<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">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">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>On 26 Jan 2009, at 05:46, Sunil wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">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> _______________________________________________<br>Molpro-user mailing list<br>Molpro-user@molpro.net<br>http://www.molpro.net/mailman/listinfo/molpro-user<br></blockquote></div><br><div> <span class="Apple-style-span" style="border-collapse: separate; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; orphans: 2; text-align: auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-border-horizontal-spacing: 0px; -webkit-border-vertical-spacing: 0px; -webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0; "><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div style="font-size: 12px; "><span class="Apple-style-span" style="font-size: 12px; ">--</span></div><div style="font-size: 12px; "><span class="Apple-style-span" style="font-size: 12px; ">Prof. Peter J. Knowles </span></div><div style="font-size: 12px; "><span class="Apple-style-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 class="Apple-style-span" style="font-size: 12px; ">Telephone: +44 29208 79182 Fax: +44 2920874030 Email KnowlesPJ@Cardiff.ac.uk </span></div><div style="font-size: 12px; "><span class="Apple-style-span" style="font-size: 12px; ">WWW <span class="Apple-style-span" style="font-size: 13px; ">http://www.cardiff.ac.uk/chemy/contactsandpeople/academicstaff/knowles.html</span></span></div><br class="Apple-interchange-newline"></span></span></span></span></div></span> </div><br></div></body></html>