foundation (2017R1A2B2003552). K.B. acknowledges NSF grant CHE- 1464795. A.B. and O.H. were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, as part of the Computational Materials Sciences Program and Center for Predictive Simulation of Functional Materials. Diffusion Monte Carlo calculations were carried out through an award of computer time provided by the Innovative and Novel Computational Impact on Theory and Experiment (INCITE) program. This research has used resources of the Argonne Leadership Computing Facility, which is a DOE Office of Science User Facility supported under Contract DE-AC02-06CH11357. We thank Professors Frederick Manby and Filipp Furche for stimulating discussions and Dr. Jefferson E. Bates for providing the SCAN executable under the optimization phase.
All Science Journal Classification (ASJC) codes
- Computer Science Applications
- Physical and Theoretical Chemistry