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<body class='hmmessage'><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></body>
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