Used in the following paper:

Low frequency vibrational spectrum of Green Fluorescent Protein's
mutant: a Raman SERS and Density Functional Theory study,
V. Tozzini, A. R. Bizzarri, V. Pellegrini, R. Nifosi', P. Giannozzi,
A. Iuliano, S. Cannistraro, F. Beltram, Chem. Phys. 287/1-2,
33 (2003).