Phonon Calculations and IBRION 8
Posted: Fri Jul 13, 2012 4:15 pm
In using IBRION=8 for phonon calculations, I am confused by the break conditions for the electronic sc loops. The initial sc loop always satisfies my convergence criteria specified by EDIFF; however, the following steps corresponding to each linear response degree of freedom typically do not meet the EDIFF criteria. Instead the values for dE and deps can be several orders of magnitude larger than EDIFF. The specified NEML has not been reached. Is there another parameter that needs to be set? How can I obtain reliable results?