Dear Nicolas, we were using the pp for silver from this article by Rivero etal and found that the plasmonic resonance disappears.
http://iopscience.iop.org/article/10.1088/0953-8984/28/21/214001/meta be careful. >From the other hand, the normal TM pp for GGA or LDA work well. Best regards, Peter On Tue, Jun 20, 2017 at 7:23 PM, Nicolas Anton Duchêne < [email protected]> wrote: > Dear SIESTA users, > > I've used pseudopotentials (PP) and basis sets (BS) from an article > published in 2015 (Systematic pseudopotentials from reference eigenvalue > sets for DFT calculations, url : http://www.sciencedirect.com/s > cience/article/pii/S0927025614007940#f0005 ) > > In table 1, one finds parameters (radius cut-off values and core > corrections) to be passed on to atom, to create norm-conserving > troullier-martins PPs. > In table 2 there are cut-off parameters for BSs that were found while > optimizing the PP/BS choice. > > In my calculations I am using Ag, with a PBE functional. Here are the two > rows pertaining to Ag, from table 1 and table 2: > PP : Ag (47) 5s14d10 2.19(5s), 2.83(5p), 2.40(4d), 2.82(4f), 0.010, > 0.000 > BS : Ag (47) 5.777, 4.704(5s), 3.637, 3.137(4d), 6.514(5p) > > Here is my PAO.Basis block: > %block PAO.Basis > Ag 4 > n=5 0 2 > 5.777 4.704 > n=5 1 1 > 6.514 > n=4 2 2 > 3.637 3.137 > n=4 3 1 > 2.79 > %endblock PAO.Basis > > > I have three questions : > 1. Relating to the PP : My input contains the parameters indicated by the > article, but the output indicates slightly different parameters (2.17 > instead of 2.19, 2.82 instead of 2.83, 2.40, 2.79 instead of 2.82). I > suppose that this is normal, and shouldn't affect my calculations. Am I > correct? > > 2. Relating to the BS: The article doesn't provide any cut-off radius for > the 4f orbital, and siesta complains if I don't provide it (since the PP is > generated with the 4f information). I didn't know what to put in, so I set > it to 2.79 arbitrarily. I suppose that I should vary this parameter and > verify that I get decent results for an Ag crystal. However, the resulting > lattice parameter after a CG MD run is quite close to the one provided in > the article : 4.049 Ang instead of 4.014 Ang (article value). Furthermore, > the band structure I obtain is the same as in the article. Do you think I > should spend time and ressources trying to fix this discrepancy? > > 3. I will be studying Ag nanoparticles, and have read an article (Optimal > strictly localized basis sets for noble metal surfaces, url: > https://journals.aps.org/prb/pdf/10.1103/PhysRevB.79.075441) discussing > the use of fictitious diffuse s orbitals on surface atoms (which comprise > most of the nanoparticle in small cases). How does one include such an > orbital? Do I simply add the lines > ' n=6 0 1 > 4.76 ' > to my Basis block? > > I realize that these questions may be a bit vague, but I would appreciate > any feedback, comments, or hints/tips. > > Thanks a bunch, > Nicolas Duchêne > Masters Student in Applied Science, Polytechnique Montréal. > > >
