On Aug 20, 2009, at 21:03 , Mikiyas Tsegaye wrote: > For examples, the acoustic modes don't go to zero at the gamma point
you need to enforce acoustic sum rule > and the acoustic and optical branches don't touch at the K-point they do. Some time ago I heard a similar claim. I verified that they touch at K. P. --- Paolo Giannozzi, Dept of Physics, University of Udine via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
