<html dir=""><head><style id="axi-htmleditor-style" type="text/css">p { margin: 0px; }</style></head><body style="font-size: 10pt; font-family: Arial; background-image: none; background-repeat: repeat; background-attachment: fixed;">Thank you dear Tran.<br><br>It was completely helpful.But what is the role of symmetry in calculating cohesive energy as you said reduce cubic to orthorhombic for open shell atoms.Also for Na which is open sell, you use P instead of orthorhombic.<br><br></body></html>