[Pw_forum] CELLDM and atomic positions

[Cristian Rivas]

Gentlemen:

In example #1 the CELLDM value is 10.20 and the atomic positions are
0.00,0.00,0.00 and 0.25,0.25,0.25 for the silicon simulation.  How is the
lattice constant of 5.43 Ang. obtained for this bulk silicon
simulation.  In other words, if I would like to simulate something else
(say germanium), what kind of values do I have to enter in order to
specify the correct lattice constant (for example, 5.65 Ang. for
germanium). 

Cristian