  We present an approach for generating local numerical basis sets of improving
accuracy for first-principles nanoplasmonics simulations within time-dependent
density functional theory. The method is demonstrated for copper, silver, and
gold nanoparticles that are of experimental interest but computationally
demanding due to the semi-core d-electrons that affect their plasmonic
response. The basis sets are constructed by augmenting numerical atomic orbital
basis sets by truncated Gaussian-type orbitals generated by the
completeness-optimization scheme, which is applied to the photoabsorption
spectra of homoatomic metal atom dimers. We obtain basis sets of improving
accuracy up to the complete basis set limit and demonstrate that the
performance of the basis sets transfers to simulations of larger nanoparticles
and nanoalloys as well as to calculations with various exchange-correlation
functionals. This work promotes the use of the local basis set approach of
controllable accuracy in first-principles nanoplasmonics simulations and
beyond.
