<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=koi8-r">
<META content="MSHTML 6.00.2800.1106" name=GENERATOR>
<STYLE></STYLE>
</HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT size=2>Dear all</FONT></DIV>
<DIV><FONT size=2>I am calculating electronic structure of isolated benzene
molecules (C6H6)</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I have managed to run SCF cycles with the values of
</FONT></DIV>
<DIV><FONT size=2>convergence paramerters: charge convergence 0.01 electron
charge,</FONT></DIV>
<DIV><FONT size=2>and NPT (struct gen) 61and</FONT></DIV>
<DIV><FONT size=2>number of points for kgen 61</FONT></DIV>
<DIV><FONT size=2>(RKMAX was 3 and 4 and 5)</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Under these conditions covergence was reached after 10-15
cycles. These values seem to provide faster calculations, but I suspect they
also serve for inaccuracy. </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>I have read a recommendation on 381*2 NPT value for TiC
example and a faq on that for larger supercell even 1 point for kgen may be
enough. </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Please recommend:</FONT></DIV>
<DIV><FONT size=2>Which one of the convergence parameters shall I choose
for small organic molecules (such as benzene) and how much should it
be?</FONT></DIV>
<DIV><FONT size=2>How namy points in structgen /NPT as they are to be assigned
for each atom/ shall I choose for this case?</FONT></DIV>
<DIV><FONT size=2>How many points as an input for kgen shal I
choose?</FONT></DIV>
<DIV><FONT
size=2>
</FONT></DIV>
<DIV><FONT size=2>/in order to make, let's say, a realistic calculation (not
necessary a perfect one for now) </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>----Thanks in advance-----</FONT></DIV>
<DIV><FONT size=2>Alexei Komolov</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2></FONT> </DIV></BODY></HTML>