<table cellspacing="0" cellpadding="0" border="0" ><tr><td valign="top" style="font: inherit;">Dear Wien Users,<br>I am a new user and doing some calculation about afm. I have read the UG and FAQ and searching ML. it seems to me that there is not enough information about afm calculations. Could anyone please give me the responce of the following Qs. or show me a reference for more study?<br>1- what is the criteria for making a case.struct _supergroup in general? <br>2-how to find the proper symetry operation matrices for any case if we are not able to find the prper supergroup?<br>3-what is the forth column in the symetry operation matrice which has been used in UG for bcc Cr ( i. e. 0.50 0.5 0.5)?<br> Regards,<br>M. Hezary,<br><br></td></tr></table><br>