<!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>