Converged approximate density functional calculations usually do not bind anions due to large self-interaction error. But Hartree-Fock (HF) calculations have no such problem, producing negative HOMO energies. Thus, electron affinities can be calculated from density functional total energy differences using approximations such as PBE and B3LYP, evaluated on HF densities (for both anion and neutral). This recently proposed scheme is shown to work very well for molecules, better than the common practice of restricting the basis set except for cases such as CN, where the HF density is too inaccurate due to spin contamination.
Bibliographical noteFunding Information:
We thank Professor Fillip Furche and Dr. Donghyung Lee for fruitful discussions. This work was supported by the global research network (Grant No. NRF-2010-220-C00017) and E.S. acknowledges the support under the national research foundation (Grant Nos. NRF-2010-0016487 and NRF-2010-0017172). K.B. acknowledges support under National Science Foundation (NSF) CHE-0809859 and M-C thanks the fellowship of the BK 21 program from MOEHRD.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry