Why does my unit cell change with constraints when a Ultra-Fine single point calculation is done in CASTEP
I Used CCDC crystallographic data, optimised Hydogen positions with D3Mol of the Mof-5 Unit cell. Thereafter, I did a medium-energy single-point calculation in CASTEP, followed by an Ultra-Fine single-point energy calculation in CASTEP.
However, A soon as I use an higer energy cutoff (Ultra-fine) my unit cell parameters are changed, even though I have tried constraining atomic and lattice parameters
Why does the program go to higher symmetry when I instructed P1?