Dear QE experts, I am trying to refine computation of 3-NT adsorption on metal doped graphene using QE. This is according to our previous work http://dx.doi.org/10.1016/j.commatsci.2011.07.045
With the help of Dr. Guido Fratesi, I am exploring molecularpdos.x to find the change of HOMO and LUMO of the nitrated tyrosine molecule on adsorption to metal-doped graphene. There are my questions and answers, your comments are welcome. Q1) Spin polarization. The full system contains a metal doped graphene with single metallic atom of Au and Ni at the center and a 3-NT molecule adsorbed onto the graphene sheet, so I included nspin=2 for the full system. But the adsorbate (3-NT) molecule is likely to be nonmagnetic, so I did nspin=1 for its gas phase. Can molecularpdos.x cope with different nspin for the full system and adsorbate? A1) Yes, since nspin=2 can handle a nonmagnetic case R1) So, I am adding nspin=2 to the 3-NT molecules Q2) K-points. I used smearing for the full system since it is semi-metallic. Should I use smearing for the molecule in gas phase? I believe this is not a good idea but can molecularpdos.x works with k-point and non k-point? A2) Smearing: no problem, K-points: should be the same R2) So, I am using the same K-points for both full system and single molecule. Q3) I would like to evaluate the change of the HOMO-LUMO gap of the adsorbate (3-NT) on adsorption to the metal-doped graphene. Can molecularpdos.x do that? A3) Dr. Fratesi and his team used that code also to study molecules/graphene... http://dx.doi.org/10.1038/srep24603 R3) Very useful and thank you! Q4) I would like to determine if physisorption or chemisorption occurs as with DMol3, can molecularpdos.x do the same job? For the physisorption vs. chemisorption, the adsorption energy may be a good indicator. However, I believe the electronic structure of the bond may also indicate which type of adsorption it suppose to be? With regards, Rolly -- PhD. Research Fellow, Dept. of Physics & Materials Science, City University of Hong Kong Tel: +852 3442 4000 Fax: +852 3442 0538 _______________________________________________ Pw_forum mailing list Pw_forum@pwscf.org http://pwscf.org/mailman/listinfo/pw_forum