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</o:shapelayout></xml><![endif]--></head><body lang=EN-GB link=blue vlink=purple><div class=WordSection1><p class=MsoNormal>Dear all,<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><pre>I am currently performing IRC scans using the QSDPATH method with a CASSCF wavefunction. The normal method as shown in the examples uses a numerical hessian recalculated every 5 updates (numhess=5), but with my system that is *<b>rather</b>* slow. I would like to use analytical hessians as in <span style='color:black'>{multi;cpmcscf,hess}, but after 5 steps the subsequent OPTG for the QSDPATH ignores this hessian and creates a new numerical one. How can i force OPTG to recalculate the hessian every 5 steps, analytically?<o:p></o:p></span></pre><pre><span style='color:black'><o:p> </o:p></span></pre><pre><span style='color:black'>Thanks in advance,<o:p></o:p></span></pre><pre><span style='color:black'>Mike Nix<o:p></o:p></span></pre><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>------------------------------<o:p></o:p></p><p class=MsoNormal>Dr. Mike Nix<o:p></o:p></p><p class=MsoNormal>Lecturer in Physical Chemistry<o:p></o:p></p><p class=MsoNormal>University of Leeds<o:p></o:p></p><p class=MsoNormal>LS7 4QH<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>+44(0)113 343 5960<o:p></o:p></p><p class=MsoNormal>m.g.nix@leeds.ac.uk<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p></div></body></html>