The research described in this product was performed in part in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory. We present an implementation for considering finite lifetime of the electronic excited states into
linear-response theory within time-dependent density-functional theory. The lifetime of the excited
states is introduced by a common phenomenological damping factor. The real and imaginary
frequency-dependent polarizabilities can thus be calculated over a broad range of frequencies. This
allows for the study of linear-response properties both in the resonance and nonresonance cases. The
method is complementary to the standard approach of calculating the excitation energies from the
poles of the polarizability. The real and imaginary polarizabilities can then be calculated in any
specific energy range of interest, in contrast to the excitation energies which are usually solved only
for the lowest electronic states. We have verified the method by investigating the photoabsorption
properties of small alkali clusters. For these systems, we have calculated the real and imaginary
polarizabilities in the energy range of 1–4 eV and compared these with excitation energy
calculations. The results showed good agreement with both previous theoretical and experimental
results.
Revised: April 7, 2011 |
Published: June 16, 2005
Citation
Jensen L., J. Autschbach, and G.C. Schatz. 2005. "Finite Lifetime Effects on the Polarizability Within Time-dependent
Density-functional Theory." Journal of Chemical Physics 122. doi:10.1063/1.1929740