DP code
DP is a free software package for physicists implementing ab initio linear-response TDDFT in frequency-reciprocal space and on a plane wave basis set.
It allows to calculate both dielectric spectra, such as EELS, IXSS and CIXS, and also optical spectra, e.g. optical absorption, reflectivity, refraction index.
The systems range from periodic/crystalline solids, to surfaces, clusters, molecules and atoms made of insulators, semiconductors and metal elements. It implements the RPA, the TDLDA or ALDA plus other non-local approximations, including or neglecting local-field effects. It is distributed under the scientific software open-source academic for free license.