On Sep 16, 2008, at 7:39 , Lawrence Lee wrote: > The meaning of "a" in the phonon calculation the same as in a scf calculation: a is the lattice parameter Paolo --- Paolo Giannozzi, Dept of Physics, University of Udine via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222