<HTML><BODY style="word-wrap: break-word; -khtml-nbsp-mode: space; -khtml-line-break: after-white-space; ">Dear All,<DIV><BR class="khtml-block-placeholder"></DIV><DIV> I am trying to use the RS2 gradient program to computed state-averaged CASSCF gradients using the NOEXC option. In particular, I am trying to compute the gradient of the first excited state in a state averaged calculation - note that the states are "relatively" close in energy. The CASSCF calculation converges but when I call the RS2 module, I get the following error (I attach part of the input file below):</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV> wrong ci coefficient: 1101 6.787851797470805E-002</DIV><DIV> 6.807053294665716E-002</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV> ERROR EXIT</DIV><DIV> CURRENT STACK: CIPRO MAIN</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>So there appears to be some sort of root flipping (maybe ?). It is unclear to me why this will occur as I thought the RS2,NOEXC would provide/use the CASSCF results. Any insights into the cause of the problem or options/suggestions to clear up the problem, would be greatly appreciated.</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Thanks,</DIV><DIV>Alex</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Here is a snippet from my input file (I can send the whole input file if needed):</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>basis=avdz</DIV><DIV> {hf;wf,34,1,0}</DIV><DIV> {multi;occ,20;closed,10;maxiter,100;wf,34,1,0;state,4;start,2100.2;canonical}</DIV><DIV>{rs2;noexc;maxiter,100,300;wf,34,1,0;state,1,2}</DIV><DIV> forces</DIV><DIV><BR class="khtml-block-placeholder"></DIV><DIV>Yes, there are reasons why it is C1 symmetry and I'd be happy to explain in case anyone really wants to know.</DIV><DIV><BR><DIV> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Alex Brown</FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Assistant Professor<SPAN class="Apple-converted-space"> </SPAN></FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Department of Chemistry</FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">University of Alberta</FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">Edmonton, AB</FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica">T6G 2G2</FONT></P> <P style="margin: 0.0px 0.0px 0.0px 0.0px"><FONT face="Helvetica" size="3" style="font: 12.0px Helvetica"><A href="http://www.chem.ualberta.ca/~abrown/">http://www.chem.ualberta.ca/~abrown/</A></FONT></P> </DIV><BR></DIV></BODY></HTML>