Study of weakly bound cluster anions using locally scaled and Perdew-Zunger self-interaction-correction methods.

Accurate description of weakly bound electrons is difficult for the semi-local density functional approximations. Here we study weakly bound electrons in molecules and clusters using self-interaction-corrected density functional methods. These are the recently proposed local scaled self-interaction-correction (LSIC) method[1] and the widely known Perdew-Zunger (PZ) self-interaction-correction (SIC) method. The SIC is determined using the Fermi-Löwdin localized orbitals in both methods. Our results from the density plot difference show that these clusters bind the extra electron in dipole bound states. We also estimate vertical detachment energies from the absolute of the highest occupied eigenvalues. Our results show that LSIC provides better agreement with reference CCSD(T) values than PZSIC and MP2.
[1]. Zope et al. J. Chem. Phys., 151, 214108, (2019).