In data 23 giugno 2009 alle ore 11:29:28, Vladan Stevanovic <vladan.stevanovic at epfl.ch> ha scritto: > I am using QE for simulations of transition metal clusters. My question > is where the code places the vacuum level in such calculations > (nonperiodic systems in a big cell) ?
Dear Vladan, a non-periodic system in a big periodic cell is still a periodic system! Hence, the integral of the potential over any possible choice of primitive cell has to be zero. This is a sufficient condition to find the zero. > To formulate differently, is it > possible to compare directly KS eigenvalues from different calculations ? In general it is NOT possible to directly compare eigenvalues of different calculations, nevertheless they can be compared taking the Fermi energy as reference. best regards -- Lorenzo Paulatto SISSA & DEMOCRITOS (Trieste) phone: +39 040 3787 511 skype: paulatz www: http://people.sissa.it/~paulatto/ *** save italian brains *** http://saveitalianbrains.wordpress.com/
