Exchange-correlation asymptotics and high harmonic spectra

High harmonic spectra of N 2 are calculated using time-dependent density functional theory. The adiabatic local density approximation (A-LDA) and the adiabatic van Leeuwen–Baerends (A-LB94) approximations are used to study effects of differing spatial asymptotics. The LB94 potential corrects the LDA potential to the exact - 1 / r decay, but does not satisfy the zero-force condition. The A-LB94 makes a significant change in ionization probabilities but not in the relevant orbital contributions to ionization. This leads to qualitatively similar spectra, the exception being harmonic intensities. We also discuss why spurious dipoles induced by the A-LB94 do not affect significantly the structure of the N 2 harmonic spectrum.