Dear professor Werner and colleagues,<div><br></div><div>I see the point, but it's not the case. </div><div><br></div><div>I have converged the geometry and calculated the frequencies both using symmetry (in which I froze the dihedral coordinate - my molecule has 4 atoms, and this particular isomer is planar) or not, and normal modes confirm that I have a TS (no warning message regarding gradient norms). It's true that when it's optimized without symmetry, the dihedral plane is not exactly zero (the value when symmetry is on), but it's lower than 1 degree, and frequencies are essentially the same.</div>
<div><br></div><div>Regards,</div><div><br></div><div>Gabriel</div><div><br></div><div><br><br><div class="gmail_quote">2012/1/9 Hans-Joachim Werner <span dir="ltr"><<a href="mailto:werner@theochem.uni-stuttgart.de">werner@theochem.uni-stuttgart.de</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div style="word-wrap:break-word">This can happen if you optimize the transition state in a limited parameter space.<div>
The IRC optimization requires a full optimization (3N-6 coordinates). Please check </div><div>if that is the case!</div><div>Best regards</div><div>Joachim Werner <br><div><div>Am 08.01.2012 um 16:30 schrieb Gabriel Freitas:</div>
<br><blockquote type="cite"><div><div class="h5">Dear molpro users/developers,<div><br></div><div>I'm trying to do an IRC calculation from a transition state previously calculated. But by the time the qsdpath takes its first step, I get the message:</div>
<div><br></div>
<div><i>QSDPATH2: Starting point is not a critical point.</i></div><div><br></div><div>I've tried many things, but unsuccessfully, and I'm afraid there can be a bug in the code.</div><div><br></div><div>Here follows one example, in which I reoptmize the TS (which converges in a single step, since the starting geometry is already converged) and ask for IRC using the hessian calculated during the TS search.</div>
<div><br></div><div><br></div><div>Part of the input</div><div><br></div><div>XXXXXXXXXXXX</div><div><div> nosym</div><div> R1=1.34210982 ang,</div><div> R2=1.76235720 ang,</div><div> R3=1.30142476 ang,</div><div> a=92.77261716 degree,</div>
<div> b=113.97606866 degree,</div><div> g=0.00000 degree</div><div> geometry={ }</div><div> rhf,maxdis=50,maxit=100;</div><div> rccsd(t),maxit=70;</div><div> {optg,root=2,method=qsd,maxit=100,saveact=...,rewind;print,history}</div>
<div> {optg,method=qsdpath,hessrec=5300.2,dir=+3,numhess=0,hesscentral,maxit=100;print,history}</div><div><br></div><div>XXXXXXXXXXXXXXX</div><div> </div></div><div><b><i>Part of the output</i></b></div><div><br></div><div>
XXXXXXXXX</div><div><br></div><div><div> PROGRAM * OPT (Geometry optimization) Authors: F. Eckert and H.-J. Werner</div><div><br></div><div> Geometry optimization using default procedure for command RCCSD(T)</div><div>
<br></div><div> Numerically approximating hessian using central energy differences</div><div><br></div><div> Task list generated. Total number of displacements: 42</div><div> </div><div> .... </div><div><br></div><div>
Numerical RCCSD(T) hessian completed. CPU-time: 31364.93 sec, Elapsed: 33653.29 sec</div><div><br></div><div> RCCSD(T) hessian saved to record 5300.2</div><div><br></div><div> Combined Powell-Murtagh-Sargent Update of Hessian</div>
<div><br></div><div> Quadratic Steepest Descent - Transition State Search</div><div><br></div><div> Optimization point 1</div><div><br></div><div> Variable Last Current Next Gradient Hessian</div>
<div><br></div><div> E(RCCSD(T)) / Hartree 0.00000000 -548.43957924 0.00000000</div><div> R1 / ANG 0.00000000 1.34210982 1.34215444 -0.00004976 0.97545936</div><div> R2 / ANG 0.00000000 1.76235720 1.76307008 -0.00025977 0.46872502</div>
<div> A / DEGREE 0.00000000 92.77261716 92.75401930 0.00000022 0.00006113</div><div> R3 / ANG 0.00000000 1.30142476 1.30118943 0.00017736 1.53165483</div>
<div>
B / DEGREE 0.00000000 113.97606866 113.97094779 0.00000020 0.00009433</div><div> G / DEGREE 0.00000000 0.00000000 -0.06878260 0.00000000 0.00000090</div><div>
Convergence: 0.00000000 (line search) 0.00189055 0.00016936 (total)</div>
<div><br></div><div> END OF GEOMETRY OPTIMIZATION. TOTAL CPU: 31240.2 SEC</div><div><br></div></div><div><br></div><div><div> PROGRAM * OPT (Geometry optimization) Authors: F. Eckert and H.-J. Werner</div><div>
<br></div><div><br></div><div> Geometry optimization using default procedure for command RCCSD(T)</div><div><br></div><div><br></div><div> Number of displacements for numerical gradient: 12</div><div><br></div><div> Starting numerical gradient for RCCSD(T)</div>
<div><br></div><div> Numerical gradient completed. CPU-time: 8776.29 sec, Elapsed: 9365.30 sec</div><div><br></div><div> RCCSD(T) hessian read from record 5300.2</div><div><br></div><div> Combined Powell-Murtagh-Sargent Update of Hessian</div>
<div><br></div><div> Quadratic Steepest Descent - Reaction Path Following using updated Hessian</div><div><br></div><div> Hessian eigenvalues: 0.002870 0.102644 0.198864 0.270747 0.292713 0.478791</div><div><br>
</div><div> QSDPATH2: Starting point is not a critical point.</div><div> Performing a regular QSD step. Stepsize = 0.075068 Curvature = .49831D+04</div><div><br></div><div> Optimization point 1</div><div><br></div><div>
Variable Last Current Next Gradient Hessian</div><div><br></div><div> E(RCCSD(T)) / Hartree 0.00000000 -548.43957912 0.00000000</div><div> R1 / ANG 0.00000000 1.34215444 1.34215192 -0.00000415 0.97545936</div>
<div> R2 / ANG 0.00000000 1.76307008 1.76311166 -0.00002081 0.46872502</div><div> A / DEGREE 0.00000000 92.75401930 92.75259887 0.00000000 0.00006113</div>
<div>
R3 / ANG 0.00000000 1.30118943 1.30117610 0.00000355 1.53165483</div><div> B / DEGREE 0.00000000 113.97094779 113.97050327 -0.00000001 0.00009433</div><div>
G / DEGREE 0.00000000 -0.06878260 -0.14458311 0.00000007 0.00000090</div>
<div> Convergence: 1.00000000 (line search) 0.00132580 0.00001209 (total)</div><div><br></div></div><div>XXXXX</div><div><br></div><div>Although the hessian is calculated for a geometry slightly displaced from the one used for the gradient calculation, it can be seen that both gradients are smaller than the default converge threshold,</div>
<div><br></div><div>Any help would be very appreciated.</div><div><br></div><div>Regards,</div><div><br></div><div>-- <br>Gabriel do Nascimento Freitas<br>D.Sc. Student - Graduate Program of Chemistry<br>Molecular Modelling and Theoretical Chemistry Laboratory - Room 412<br>
Chemistry Institute - Universidade Federal do Rio de Janeiro (UFRJ) - Brazil <br><a href="tel:%28%2B5521%298830-9971" value="+552188309971" target="_blank">(+5521)8830-9971</a> / <a href="tel:%28%2B5521%292562-7179" value="+552125627179" target="_blank">(+5521)2562-7179</a><br>
</div></div></div>
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</blockquote></div><br></div></div></blockquote></div><br></div>