Performance of Long-Range Corrected Functionals

Popular generalized gradient approximations (GGA) to the exchange-correlation functional are accurate and useful in many different physical systems. However they have several well-documented shortcomings, including the incorrect asymptotic behavior. One manifestation of this is that linear response time-dependent density functional calculations of vertical excitation energies with GGA functionals sharply underestimate charge-transfer excitations in large systems. Consequently, such functionals are not reliable for calculations in such situations, for example, biomolecules in solution. To circumvent this problem, a number of long-range-corrected functionals (based on GGAs) have recently been developed, which posses the correct asymptotic form by construction. We analyze the performance of some of these functionals through a battery of tests, and demostrate that there exists a functional form and parameter set that provide reasonable results for both ground-state properties and vertical excitation energies. We find these functionals suitable for general use in large condensed-phase systems.