Dear Sir,<br><br>Thank you for your helping hand. I am getting convergence by choosing distances
above 0.9 Ang. However, there is convergence problem for distances less
than or equal to 0.8 Ang. I think, 0.8 or 0.7 Ang is not too small to result in "no convergence". Can the convergence problem at small
distances be eliminated by using cards line WF and CON?<br><br>Thank you<br><br>Sunil<br><br><div class="gmail_quote">On Mon, Jan 26, 2009 at 4:04 PM, Peter Knowles <span dir="ltr"><<a href="mailto:KnowlesPJ@cardiff.ac.uk">KnowlesPJ@cardiff.ac.uk</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div style="">It looks to me as if your calculations nearly converge, and would do so with just a few more iterations in the MCSCF equation solver, which can be specified using the MAXITER command - see <a href="http://www.molpro.net/info/current/doc/manual/node252.html" target="_blank">http://www.molpro.net/info/current/doc/manual/node252.html</a><div>
Of course, 0.4 Angstrom is a very short bond length giving very high ground-state energies, and one can expect all kinds of challenges from low-lying states that might affect the choice of active orbital space.</div><div>
Peter<br><div><div><div></div><div class="Wj3C7c"><div>On 26 Jan 2009, at 05:46, Sunil wrote:</div><br></div></div><blockquote type="cite"><div><div></div><div class="Wj3C7c">Dear Sir,<br><br>I am facing a convergence problem when using Molpro to calculate potential energy surfaces of CO2 molecule. The input of the program is as follows:<br>
<br><br>*** CO2 PE curve ! Title: PE Curve for CO2<br> memory,32,m<br>maxiter=100<br>geomtyp=zmat<br>geometry<br>ang ! ang is used if we intend to provide distance in Angstrom; default for Z-matrix is au<br>
C<br>O1 C rco1(i)<br>O2 C rco2(i) O1 oco<br> end<br><br>r1(1) = 0.400000 Ang<br>r2(1) = 0.400001 Ang<br>dr = 0.1 Ang<br>do i = 1,19<br>r1(i+1) = r1(i)<br>r2(i+1) = r2(i) + dr<br>enddo<br><br>oco = 180 Deg<br><br>basis = vqz ! Basis set specification<br>
<br>do i = 1,20<br><br>rco1(i) = r1(i)<br>rco2(i) = r2(i)<br><br>hf;<br>enhf(i)=energy<br><br>mp2;<br>enmp2(i)=energy<br><br>multi;<br>emcscf(i) = energy<br><br>enddo<br><br>table rco1,rco2,enhf,enmp2,emcscf !emscf !,ecas,emrci<br>
head R1,R2,SCF,MP2,MCSCF<br>save co2_mcscf.tab<br>Title Results for CO2 (Angle = 180 Deg)<br>!sort 3,1,2<br>---<br><br>It produces the output but without convergence for the MCSCF calculations.<br><br>Thank you in advance for any kind of help.<br>
<br>regards<br>Sunil<br></div></div> _______________________________________________<br>Molpro-user mailing list<br><a href="mailto:Molpro-user@molpro.net" target="_blank">Molpro-user@molpro.net</a><br><a href="http://www.molpro.net/mailman/listinfo/molpro-user" target="_blank">http://www.molpro.net/mailman/listinfo/molpro-user</a><br>
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<span style="font-size: 12px;">--</span></div><div style="font-size: 12px;"><span style="font-size: 12px;">Prof. Peter J. Knowles </span></div><div style="font-size: 12px;"><span style="font-size: 12px;">School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK</span></div>
<div style="font-size: 12px;"><span style="font-size: 12px;">Telephone: +44 29208 79182 Fax: +44 2920874030 Email <a href="mailto:KnowlesPJ@Cardiff.ac.uk" target="_blank">KnowlesPJ@Cardiff.ac.uk</a> </span></div><div style="font-size: 12px;">
<span style="font-size: 12px;">WWW <span style="font-size: 13px;"><a href="http://www.cardiff.ac.uk/chemy/contactsandpeople/academicstaff/knowles.html" target="_blank">http://www.cardiff.ac.uk/chemy/contactsandpeople/academicstaff/knowles.html</a></span></span></div>
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