Time-dependent local-density approximation in real time

We study the dipole response of atomic clusters by solving the equations of the time-dependent local-density approximation in real time. The method appears to be more efficient than matrix or Green close-quote s function methods for large clusters modeled with realistic ionic pseudopotentials. As applications of the method, we exhibit results for sodium and lithium clusters and for C60 molecules. The calculated Mie resonance in Na147 is practically identical to that obtained in the jellium approximation, leaving the origin of the redshift unresolved. The pseudopotential effects are strong in lithium and act to broaden the Mie resonance and give it a substantial redshift, confirming earlier studies. There is also a large broadening due to Landau damping in the calculated C60 response, again confirming earlier studies. copyright 1996 The American Physical Society