In data 28 luglio 2009 alle ore 11:54:14, Neel Singh <neelphysics at yahoo.in> ha scritto: > means band gap at gamma = 0.3058-(-8.9833)= 8.2891 > which is very large ??
Not necessarily, the offset of band in a periodic system is arbitrary. You need to know where you Fermi energy is, or which are the HOMO and LUMO of your system to find the gap. > 2) In the output of SCF and Bands , the output file has 4 warnings This a very frequently asked question, please see the corresponing entry in the manual: http://www.pwscf.org/guide/2.1.2/html-node/node56.html http://www.pwscf.org/guide/2.1.2/html-node/node57.html > for this I have already increase the following quantities in the > increments > kinetic-energy cutoff = 40.0000 Ry to 60 > charge density cutoff = 250.0000 Ry to 400 > But still the warnings are there. It is not a big increment of the cutoff that will solve this problem, but a small increment or nr1, nr2 nr3 cheers, and good work -- 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/
