Zotero [zoh-TAIR-oh] is a free, easy-to-use Firefox extension to help you collect, manage, and cite your research sources. It lives right where you do your work—in the web browser itself.

SaX is an open-source package for the calculation of electronic and optical properties.

EXC[1] is a condensed matter physics many-body theory software package implementing the Bethe-Salpeter equation in frequency-reciprocal space and on a plane wave basis set. Its purpose is to calculate, ab initio, dielectric and optical properties, like absorption, reflectivity, refraction index, electron and X-ray energy loss, for a large variety of systems, ranging from bulk systems, surfaces, to clusters or atoms. It is distributed under the GNU/GPL license.

DP is a Linear Response TDDFT code, in Frequency-Reciprocal space, on a Plane Waves basis set.

YAMBO is a FORTRAN/C code for Many-Body calculations in solid state and molecular physics. YAMBO relies on the Kohn-Sham wavefunctions generated by two DFT public codes: abinit, and PWscf. The code has been originally developed in the Condensed Matter Theoretical Group of the Physics Department at the university of Rome by Andrea Marini.