Dear All,<br> I am now working on a project about carbon nanotube interacting with metal atoms. And I've got some problems:<br> 1. I forgot how I defined the celldm parameters.<br> Generally, I use a script for a (6,6) carbon nanotube like this:<br>
<br>&SYSTEM<br> ibrav = 6,celldm(1) = 21.764541128,celldm(3)=0.213765379<br> nat = 27,ntyp = 2,ecutwfc = 75 ,<br> occupations='smearing', smearing='gaussian', degauss=0.02 <br>
/<br>&ELECTRONS<br> conv_thr = 1.0d-8 ,<br> mixing_beta = 0.7 ,<br> /<br>ATOMIC_SPECIES<br> C 12.01100 C.pz-vbc.UPF <br> Cu 63.55 Cu.pz-d-rrkjus.UPF<br><br>The celldm(1) and celldm(3), I don't quite understand their meaning and how they came out. Although I could calculate the lattice parameters for carbon nanotube, like the diameter d and the translation parameter t, I still couldn't make connections between these parameters and the values I got here. I forgot how I got them, and now I need to calculate a (8,8) cnt, while I need a larger space between the carbon nanotubes, cause they are now too crowded using the same structure data. I don't know how could I change them.<br>
<br>2. I don't know what kind of pseudopotential I should choose, there are several potentials for each element, while I am just looking for a general calculation. <br>3. I keep the other parameters like the ecutwfc, the conv-thr, and the mixing-beta the same for different metal elements, does that do harm to my calculations? I am not quite sure.<br>
<br>Well, thank you for your time. I know my questions are somehow silly, but hope one could teach me.<br><br>Thanks.<br><br>Regards.<br><br>Chengyu Yang<br>MMAE department, University of Central Florida<br>USA<br><br>