On Thursday 25 May 2006 20:59, Jess Kondor wrote: > I found, that properties of my test system [rhombohedral unit cell] > (total energy, lattice constant, angle between cell vectors, unit-cell > volume) are almost identical to one obtained by using ecutrho=160 Ry. > [...] I am a little bit confused, because in ultrasoft case ecutrho should > be > 4*ecutwfc .
it may be, but not necessarily so. If it isn't, good for you. Consider that 40 Ry is a relatively high cutoff for Ultrasoft PP's. One tries to perform calculations with ecutwfc = 25 Ry or so. > My system contains 3 atomic species, one of them is iron. I > use Fe.pz-sp-van_ak.UPF pseudopotential. I read the info about > these pseudopotentials (unfortunately, for GGA only). I saw that > recommended value of ecutho should be around 10-12*ecutwfc. GGA PP's are typically nastier than LDA ones. Paolo -- Paolo Giannozzi e-mail: giannozz at nest.sns.it Scuola Normale Superiore Phone: +39/050-509876, Fax:-563513 Piazza dei Cavalieri 7 I-56126 Pisa, Italy
