[Pw_forum] input for a polymer crystal

[Jonas Baltrusaitis]

I am trying to optimize a hydrogen bonded polymer crystal structure. I have experimental a,b,c and all three angles of the cell, as well as the point group. Also fractional coordinates

what I don't have is an idea how to prepare an input. I read Doc/Input_pw closely and couldn't find how to utilize any of those (except atomic positions). 

CELL_PARAMETERS should accommodate those somwehow but it's only 3x3 matrix input in the manual instead. also, specifying ibrav, celldm, nat, ntyp and nbnd are not clear as it's nothing like a simple Al or Si structure. also, what do I put for K_POINTS? Gamma only?

thanks for the help

Jonas Baltrusaitis
University of Iowa