I am performing a basic Density functional theory calculation on a simple BCC unit cell using Quantum Espresso. I am curious if it is possible to change/relax only one coordinate, let's say z coordinate of the body-centred atom in the unit cell while keeping all the other coordinates and cell parameters fixed. Also, "relax" calculation with "bfgs" ion_dynamics will optimize all the coordinates. I am fairly new to DFT and so maybe this is just a very basic problem but I can't seem to find the solution anywhere. Can you suggest a way to do that?
Thanks!