[Pw_forum] unit-printing error?
Karoly Nemeth
nemeth at anl.gov
Sat Mar 21 05:15:05 CET 2009
Hi,
I became aware of some unit printing errors in PWSCF (v.4.0.4). At least
it seems to be case.
In one of my calculations I got:
crystal axes: (cart. coord. in units of a_0)
a(1) = ( 2.556193 0.000000 0.000000 )
a(2) = ( 0.000000 2.556193 0.000000 )
a(3) = ( 0.000000 0.000000 30.000000 )
reciprocal axes: (cart. coord. in units 2 pi/a_0)
b(1) = ( 0.391207 0.000000 0.000000 )
b(2) = ( 0.000000 0.391207 0.000000 )
b(3) = ( 0.000000 0.000000 0.033333 )
Obviously, the reciprocal axes is printed in units of 1/a_0, and not in
"2 pi/a_0". A few lines below in the output, where k-points are listed
I see:
number of k points= 260 gaussian broad. (Ry)= 0.0300 ngauss =
-1
cart. coord. in units 2pi/a_0
k( 1) = ( 0.0000000 0.0000000 0.0000000), wk =
0.0039063
k( 2) = ( 0.0000000 0.0000000 0.0041667), wk =
0.0078125
Comparing reciprocal lattice to the listed k-points, it turns out, that
k-point are also listed in units of 1/a_0, and not in "2pi/a_0".
This seems to be a unit-printing error, as otherwise everything is
consistent. If I remember well, in older versions the unit used to be 1/a_0 .
Please let me know if I am right with the above.
Thanks:
Karoly
***********************************************************************
Karoly Nemeth, Ph.D.
Argonne National Laboratory
9700 S. Cass Ave. Argonne, IL 60439.
Advanced Photon Source
Accelerator Physics and Operations Group
Building 401, Room B2200
Tel. 630-252-5813
Fax: 630-252-4732
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