Exact exchange-correlation kernels for optical spectra of model systems

TY - JOUR

T1 - Exact exchange-correlation kernels for optical spectra of model systems

AU - Entwistle, M. T.

AU - Godby, R. W.

N1 - Rapid Communications

PY - 2019/4/3

Y1 - 2019/4/3

N2 - For two prototype systems, we calculate the exact exchange-correlation kernels fxc(x,x′,ω) of time-dependent density functional theory. fxc, the key quantity for optical absorption spectra of electronic systems, is normally subject to uncontrolled approximation. We find that, up to the first excitation energy, the exact fxc has weak frequency dependence and a simple, though nonlocal, spatial form. For higher excitations, the spatial behavior and frequency dependence become more complex. The accuracy of the underlying exchange-correlation potential is of crucial importance.

AB - For two prototype systems, we calculate the exact exchange-correlation kernels fxc(x,x′,ω) of time-dependent density functional theory. fxc, the key quantity for optical absorption spectra of electronic systems, is normally subject to uncontrolled approximation. We find that, up to the first excitation energy, the exact fxc has weak frequency dependence and a simple, though nonlocal, spatial form. For higher excitations, the spatial behavior and frequency dependence become more complex. The accuracy of the underlying exchange-correlation potential is of crucial importance.

UR - http://www.scopus.com/inward/record.url?scp=85064119210&partnerID=8YFLogxK

U2 - 10.1103/PhysRevB.99.161102

DO - 10.1103/PhysRevB.99.161102

M3 - Article

AN - SCOPUS:85064119210

VL - 99

JO - Physical Review B

JF - Physical Review B

SN - 2469-9950

IS - 16

M1 - 161102

ER -