[Pw_forum] matdyn file output

[Paolo Giannozzi]

Denny Jackson wrote:

> Also, each column should add up to zero to preserve symmetry, 
> should it not?

not necessarily. Acoustic modes at Gamma are rigid translations
and do not add up to zero

> For higher frequencies in this calculation the columns do indeed 
> add up to zero, but for lower frequencies (and negative frequencies) 
> this is not the case. 

see above: this is the expected behavior

> Is there a resource for good documentation on the matdyn file

no, but there are various utilities that read the force constants
or dynamical matrix file, produce whatever you need. It is much
easier to figure out what these codes do than to figure out
the exact file format

P.
-- 
Paolo Giannozzi, Democritos and University of Udine, Italy