Correlation functions for time-dependent calculation of linear-response functions

Abstract

We emphasize the importance of choosing an appropriate correlation function to reduce numerical errors in calculating the linear-response function as a Fourier transformation of a time-dependent correlation function. As an example we take dielectric functions of silicon crystal calculated with a time-dependent method proposed by Iitaka et al. [Phys. Rev. E 56, 1222 (1997)].