On Oct 8, 2010, at 22:05 , Daryl Chrzan wrote:
> I still believe that there are 2 atoms per unit cell in the beta-Sn
> structure, so I am a bit confused by your final statement
>
don't take it too seriously: I interpreted the "4a" positions
mentioned in
Not quite:
celldm(1) =11.15433936, celldm(3) =0.54170527
On 10/08/2010 03:55 PM, Daryl Chrzan wrote:
> Michael,
>
> Thank you for the response. I agree that I am far from the minimum.
> However, when I do get to the minimum, I end up with a c/a ratio that is far
> off, and an energy
Paolo,
The smearing flag solved the problems. Thank you much for the tip (on behalf
of myself and my class). I agree this is an excellent teaching exercise. Mark
Asta suggested it to me, and it seems perfect.
I still believe that there are 2 atoms per unit cell in the beta-Sn structure,
so
Michael,
Thank you for the response. I agree that I am far from the minimum. However,
when I do get to the minimum, I end up with a c/a ratio that is far off, and an
energy difference of 0.6 eV, about twice what you find. (I have, I believe,
accounted for the proper number of atoms, etc.)
Daryl Chrzan wrote:
> smearing = 'gaussian',
> degauss = 0.02,
you need occupations='smearing' as well, or else the code
will silently default to fixed occupations. There should
be a check and a warning, but there isn't any. Using QE in
teaching is a great way to find all kinds of problems.
I
Dear Prof Daryl !
Can you please attach your VASP file also so that
I can have a closer look at your VASP file. In fact I did the calculation
with your input file and after optimizing the structure I was getting the
energy difference of 0.69 ev/atom. I just wanted to see
Dayrl,
Looking at your output, it seems that you are very far from the minimum
energy beta-Sn structure:
entering subroutine stress ...
total stress (Ry/bohr**3) (kbar) P=
42.95
0.00079257 0. 0. 116.59 0.00 0.00
0.
Input files were stripped on the previous message. Here they are as part of
the message:
Diamond Cubic:
calculation='scf'
restart_mode='from_scratch',
prefix='silicon',
tstress= .true.
tprnfor= .true.
pseudo_dir='/Users/darylchrzan/ResearchProjects/PSEUDOS/',
Colleagues,
I am working through a problem that I have assigned to my Computational
Materials Science class - computation of the transition pressure for the
diamond-cubic to beta-Sn structures in diamond using pw.x. The problem I have
is that pw.x produces answers that are inconsistent with
