<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 all <br> <br>I am working on Mn2NbAs compound. I can volume optimize the structure successfully and then obtain equilibrium lattice parameter. But i have a problem when i want to run the compound with the equilibrium lattice parameter. actually the charge convergence fluctuate around 0.02 and changes and after more than 250 iteration do not converge. Also i used the following command:<br> runsp_lapw -cc 0.0001 -i 3000 -NI<br><br>How could it possible that the volume optimizatiation consisting of several isolated volume can converge but for one running program it dos not work.<br></body></html>