  We introduce an approximation to the short-range correlation energy
functional with multide-terminantal reference involved in a variant of
range-separated density-functional theory. This approximation is a local
functional of the density, the density gradient, and the on-top pair density,
which locally interpolates between the standard Perdew-Burke-Ernzerhof
correlation functional at vanishing range-separation parameter and the known
exact asymptotic expansion at large range-separation parameter. When combined
with (selected) configuration-interaction calculations for the long-range wave
function, this approximation gives accurate dissociation energy curves of the
H2, Li2, and Be2 molecules, and thus appears as a promising way to accurately
account for static correlation in range-separated density-functional theory.
