This work was performed under the auspices of the United States Department of Energy.
Physical Review A
Correlation (Statistics), Mathematical physics, Density functionals
A time-dependent direct correlation function (TDDCF) is defined and discussed. The definition (which differs from that proposed by Percus and Yevick) is motivated by linear response theory. The TDDCF consequently has a functional-derivative or stimulus-response interpretation closely analogous to that of the static direct correlation function. Mean-field considerations suggest that the TDDCF separates into a term which is simply related to the pair potential and a spatially shorter-ranged remainder. This behavior is confirmed in the Vlasov-Zwanzig approximation.
J.D. Ramshaw, "Time-dependent direct correlation function," Phys. Rev. A 24, 1567 (1981)