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<body class='hmmessage'><div dir='ltr'>Dear PWSCF users,<br><br>I have a question regarding vc-relaxation with bfgs. I am trying to optimize lattice parameters and atomic positions of unit cell at high pressures. while initial symmetry of unit cell is tetragonal (a=b), the optimized cell parameters at P=25 GPa seems to be in orthorhombic symmetry i.e., <span style="font-weight: bold;">a </span>and <span style="font-weight: bold;">b</span> lattice parameters are no more equal. Final cell paramteres are:<br><br>CELL_PARAMETER<br><br>0.9958000 0.0000000 0.000000<br>0.0000000 0.9929000 0.000000<br>0.0000000 0.0000000 1.405800 <br><br>Can vc-relaxation at a given pressure with bfgs method allows for change of crystal symmetry ?? I would appreciate a clarification<br><br>with best regards<br><br>Saqib Javaid<br>NCP, Pakistan. <br> </div></body>
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