[Wien] error dstart in sm-structure in hexagonal axes

Peter Blaha pblaha at theochem.tuwien.ac.at
Sun Feb 9 10:23:25 CET 2014


Wien2k will by default always use the smallest possible unit cell.

Eg. for a fcc Cu cell (F -attice), you have only one atom (0,0,0), but if you
want to run this in a simple cubic lattice (P lattice, identical lattice parameters),
you would have 4 atoms (+(0.5,0.5,0) and permutations).
However, w2k does NOT allow such a calculation with 4 EQUIVALENT atoms.
If you still want to use a P cell with FOUR atoms, you have to make them
NON_EQUIVALENT. You can do this eg. by naming the atoms  Cu1, Cu2, Cu3 and Cu4.

Now the same happens for your problem. The "R" cell is 3 times smaller than the
"H" setting. If you want to use the H lattice, you must make some/all atoms
non-equivalent by the method explained above.

PS: Do you know "why" you want the H setting ?
It makes only sense for E-tot comparison with different phases (in "real" H-cells)
or when you want to do impurities, vacancies,... (although than the cell is still
too small).

Am 08.02.2014 12:14, schrieb Stefaan Cottenier:
>
>> I want to run sm metal in hexagonal axes, as Prof. Cottenier said, the
>> file struct should be as below;
>
> You asked for the hexagonal information -- which you got. This does define the correct lattice, and wien2k can read/understand this, but cannot work with such a structure
> file as such. As said before (see usersguide), for rhombohedral lattices you have to give the hexagonal lattice constant but rhombohedral coordinates. During init_lapw,
> sgroup will make this conversion for you. If you accept its suggestion (which has only 3 atoms), dstart will run fine.
>
> Stefaan
>
>
>>
>> H   LATTICE,NONEQUIV.ATOMS   2  166 R-3m
>> MODE OF CALC=RELA unit=bohr
>>    6.856115  6.856115 49.573186 90.000000 90.000000120.000000
>> ATOM  -1: X=0.00000000 Y=0.00000000 Z=0.00000000
>>            MULT= 3          ISPLIT=15
>>        -1: X=0.66666667 Y=0.33333333 Z=0.33333333
>>        -1: X=0.33333333 Y=0.66666667 Z=0.66666667
>> Sm         NPT=  781  R0=.000010000 RMT=   2.50000   Z:  62.00000
>> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>>                       0.0000000 1.0000000 0.0000000
>>                       0.0000000 0.0000000 1.0000000
>> ATOM  -2: X=0.00000000 Y=0.00000000 Z=0.22222222
>>            MULT= 6          ISPLIT=15
>>        -2: X=0.66666667 Y=0.33333333 Z=0.55555556
>>        -2: X=0.33333333 Y=0.66666667 Z=0.88888889
>>        -2: X=0.00000000 Y=0.00000000 Z=0.77777778
>>        -2: X=0.66666667 Y=0.33333333 Z=0.11111111
>>        -2: X=0.33333333 Y=0.66666667 Z=0.44444444
>> Sm         NPT=  781  R0=.000010000 RMT=   2.50000   Z:  62.00000
>> LOCAL ROT MATRIX:    1.0000000 0.0000000 0.0000000
>>                       0.0000000 1.0000000 0.0000000
>>                       0.0000000 0.0000000 1.0000000
>>     0      NUMBER OF SYMMETRY OPERATIONS
>>
>>
>> I make this structure, but when i initialized it, the new error in
>> dstart is obsearved as
>> Error in DSTART
>>   'ROTDEF' - no symmetry operation found.
>>   'ROTDEF' - for jatom, index   1   2
>>   'ROTDEF' - atomposition of jatom   0.0000000   0.0000000   0.0000000
>>   'ROTDEF' - atomposition of index   0.6666667   0.3333333   0.3333333
>> Please let me know, how can i solve it?
>>
>>
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>>
>
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-- 
-----------------------------------------
Peter Blaha
Inst. Materials Chemistry, TU Vienna
Getreidemarkt 9, A-1060 Vienna, Austria
Tel: +43-1-5880115671
Fax: +43-1-5880115698
email: pblaha at theochem.tuwien.ac.at
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