Hi all, I am interested in anharmonic properties of crystals and I would like to calculate the third order derivatives of energy with respect to changes in lattice position. PWscf does a great job of calculating the interatomic force constants. I was wondering if it is possible to calculate the 3rd order terms for arbitrary q,q', and q''. I have looked at the d3.x code, but I believe this program only calculates terms of the form (0,q,-q). I would be interested in any suggestions people have on calculating these terms. Is this feature in the works for PWscf? Also, can d3.x now handle ultrasoft pseudopotentials?
Thanks in advance for your help! Best regards, Derek ################################ Derek Stewart, Ph. D. Scientific Computation Associate 250 Duffield Hall Cornell Nanoscale Facility (CNF) Ithaca, NY 14853 stewart (at) cnf.cornell.edu (607) 255-2856
