<html><head><meta http-equiv="Content-Type" content="text/html charset=utf-8"><meta http-equiv="Content-Type" content="text/html charset=utf-8"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">Dear all,<div class=""><br class=""></div><div class="">I am trying to perform a rather large CASSCF calculations (14 electrons in 14 orbitals) for a transition metal complex, including 10 lowest states in one symmetry and spin: </div><div class=""><br class=""></div><div class="">{multi<br class="">occ,59,51<br class="">closed,45,51<br class="">wf,206,1,2<br class="">state,10<br class="">start,2140.2<br class="">natorb,2140.2</div><div class="">{iterations;do,uncouple,1,to,40;}<br class="">{iterations;dont,internal,1,to,40;}</div><div class="">maxiter,40</div><div class="">}</div><div class=""><br class=""></div><div class="">I have tested many options (see below), but in all cases the iteration procedure in MULTI does not converge and behaves more-or-less like this:</div><div class=""><br class=""></div><div class=""><div class=""> ITER. MIC NCI NEG ENERGY(VAR) ENERGY(PROJ) ENERGY CHANGE GRAD(0) GRAD(ORB) GRAD(CI) STEP TIME<br class=""> 1 5 10 0 -2888.65831267 -2888.65899661 -0.00068394 0.10401421 0.00142009 0.00005114 0.25D-01 2072.98<br class=""> 2 5 12 0 -2888.65911248 -2888.65914897 -0.00003649 0.01727313 0.00183752 0.00000071 0.75D-02 4633.39<br class=""> 3 5 13 0 -2888.65916089 -2888.65916485 -0.00000396 0.00551549 0.00172582 0.00000027 0.29D-02 7129.37<br class=""> WARNING: exit with wrong ci vector!!<br class=""> 4 9 13 780 -2888.50043310 -2888.50276409 -0.00233099 0.14909468 0.00149085 0.00000018 0.32D+00 9365.53<br class=""> 5 4 11 0 -2888.65301376 -2888.65853076 -0.00551701 0.12042313 0.00264229 0.00004756 0.26D+00 11419.07<br class=""> 6 4 11 0 -2888.65895997 -2888.65913627 -0.00017630 0.02419916 0.00386938 0.00000234 0.47D-01 13733.64<br class=""> 7 5 12 0 -2888.65916047 -2888.65916548 -0.00000501 0.00570816 0.00087036 0.00000036 0.54D-02 16177.15<br class=""> WARNING: exit with wrong ci vector!!<br class=""> 8 7 12 786 -2888.50045888 -2888.50278318 -0.00232429 0.14825178 0.00435252 0.00000015 0.32D+00 18419.89<br class=""> 9 4 11 0 -2888.65281628 -2888.65851734 -0.00570106 0.12034652 0.00261341 0.00004805 0.27D+00 20491.25<br class=""> 10 4 11 0 -2888.65895243 -2888.65913562 -0.00018319 0.02411394 0.00373151 0.00000238 0.48D-01 22809.80<br class=""> 11 5 11 0 -2888.65916035 -2888.65916545 -0.00000510 0.00568229 0.00087519 0.00000063 0.56D-02 25128.05<br class=""> WARNING: exit with wrong ci vector!!<br class=""> 12 7 12 786 -2888.50047277 -2888.50278714 -0.00231437 0.14806859 0.00359637 0.00000015 0.32D+00 27332.06<br class=""> 13 4 11 0 -2888.65286565 -2888.65852136 -0.00565571 0.12016013 0.00262332 0.00004798 0.27D+00 29399.38<br class=""> 14 4 11 0 -2888.65895467 -2888.65913585 -0.00018118 0.02406651 0.00373916 0.00000237 0.48D-01 31700.03<br class=""> 15 5 12 0 -2888.65916039 -2888.65916546 -0.00000506 0.00567262 0.00088874 0.00000037 0.55D-02 34138.52<br class=""> WARNING: exit with wrong ci vector!!<br class=""> 16 7 12 786 -2888.50048819 -2888.50279081 -0.00230262 0.14783537 0.00352199 0.00000015 0.32D+00 36344.33<br class=""> 17 4 11 0 -2888.65291533 -2888.65852541 -0.00561008 0.11995809 0.00263353 0.00004788 0.27D+00 38402.12<br class=""> 18 4 11 0 -2888.65895692 -2888.65913608 -0.00017916 0.02401553 0.00374651 0.00000237 0.48D-01 40697.63<br class=""> 19 5 12 0 -2888.65916044 -2888.65916547 -0.00000503 0.00566261 0.00090308 0.00000037 0.55D-02 43139.95<br class=""> WARNING: exit with wrong ci vector!!<br class=""> 20 7 12 786 -2888.50050353 -2888.50279445 -0.00229092 0.14760125 0.00345623 0.00000015 0.32D+00 45376.72<br class=""> 21 4 11 0 -2888.65296457 -2888.65852943 -0.00556486 0.11975525 0.00264392 0.00004779 0.27D+00 47439.36<br class=""> 22 4 11 0 -2888.65895914 -2888.65913631 -0.00017717 0.02396491 0.00375398 0.00000237 0.47D-01 49754.06</div></div><div class=""><br class=""></div><div class="">As you can see, every 4 iterations there is a message "WARNING: exit with wrong ci vector!!” and there is jump (the energy change and the gradients suddenly increase by two orders of magnitude). Although the iteration procedure continues, the convergence is extremely slow… and the calculations are not going to converge in a reasonable number of iterations.</div><div class=""><br class=""></div><div class="">Following the manual, I have already tried the following options:</div><div class="">#1. switch off the coupling between CI coefficients and orbital rotations and disable the simultaneous optimisation of internal orbitals & CI, i.e.: "{iterations;do,uncouple,1,to,40;}" and "{iterations;dont,internal,1,to,40;}"</div><div class="">Without these options it’s even worse: the jump occurs in every single iteration!</div><div class="">#2. temporarily replace CLOSED with FROZEN</div><div class="">#3. change the orbital optimisation method from WERNER to AUGMENT</div><div class="">However, none of these really helped to avoid the oscillations (except for #1, without which the problem was even more severe). </div><div class=""><br class=""></div><div class="">Is there anything more I can try to converge these CASSCF calculations more smoothly? </div><div class="">Thank you in advance for your suggestions!</div><div class=""><div class=""><br class=""></div><div class="">Best regards,</div><div class="">Mariusz Radon</div></div><div class=""><br class=""></div>P.S. Perhaps I should add that the active space is chosen consciously and I know these calculations are doable (because I was able to converge them in another program, Molcas; however, I need to perform them also in Molpro because Molcas doesn’t have the NEVPT2 method). Moreover, my initial guess is also fairly reasonably (the natural orbitals for the lowest one of these 10 states, computed with exactly the same active space; so I don’t see how can I improve it further). Also the number of states included (10) is well justified because it accounts for quasi-degeneracy of the excited electronic states in this (qualitatively) octahedral complex. The real symmetry is however much lower, only Ci. The basis set is a mix of cc-pVTZ-DK (on the metal and nearest neighbours) and cc-pVDZ-DK (on the less important atoms).<div class=""></div><br class=""><div class="">
<div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; 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word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="color: rgb(0, 0, 0); letter-spacing: normal; orphans: auto; text-align: start; text-indent: 0px; text-transform: none; white-space: normal; widows: auto; word-spacing: 0px; -webkit-text-stroke-width: 0px; word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div class="">-- <br class="">Mariusz Radon, Ph.D.<br class="">Faculty of Chemistry</div><div class="">Jagiellonian University</div><div class="">ul. Ingardena 3</div><div class="">30-060 Krakow, Poland<br class=""><br class="">phone: 48-12-663-22-31</div><div class=""><div class="">e-mail: <a href="mailto:mradon@chemia.uj.edu.pl" class="">mradon@chemia.uj.edu.pl</a> </div><div class="">or <a href="mailto:mradon@chemia.uj.edu.pl" class="">mariusz.radon@uj.edu.pl</a></div><div class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class=""><div style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" class="">web: <a href="http://www.chemia.uj.edu.pl/~mradon" class="">http://www.chemia.uj.edu.pl/~mradon</a></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div></div>
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