Locally Range-Separated Hybrids as Linear Combinations of Range-Separated Local Hybrids

Range-separated hybrid density functionals, which incorporate different fractions of exact exchange at different interelectronic separations, offer substantial advantages over conventional global hybrid functionals. However, they generally use a fixed, system-independent range-separation parameter, which numerical experience and formal arguments both show to be a limiting approximation. Locally range-separated hybrids, which instead use a position-dependent range-separation function, should overcome this limitation, but their implementation is nontrivial. Here, we present a method which in practice converts a locally range-separated hybrid into a linear combination of range-separated local hybrids. Thus, unlike our previous implementation of this locally range-separated hybrid idea, we do not need to approximate the exchange hole, and we can take advantage of existing self-consistent local hybrid implementations to carry out self-consistent calculations using locally range-separated hybrid functionals. © 2009 Wiley Periodicals, Inc. Int J Quantum Chem 109: 2023–2032, 2009