The Berkeley XAS tool is suitable for the calculation of K-edge spectra of molecular systems.
Tool overview available at https://docs.google.com/present/edit?id=0AWZVKNsRXgTbZGdwMzZreGZfMTRjZDdqMzgyZw (outdated)
Berkeley XAS currently has support for the following atomic species: H, C, N, O
Experimental data taken from the Hitchcock Group's Core Excitation Database: http://unicorn.mcmaster.ca/corex/cedb-title.html
Researchers should cite this work as follows: