[Pw_forum] Question regarding celldm input

[Ariadna Blanca Romero]

For example, if you use ibrav=3 (bcc), you must provide the conventional lattice parameter in celldm(1). In case you are running a full relaxation you will get at the end the relaxed primitive lattice vectors from which you can get the primitive lattice parameter.  You can use the relation between the volume of the primitive cell with the  conventional lattice parameter to get the latter (Vol (bcc prim cell)=a_conv^3/2. Hope it helps.

Ariadna