On Aug 1, 2009, at 5:59 , lidonglin556 wrote: > Did you calculate some larger system's frequence? [...] > I want to calculate a larger system of 100 atoms' frequence > and hope it quickly.
> you mean: vibrational frequences? you can't calculate vibrational frequencies for 100 atoms quickly. It takes 3*100 linear-response calculations per phonon wavevector, each one costing as much as, and usually more than, the corresponding self-consistent calculation. A 40-atom calculation for 11 wavevectors took 10 days on a fast PC, many hours on a parallel machine Paolo --- Paolo Giannozzi, Dept of Physics, University of Udine via delle Scienze 208, 33100 Udine, Italy Phone +39-0432-558216, fax +39-0432-558222
