[Wien] P and H differences

[Franco Jona]

wien at zeus.theochem.tuwien.ac.at
                              28 July 2004
Dear All,

   I want to compare energies between different lattice structures, and
I need high accuracy. But when I cross-check the *same* lattice structure
with different but equivalent case.struct-files, I find differences that
are already larger than I can tolerate.  I append a sample struct file:
running it either with the P lattice or with the H lattice produces
energy differences of 7 to 10 mRy !

   I tested this extensively for k-mesh and basis set size.
Is there another parameter to consider? Or is this an unsurmountable
accuracy limit, which would be very bad news indeed ....

   Can anybody please make a suggestion?  Thank you very much.

   Franco Jona

P.S. Here is one struct file:

Mo
P   LATTICE,NONEQUIV.ATOMS:  2
MODE OF CALC=RELA unit=bohr
  5.210000  5.210000  9.310000 90.000000 90.000000120.000000
ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
          MULT= 1          ISPLIT= 8
Mo1        NPT=  781  R0=0.00010000 RMT=    2.0000   Z: 42.0
LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
                     0.0000000 1.0000000 0.0000000
                     0.0000000 0.0000000 1.0000000
ATOM  -2: X=0.66666667 Y=0.33333333 Z=0.50000000
          MULT= 1          ISPLIT= 8
Mo2        NPT=  781  R0=0.00010000 RMT=    2.0000   Z: 42.0
LOCAL ROT MATRIX:    0.0000000 0.0000000 0.0000000
                     0.0000000 0.0000000 0.0000000
                     0.0000000 0.0000000 0.0000000
   0      NUMBER OF SYMMETRY OPERATIONS