On Jan 31, 2007, at 3:50 PM, Alexander Shaposhnikov wrote: > > I have tried several slab models and the first conduction band > is still meaningless, i.e. much higher than it should be in real > crystall.
the absolute value of the energy levels are of course as meaningless as they are for a bulk calculation, and for the same reason: the average electrostatic potential of an infinite solid is ill defined (periodically repeated slabs do constitute an infinite, periodic, system). What you ought to look after is the position of individual energy levels *with respect to the value of the potential in the vacuum region*. > I have not tried to optimize the structures though. > > I guess, i have to > 1. Optimize the structure. fine > 2. Remove some electrons from the system, hoping to create surface > charge. I think that the value of the lumo energy with respect to the vacuum potential should be a fair estimate of the electron affinity you are looking for. S. --- Stefano Baroni - SISSA & DEMOCRITOS National Simulation Center - Trieste [+39] 040 3787 406 (tel) -528 (fax) / stefanobaroni (skype) Please, if possible, don't send me MS Word or PowerPoint attachments Why? See: http://www.gnu.org/philosophy/no-word-attachments.html -------------- next part -------------- An HTML attachment was scrubbed... URL: /pipermail/attachments/20070131/898aba84/attachment.htm
