<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
<title></title>
</head>
<body bgcolor="#ffffff" text="#000000">
Dear MJ Wu,<br>
<br>
most likely the problem you face is due to the extremely low
harmonic frequency of 7.5 cm-1. In the harmonic frequency program
Molpro has the peculiarity to separate low frequencies from the
rest. Once this happens only a subset of harmonic frequencies will
be passed to the SURF program, which then may cause strange effects.
You may avoid this by providing the option "low=5.0" to the harmonic
frequency calculation. Besides this, a frequency of just 7.5 cm-1
may cause you severe trouble within the generation of the PES. You
need also to be aware that your current input most likely will
perform more than 100.000 MCSCF single-point calculations. Once you
know the CPU time needed for one point you can easily estimate the
time for generating the entire PES.<br>
<br>
Best wishes,<br>
<br>
Guntram<br>
<br>
<br>
On 08/14/2013 07:06 PM, Kenny W wrote:
<blockquote cite="mid:BAY172-W23BDAE2B13EE2380D71230B7450@phx.gbl"
type="cite">
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 12pt;
font-family:Calibri
}
--></style>
<div dir="ltr">Dear Molpro Experts,
<div><br>
</div>
<div>I tried to perform a VSCF/VCI calculation for a nine-atom
anion in the doublet state, after the geometry optimization
followed analytic frequency at MCSCF level. The frequencies
reported were all positive values, however, the subsequent 1D
SURF calculation complained about imaginary frequency and
could not continue.</div>
<div><br>
</div>
<div>First, the MCSCF OPTG and FREQUENCY calculation keywords
are shown as follows:</div>
<div><br>
</div>
<div>
<div><b>NOSYM;</b></div>
<div><b>orient,mass</b></div>
<div><b>mass,iso</b></div>
<div><b>basis={default=aug-cc-pwCVDZ}</b></div>
</div>
<div><b><br>
</b></div>
<div>
<div><b>{multi,energy=1.0e-8,gradient=1.0e-5,step=1.0e-5</b></div>
<div><b>maxiter,40</b></div>
<div><b>occ,50;closed,37; !CAS(13,13)</b></div>
<div><b>wf,87,1,1;</b></div>
<div><b>natorb,print=20,ci,state=1.1}</b></div>
<div><b><br>
</b></div>
<div><b>{optg,maxit=100,gradient=1.0e-5,energy=1.0e-8,step=1.0e-5}</b></div>
<div><b>pop;</b></div>
<div><b><br>
</b></div>
<div><b>{multi,energy=1.0e-8,gradient=1.0e-5,step=1.0e-5;cpmcscf,hess,accu=1.d-5</b></div>
<div><b>maxiter,40</b></div>
<div><b>occ,50;closed,37; </b></div>
<div><b>wf,87,1,1;</b></div>
<div><b>natorb,print=10,ci,state=1.1}</b></div>
<div><b><br>
</b></div>
<div><b>{frequencies,analytical</b></div>
<div><b>print,hessian,low}</b></div>
<div><b><br>
</b></div>
<div><b>put,molden,cas1313_awcdz_nosym_optfrq.molden;</b></div>
</div>
<div><b>---</b></div>
<div><br>
</div>
<div>and the reported frequencies (all positive) are:</div>
<div><br>
</div>
<div>
<div> <b>_FREQUENCIES(1:27) = 0.00001845 0.00001629
0.00000707 0.00000225 0.00001146
0.00001581</b></div>
<div><b> 7.52426274 58.84544984
64.37850876 70.83457530 103.14123353
126.11691779</b></div>
<div><b> 137.75677617 181.48189951
234.48735837 270.42956902 345.45378008
427.77056976</b></div>
<div><b> 461.65694834 524.95228098
531.51838006 575.23162819 586.87961440
1633.71618449</b></div>
<div><b> 1637.44993389 1999.82375492
2062.79045692</b></div>
</div>
<div><br>
</div>
<div>The second step was to calculate VSCF and VCI by restarting
from the files 1 and 2 of the previous calculation:</div>
<div><br>
</div>
<div>
<div><b> restart;</b></div>
<div><b> file,1,vscf.int</b></div>
<div><b> file,2,vscf.wfu</b></div>
<div><b> file,3,vscf.res,new</b></div>
</div>
<div>
<div><b>NOSYM;</b></div>
<div><b>orient,mass</b></div>
<div><b>mass,iso</b></div>
<div><b>basis={default=aug-cc-pwCVDZ}</b></div>
</div>
<div><b><br>
</b></div>
<div>
<div><b>label1</b></div>
<div><b>{multi,energy=1.0e-8,gradient=1.0e-7,step=1.0e-5</b></div>
<div><b>maxiter,40</b></div>
<div><b>occ,50;closed,37;</b></div>
<div><b>wf,87,1,1;</b></div>
<div><b>state,1</b></div>
<div><b>natorb,2141.3,state=1.1</b></div>
<div><b>cpmcscf,grad,1.1,accu=1.d-9}</b></div>
<div><b><br>
</b></div>
</div>
<div>
<div><b>{surf,start1D=label1,ndim=3,dellog=1,sym=auto !(3)
generate PES</b></div>
<div><b>scalnm,auto=on</b></div>
<div><b>intensity,dipole=2}</b></div>
<div><b><br>
</b></div>
<div><b>vscf </b></div>
<div><b>vci,pmp=3,version=1 </b></div>
<div><b>vci,pmp=3,version=2</b></div>
</div>
<div><b>---</b></div>
<div><br>
</div>
<div>The job bump out at SURF program, with the final dying
message:</div>
<div><br>
</div>
<div><b> You have an imaginary vibration. Please check the FREQ
calculation.</b></div>
<div><br>
</div>
<div>However in the previous job all of the harmonic frequencies
were found positive. May I know what was wrong with my SURF
input? Thank you very much for your kind attentions.</div>
<div><br>
</div>
<div>==========</div>
<div>MJ Wu</div>
</div>
<pre wrap="">
<fieldset class="mimeAttachmentHeader"></fieldset>
_______________________________________________
Molpro-user mailing list
<a class="moz-txt-link-abbreviated" href="mailto:Molpro-user@molpro.net">Molpro-user@molpro.net</a>
<a class="moz-txt-link-freetext" href="http://www.molpro.net/mailman/listinfo/molpro-user">http://www.molpro.net/mailman/listinfo/molpro-user</a></pre>
</blockquote>
<br>
<pre class="moz-signature" cols="72">--
********************************************************************************
Prof. Dr. Guntram Rauhut
Institut f. Theoretische Chemie
Universitaet Stuttgart
Pfaffenwaldring 55
D-70569 Stuttgart
Germany
Tel. : +49/(0)711/685-64405
FAX : +49/(0)711/685-64442
E-Mail : <a class="moz-txt-link-abbreviated" href="mailto:rauhut@theochem.uni-stuttgart.de">rauhut@theochem.uni-stuttgart.de</a>
HTTP : <a class="moz-txt-link-abbreviated" href="http://www.theochem.uni-stuttgart.de/~rauhut/">www.theochem.uni-stuttgart.de/~rauhut/</a>
********************************************************************************
</pre>
</body>
</html>