Time Evolution
Description: ALGO= timeev calculates the frequency dependent dielectric matrix after the electronic ground state has been determined using the time evolution algorithm (only available in vasp.6)
The timepropagation algorithm applies an short electric field puls in time, and then follows the evolution of the dipole moments. The Green-Kubo relation then allows to calculate the frequency dependent dielectric response function from the time evolution of the dipole moments [1]. Details of the implementation are explained in [2]
VASP posses multiple other routines to calculate the frequency dependent dielectric function.
The simplest approach uses the independent particle approximation (LOPTICS=.TRUE.
Furthermore, one can use ALGO = TDHF (BSE calculations equivalent to solving the Casida equation), ALGO = GW (GW calculations).
For standard DFT, the timeevolution algorithm is
usually fastest, whereas for hybrid functionals ALGO = TDHF is
usually faster.
Related Tags and Sections
CSHIFT, LADDER, LHARTREE, NBANDSV, NBANDSO
References
- ↑ [http://journals.jps.jp/doi/10.1143/JPSJ.12.570 Ryogo Kubo, Statistical-Mechanical Theory of Irreversible Processes. I. General Theory and Simple Applications to Magnetic and Conduction Problems. In: Journal of the Physical Society of Japan. Band 12, Nr.6, 15. Juni 1957, S.570–586, doi:10.1143/JPSJ.12.57].
- ↑ [https://journals.aps.org/prb/abstract/10.1103/PhysRevB.92.045209 T. Sander, E. Maggio, and G. Kresse, Beyond the Tamm-Dancoff approximation for extended systems using exact diagonalization. Physical Review B, 92, 045209 (2015).]