Does a Molecule-Specific Density Functional Give an Accurate Electron Density? The Challenging Case of the CuCl Electric Field Gradient.
In the framework of determining system-specific long-range corrected density functionals, the question is addressed whether such functionals, tuned to satisfy the condition -ε(HOMO) = IP or other energetic criteria, provide accurate electron densities. A nonempirical physically motivated two-dimensional tuning of range-separated hybrid functionals is proposed and applied to the particularly challenging case of a molecular property that depends directly on the ground-state density: the copper electric field gradient (EFG) in CuCl. From a continuous range of functional parametrizations that closely satisfy -ε(HOMO) = IP and the correct asymptotic behavior of the potential, the one that best fulfills the straight-line behavior of E(N), the energy as a function of a fractional electron number N, was found to provide the most accurate electron density as evidenced by calculated EFGs. The functional also performs well for related Cu systems.
†Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States.|‡Department of Theoretical Chemistry, Faculty of Chemistry, Jagiellonian University, 30-060 Krakow, Poland.
Monika
M
Srebro
†Department of Chemistry, University at Buffalo, State University of New York, Buffalo, New York 14260-3000, United States.
Jochen
J
Autschbach
copper chloride; density functional theory; electric field gradient; localized molecular orbitals; range-separated exchange; system-specific functionals