PAW augmentation radius

Message

mf081 · #1 Post by **mf081** » Mon Jun 18, 2007 2:45 pm

Hello,

where can I find the value of the augmentation radius in the POTCAR, and in which unit is it written there?

mf081 · #2 Post by **mf081** » Wed Jun 27, 2007 12:28 pm

Can someone please give me answer? There are several numbers written in the POTCAR. Which one gives me the cutoff-radius of the potential and what is the unit? I am doing MD simulations for dense systems, and I would like to know how close the ions can get without overlap of the augmentation spheres, which may cause errors.

#3 Post by **admin** » Thu Jun 28, 2007 9:20 am

the radius of the augmentation sphere is RMAX, it is read from POTCAR (line after "PAW radial sets")

mf081 · #4 Post by **mf081** » Fri Jun 29, 2007 9:03 am

Thank you for your answer. Is it the second number in that line? And in which unit is the value given?

#5 Post by **admin** » Mon Jul 02, 2007 8:03 am

yes, the second number. sorry, the unit of lengths VASP uses throughout is Ã…, I forgot to write that....

mf081 · #6 Post by **mf081** » Mon Jul 02, 2007 12:50 pm

Thank you very much!
Looking at the numbers, I see that the augmentation radius is e.g. for hydrogen larger than half the atomic distance in an H2 molecule. I thought that one should avoid an overlap of the augmentation radius, but it seems I am wrong.
When I perform MD simulations of a very very dense system, VASP gives me a warning that the atoms are too close. Please, can you tell me, from which physical parameter you decide when the atoms are too close?
<span class='smallblacktext'>[ Edited Mon Jul 02 2007, 02:51PM ]</span>