<HTML><BODY>Hello, molpro users and developers.<br><br>I met a rather strange result: <br>uccsd(t) calculation for a Cs atom did not converge,<br>when I used dhf-qzvp-2c basis set. <br><br>So, the ending of the output file was as following:<br><br> ? Error<br> ? No convergence. This error exit can be avoided using the NOCHECK option<br> ? The problem occurs in ccsd<br><br>Here is the code (I also attached the appropriate input file to this mail):<br>***<br>gthresh,energy=1.d-8,orbital=1.d-8,coeff=1.d-7<br>....<br>symmetry,x,y<br>geometry={Cs}<br>{rhf;occ,3,1,1,0;core,0,0,0,0;wf,9,1,1;}<br>{uccsd(t);core,0,0,0,0;wf,9,1,1;}<br>...<br><br>I should note, that the dhf-qzvp-1c set converges in such calculation (you can run the attached input file - it contains both sets).<br>And, by the way, the difference between -1c and -2c set is only in two
p-functions, which are added to take into account spin-orbit effects.<br>Of course, I see that the result depends on global thresholds [so, calculations with dhf-qzvp-2c set converge for bigger thresholds; <br>for instance with: gthresh,energy=1.d-6,orbital=1.d-5,coeff=1.d-5 ]. <br>But it still seems to be strange, that almost the same basis set doesn't converge in the <br>same routine.<br><br>I use molpro2010, so I take dhf basis sets here: <a href="http://www.cosmologic.de/basis-sets/basissets.php" target="_blank">http://www.cosmologic.de/basis-sets/basissets.php</a><br><br>Alexander Medvedev,<br>student of the 5th course,<br>MSU, Chemistry Department,<br>Chair of laser chemistry<br></BODY></HTML>