<html dir="ltr"><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;">​dear wien2k users<br><br>I want to run c/a optimization (constant volume) on a compound which its origin structure is cubic now i have some questions:<br> <br> 1- I know its cubic spacegroup but for c/a optimization in StructGen, i must create its tetragonal structure or cubic space group is correct and just changing the c parameter arbitrary? And is there any further consideration?<br><br>2- 3% Rmt reduction is enough?<br>3- Is there any paper to help me in details about this problem. <br><br><br>excuse me if i ask a simple question.I am a new man. I read some papers but i was not sure about this.<br><br>Thank you in advance</body></html>