Dear Adebayo Abdulganiy there is no magic. what you need to know are the positions of all the atoms in your unit cell and the three fundamental lattice vectors that define the cell. If you do not have this information there is no way you can build the structure. Once you have it, the cell shape can be defined using the ibrav and celldm variables (see their definitions) or choosing ibrav=0 and explicitly giving the three vectors. The positions can be defined using carthesian coordinates (in bohr, angstrom or unit of celldm(1)) or crystal coordinates (that is as fractions of the three fundamental vectors defining the cell). Read the explanation given about the ATOMIC_POSITION card.
stefano Abolore Musari wrote: > Dear QE user > Pls I need to know how the atomic positions of the system used in the > examples like Si, SiO2 e.t.c are gotten so that i can apply it for the > material i would like to work on. In fact i would appreciate a detail > explanation on this ccos I visited bilbao Crystallographic server and still > couldnt get a clue on how to explore the website. > > thanks > > Adebayo Abdulganiy > university of Ibadan > Nigeria > > > ------------------------------------------------------------------------ > > _______________________________________________ > Pw_forum mailing list > Pw_forum at pwscf.org > http://www.democritos.it/mailman/listinfo/pw_forum >
