rei4dan@gmail.com sci-chemistry@gentoo.org Gentoo Chemistry Project ERKALE is a quantum chemistry program used to solve the electronic structure of atoms, molecules and molecular clusters. It was developed at the University of Helsinki, and is currently developed at Aalto University. The main use of ERKALE is the computation of x-ray properties, such as ground-state electron momentum densities and Compton profiles, and core (x-ray absorption and x-ray Raman scattering) and valence electron excitation spectra of atoms and molecules.