[Wien] How to generate the C19 structure (alpha-Sm)?

[Claudio Cazorla Silva]

|Hello,

|did you correctly transform your lattice parameters from rhombohedral 
|to hexagonal by applying the transformations given in the User's Guide, 
|page 40 (in the version of November 2007)?
|Remember that the atomic coordinates, on the other hand, must be 
|supplied in rhombohedral setting. A position like (0, 0 2/9) looks 
|quite bizarre to me, what is the actual coordinate in the original 
|structure?

|Greetings
|Michael



Hello,
the coordinate in the original structure is (0,0,2/9*c_{rhomb}) 
(cartesian), that is
(0,0,sqrt(8/3)*a_{rhomb}). However, if I enter (0,0,sqrt(8/3)) or 
(0,0,2/9) for it in Structgen I
still get nonsense RMT's.

I list below the vectors describing the C19 structure:
Lattice vectors:
*A*_1     =     ½ a *X* - 12^-½ a *Y* + 1/3 c *Z*
*A*_2     =     3^-½ a *Y* + 1/3 c *Z*
*A*_3     =     - ½ a *X* - 12^-½ a *Y* + 1/3 c *Z*

Basis Vectors:
*B*_1     =      0
*B*_2     =     + z (*A*_1 + *A*_2 + *A*_3 )     =     + z c_ *Z* 
*B*_3     =     - z (*A*_1 + *A*_2 + *A*_3 )      =     - z c_ *Z* 

with z = 2/9 and c = 9 * sqrt(2/3) * a.

Any suggestion?
Best regards.
Dr. C. Cazorla Silva