New Pseudopotentials

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askhetan · #1 Post by **askhetan** » Thu Jan 10, 2013 1:14 pm

From the new set of Pseudopotentials provided by VASP, I see that there are many variants for each kind of element. I wanted to know that if accuracy was my main concern, then is it better to use the hard pseudopotentials or the softer ones ? for example for Ce and H atoms.

#2 Post by **admin** » Wed Jan 30, 2013 4:25 pm

these issues have been discussed in the handouts of one of the first VASP-workshops, please download them from the VASP site. The question whether to use a soft or hard PP is quite general

fan27713 · #3 Post by **fan27713** » Fri Feb 08, 2013 11:37 pm

I am still confused about these new pseudopotentials too. Is there any easy way to pick which pp to be used for publication without reviewer telling us it's crap? : ) for example, I know PAW is better ultrasoft, I think it would really help new users is to have a brief history of PP development and a general, plain English explanation of PP without these jargons and fancy formula. Maybe there is one already, can someone kindly point me the link?

Thanks in advance.

<span class='smallblacktext'>[ Edited Sat Feb 09 2013, 12:19AM ]</span>

askhetan · #4 Post by **askhetan** » Sat Feb 09, 2013 5:33 pm

Yes, for almost all cases, PAW is better than US-PP. But when you look at the directory of the PAW pseudopotentials, there are pseudopotentials for some species which come with the annotation "hard". I was curious whether these hard ones are better than the normal ones. they are, but it turns out that they have a very high demand for energy cutoff. so my guess is that even if i try solving in with the normal PAW pseudopotentails but specify good enough cutoff, i won't probably loose so much on accuracy.

fan27713 · #5 Post by **fan27713** » Mon Feb 11, 2013 6:52 am

Thank you, Askhetan, this helps a lot. I was looking at those directories, and noticed there is one call element_sv_GW, do you now what GW is? do you have a reference? Thanks.