In data 26 ottobre 2009 alle ore 18:03:00, Bertrand SITAMTZE <siyouber at yahoo.fr> ha scritto: > What is the size of the system in QE calculations (1 unit cell, 2, 3, > ....)?
Dear Betrand, most of Quantum-ESPRESSO programs and utilities use a plane-wave basis set and periodically boundary conditions: the size of the system is always formally infinite. The ions are repeats infinite times whatever you put in the unit cell. The periodicity of electronic wavefunctions is a slightly different story which depends on the number and positions of the k-points. It is a bit long to explain. I can go in details, if necessary (although not tonight for lack of time), but it would be better for you to study it off some solid-state book first and ask for the necessary clarifications. 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/
