[Phonopy-users] question about how to enter multiple atoms as symbols

[Amanda S. <co...@gm...>]

Togo,

Regards again! I have been working with phonopy now for the past few weeks
and the examples are working nicely. I have been playing around in the
/example/ase directory. For these examples you have calculated various
properties for Si 8 atom cell. I would like to know how to extend to more
than one atom. In the example script you have:
a = 5.404
bulk = PhonopyAtoms(symbols=['Si']*8,
                    scaled_positions=[(0, 0, 0),
                                      (0, 0.5, 0.5),
                                      (0.5, 0, 0.5),
                                      (0.5, 0.5, 0),
                                      (0.25, 0.25, 0.25),
                                      (0.25, 0.75, 0.75),
                                      (0.75, 0.25, 0.75),
                                      (0.75, 0.75, 0.25)] )


My question is how would I do this for a binary system? For example,
consider SiO2 with 16 positions. I have tried several different things,
including symbols=['Si', 'O']*16 followed by positions, and also have tried
with symbols = ['Si']*8 of Si with Si positions followed by symbols=['O']*8
followed by O positions and I can get neither of these to work. Could you
provide a simple example using the PhonopyAtoms class for binary system
please? I would greatly appreciate it!

Kindest Regards,

-- 
Amanda Stott
Graduate Research and Teaching Assistant
The University of Alabama
Department of Chemistry
Tuscaloosa, AL 35487-0336