On Dec 16, 2011, at 17:50 , Hua Bao wrote: > The electron-phonon matrix element is written in terms of ibnd, > jbnd, ik, ipert+imode0. (in elphon file) [...] However, I am still > having difficulty to project nirr/npert to a specific \nu.
you shouldn't need to project anything. Electron-phonon matrix elements have to be symmetrized. The irrep basis is used for symmetrization. After symmetrization, the electron-phonon matrix elements are expressed in the basis of atomic displacements. Phonons are available in the basis of displacements as well. So you can forget about irreps. Or at least, this is what I remember, in at least one of the many possible ways to calculate electron-phonon coefficients. In the current development version, there are three, plus one with an external code P. --- Paolo Giannozzi, Dept of Chemistry&Physics&Environment, Univ. Udine, via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
