23 research outputs found
Employing Range Separation on the meta-GGA Rung: New Functional Suitable for Both Covalent and Noncovalent Interactions
We devise a scheme for converting
an existing exchange functional
into its range-separated hybrid variant. The underlying exchange hole
of the Becke-Roussel type has the exact second-order expansion in
the interelectron distance. The short-range part of the resulting
range-separated exchange energy depends on the kinetic energy density
and the Laplacian even if the base functional lacks the dependence
on these variables. The most successful practical realization of the
scheme, named LC-PBETPSS, combines the range-separated Perdew–Burke–Ernzerhof
(PBE) exchange lifted to the hybrid meta-generalized gradient approximation
rung and the Tao–Perdew–Staroverov–Scuseria (TPSS)
correlation. The value of the range-separation parameter is estimated
theoretically and confirmed by empirical optimization. The D3 dispersion
correction is recommended for all energy computations employing the
presented functional. Numerical tests show remarkably robust performance
of the method for noncovalent interaction energies, barrier heights,
main-group thermochemistry, and excitation energies