CO LUMO-HOMO gap in GGA+U
Posted: Thu Sep 20, 2007 7:57 am
Dear All,
Prof. Kresse and Prof Hafner have resolved the CO/Pt, CO/Cu puzzle using GGA+U method (Phys. Rev. B 68,073401(2003),Surf. Sci. 590,117(2005)).
I'm also interested on the CO puzzle and want to reproduce their results using GGA+U method. But I encouter some problems when i calculate the CO LUMO-HOMO gap:
Based on Prof. Hafner's paper, the HOMO-LUMO gap will increase about 0.5 eV when U=0 increases to U=1.0 eV. But I just get a increase of 0.1261 eV, from 6.905 (-2.0564 - -8.9569) to 7.0311 eV (-1.9803 - -9.0114). I don't know what's wrong.
I choise LDAUTYPE = 2 and set p state U both on C and O atoms (J=0). I want to know wether these setting are right or not. And which atom should be set which state U?
Did there have someone who also ecountered similar problems or have reproduced this gap?Does the administrator know the U setting detail of these papers.
Thanks!
<span class='smallblacktext'>[ Edited ]</span>
Prof. Kresse and Prof Hafner have resolved the CO/Pt, CO/Cu puzzle using GGA+U method (Phys. Rev. B 68,073401(2003),Surf. Sci. 590,117(2005)).
I'm also interested on the CO puzzle and want to reproduce their results using GGA+U method. But I encouter some problems when i calculate the CO LUMO-HOMO gap:
Based on Prof. Hafner's paper, the HOMO-LUMO gap will increase about 0.5 eV when U=0 increases to U=1.0 eV. But I just get a increase of 0.1261 eV, from 6.905 (-2.0564 - -8.9569) to 7.0311 eV (-1.9803 - -9.0114). I don't know what's wrong.
I choise LDAUTYPE = 2 and set p state U both on C and O atoms (J=0). I want to know wether these setting are right or not. And which atom should be set which state U?
Did there have someone who also ecountered similar problems or have reproduced this gap?Does the administrator know the U setting detail of these papers.
Thanks!
<span class='smallblacktext'>[ Edited ]</span>