<div dir="ltr"><div>Hello all,</div><div><br></div><div>I am trying to run single-point energy calculations for small iron monoxide clusters in MOLPRO 2010.1. I am using UCCSD(T)/AVDZ at cluster geometries previously optimized with DFT. Being ferromagnetic, these clusters have incredibly high electronic spin, which I believe is causing some problems.</div><div><br></div><div>For a few of the spin states I'm interested in, my UCCSD(T) calculation converges very nicely. In a few cases, however, the RHF and RMP2 calculations converge without issue, but the UCCSD(T) part only gets a few iterations before the value of SQ. NORM starts increasing, and MOLPRO throws the "UNREASONABLE NORM. CALCULATION STOPPED" error and crashes.</div><div><br></div><div>I have read that this error is often caused by a strange or incorrect electron configuration. However, I have thoroughly checked the electron orbital occupations in the prior RHF and RMP2 steps against my sensible DFT calculations, and everything is consistent. I also played around extensively with different level shift parameters and convergence algorithms (as recommended <a href="https://www.molpro.net/info/2015.1/doc/manual/node177.html">here</a>) and couldn't change this behavior.</div><div><br></div><div>If I use "set,cc_norm_max=100.0" (as I show in the example input below), and ignore the fact that SQ. NORM gets to a value of 20+, the UCCSD(T) calculation does converge (as also shown below). But I do get a final energy that is fishy compared to my other calculations that converged normally. Are there any other tricks I should be trying?</div><div><br></div><div>Thank you!</div><div><br></div><div>Marissa</div><div><br></div><div>--</div><div><br></div><div>Example input:</div><div><br></div><div>***,Fe4O_13_uccsdt_avdz</div><div>memory,3000,mw</div><div><br></div><div>geomtyp=xyz</div><div>geometry={</div><div>5 ! number of atoms</div><div><br></div><div>optimized Fe4O 13-tet c2v with TPSS/6-311+g*</div><div>O<span class="" style="white-space:pre"> </span>0.0000<span class="" style="white-space:pre"> </span>0.0000<span class="" style="white-space:pre"> </span>2.0572<span class="" style="white-space:pre"> </span> </div><div>Fe<span class="" style="white-space:pre"> </span>0.0000<span class="" style="white-space:pre"> </span>1.2201<span class="" style="white-space:pre"> </span>0.7011<span class="" style="white-space:pre"> </span> </div><div>Fe<span class="" style="white-space:pre"> </span>0.0000<span class="" style="white-space:pre"> </span>-1.2201<span class="" style="white-space:pre"> </span>0.7011<span class="" style="white-space:pre"> </span> </div><div>Fe<span class="" style="white-space:pre"> </span>-1.1884<span class="" style="white-space:pre"> </span>0.0000<span class="" style="white-space:pre"> </span>-0.9952<span class="" style="white-space:pre"> </span> </div><div>Fe<span class="" style="white-space:pre"> </span>1.1884<span class="" style="white-space:pre"> </span>0.0000<span class="" style="white-space:pre"> </span>-0.9952<span class="" style="white-space:pre"> </span></div><div>} </div><div><br></div><div>set,charge=0</div><div>set,spin=12 ! spin=2s, so this is the 13-tet</div><div><br></div><div>basis={default=avdz}</div><div><br></div><div>set,cc_norm_max=100.0</div><div>hf,maxit=200;shift,-1.0,-0.5</div><div>uccsd(t),maxit=200</div><div><br></div><div><br></div><div>--</div><div><br></div><div>Relevant part of the output:</div><div><br></div><div> Starting UCCSD calculation</div><div><br></div><div> ITER. SQ.NORM CORR.ENERGY TOTAL ENERGY ENERGY CHANGE DEN1 VAR(S) VAR(P) DIIS TIME</div><div> 1 1.52677747 -1.24852238 -5125.26012928 -1.24852238 -0.22253355 0.13D+00 0.62D-01 0 0 79.24</div><div> 2 1.81205924 -1.45502934 -5125.46663624 -0.20650696 -0.08456664 0.35D-01 0.37D-01 1 1 122.30</div><div> 3 1.87264052 -1.40483018 -5125.41643708 0.05019916 -0.01720839 0.16D-01 0.38D-02 2 2 163.42</div><div> 4 2.07225408 -1.42258668 -5125.43419359 -0.01775650 -0.01100110 0.97D-02 0.27D-02 3 3 202.18</div><div> 5 2.51432027 -1.45370712 -5125.46531403 -0.03112044 -0.00773249 0.78D-02 0.16D-02 4 4 240.94</div><div> 6 2.95585742 -1.47016080 -5125.48176770 -0.01645367 -0.00631234 0.62D-02 0.14D-02 5 5 279.89</div><div> 7 3.43510225 -1.48164422 -5125.49325113 -0.01148343 -0.00521287 0.48D-02 0.12D-02 6 6 319.00</div><div> 8 4.18490168 -1.49443359 -5125.50604049 -0.01278936 -0.00441521 0.41D-02 0.97D-03 6 4 358.15</div><div> 9 4.86484426 -1.50303940 -5125.51464630 -0.00860581 -0.00393151 0.36D-02 0.84D-03 6 1 401.27</div><div> 10 5.79617501 -1.51247370 -5125.52408060 -0.00943430 -0.00347500 0.32D-02 0.68D-03 6 4 446.76</div><div> 11 6.73168654 -1.51863335 -5125.53024025 -0.00615965 -0.00317530 0.29D-02 0.60D-03 6 5 491.01</div><div> 12 7.88625768 -1.52758897 -5125.53919588 -0.00895563 -0.00282700 0.26D-02 0.53D-03 6 2 530.81</div><div> 13 8.95620834 -1.53041514 -5125.54202205 -0.00282617 -0.00251092 0.23D-02 0.42D-03 6 3 571.93</div><div> 14 10.33352126 -1.53597414 -5125.54758104 -0.00555899 -0.00219265 0.20D-02 0.41D-03 6 6 611.25</div><div> 15 11.13695846 -1.53778236 -5125.54938927 -0.00180822 -0.00190764 0.17D-02 0.35D-03 6 1 650.78</div><div> 16 12.73368576 -1.54166175 -5125.55326865 -0.00387938 -0.00154031 0.13D-02 0.33D-03 6 2 690.20</div><div> 17 14.45438474 -1.54585419 -5125.55746109 -0.00419244 -0.00122090 0.99D-03 0.29D-03 6 4 729.68</div><div> 18 14.89809783 -1.54671418 -5125.55832108 -0.00085998 -0.00112134 0.86D-03 0.30D-03 6 6 769.08</div><div> 19 15.50867378 -1.54829204 -5125.55989895 -0.00157787 -0.00082978 0.59D-03 0.25D-03 6 2 811.53</div><div> 20 17.87941931 -1.55230457 -5125.56391147 -0.00401253 -0.00047247 0.32D-03 0.15D-03 6 5 855.72</div><div> 21 17.68841351 -1.55176171 -5125.56336861 0.00054286 -0.00042453 0.27D-03 0.15D-03 6 2 896.12</div><div> 22 17.65413588 -1.55194576 -5125.56355266 -0.00018405 -0.00032914 0.20D-03 0.12D-03 6 1 937.49</div><div> 23 18.17319799 -1.55253493 -5125.56414183 -0.00058917 -0.00021239 0.15D-03 0.70D-04 6 3 980.50</div><div> 24 18.33739898 -1.55272718 -5125.56433409 -0.00019226 -0.00016958 0.12D-03 0.59D-04 6 4 1021.76</div><div> 25 18.49514646 -1.55304748 -5125.56465439 -0.00032030 -0.00014060 0.10D-03 0.46D-04 6 3 1063.06</div><div> 26 19.02753787 -1.55384276 -5125.56544966 -0.00079527 -0.00010626 0.78D-04 0.34D-04 6 6 1102.74</div><div> 27 19.29226045 -1.55410366 -5125.56571056 -0.00026090 -0.00008659 0.61D-04 0.30D-04 6 2 1142.27</div><div> 28 19.69307693 -1.55471830 -5125.56632520 -0.00061464 -0.00006294 0.46D-04 0.21D-04 6 5 1181.74</div><div> 29 19.91148754 -1.55473878 -5125.56634568 -0.00002049 -0.00005084 0.37D-04 0.17D-04 6 3 1221.21</div><div> 30 20.21334043 -1.55511008 -5125.56671699 -0.00037130 -0.00004094 0.27D-04 0.15D-04 6 6 1260.68</div><div> 31 20.56654112 -1.55524288 -5125.56684978 -0.00013280 -0.00002973 0.20D-04 0.11D-04 6 4 1300.15</div><div> 32 20.96647640 -1.55551919 -5125.56712609 -0.00027631 -0.00002128 0.13D-04 0.86D-05 6 1 1339.62</div><div> 33 21.31372706 -1.55571914 -5125.56732604 -0.00019994 -0.00001535 0.85D-05 0.66D-05 6 3 1378.74</div><div> 34 21.59806637 -1.55579609 -5125.56740299 -0.00007696 -0.00001160 0.61D-05 0.51D-05 6 6 1423.79</div><div> 35 21.85187169 -1.55601396 -5125.56762086 -0.00021787 -0.00000799 0.44D-05 0.33D-05 6 5 1468.81</div><div> 36 22.06696413 -1.55605417 -5125.56766107 -0.00004021 -0.00000573 0.36D-05 0.21D-05 6 2 1513.78</div><div> 37 22.16220603 -1.55611503 -5125.56772193 -0.00006086 -0.00000459 0.30D-05 0.16D-05 6 3 1554.29</div><div> 38 22.27870356 -1.55611929 -5125.56772619 -0.00000426 -0.00000336 0.24D-05 0.10D-05 6 5 1593.42</div><div> 39 22.32591879 -1.55615097 -5125.56775787 -0.00003168 -0.00000273 0.21D-05 0.75D-06 6 3 1637.26</div><div> 40 22.39863057 -1.55616423 -5125.56777113 -0.00001326 -0.00000228 0.17D-05 0.63D-06 6 2 1682.24</div><div> 41 22.47648448 -1.55620346 -5125.56781037 -0.00003924 -0.00000191 0.14D-05 0.55D-06 6 4 1726.86</div><div> 42 22.58214664 -1.55625981 -5125.56786671 -0.00005635 -0.00000158 0.11D-05 0.51D-06 6 6 1767.27</div><div> 43 22.69790660 -1.55631690 -5125.56792381 -0.00005709 -0.00000121 0.79D-06 0.39D-06 6 1 1809.98</div><div> 44 22.73099295 -1.55634345 -5125.56795035 -0.00002654 -0.00000104 0.64D-06 0.36D-06 6 6 1855.64</div><div> 45 22.77366705 -1.55640959 -5125.56801650 -0.00006615 -0.00000067 0.44D-06 0.23D-06 6 2 1899.84</div><div> 46 22.79457772 -1.55642812 -5125.56803502 -0.00001853 -0.00000057 0.37D-06 0.20D-06 6 6 1944.80</div><div> 47 22.79999700 -1.55644503 -5125.56805193 -0.00001691 -0.00000051 0.32D-06 0.18D-06 6 2 1989.61</div><div> 48 22.81333024 -1.55645875 -5125.56806566 -0.00001373 -0.00000043 0.27D-06 0.16D-06 6 6 2029.01</div><div> 49 22.81751109 -1.55648633 -5125.56809323 -0.00002758 -0.00000030 0.16D-06 0.13D-06 6 1 2068.36</div><div> 50 22.81697710 -1.55649854 -5125.56810544 -0.00001221 -0.00000023 0.13D-06 0.97D-07 6 5 2109.24</div><div> 51 22.83327975 -1.55649937 -5125.56810627 -0.00000083 -0.00000015 0.81D-07 0.68D-07 6 3 2150.05</div><div> 52 22.85082754 -1.55651415 -5125.56812105 -0.00001478 -0.00000012 0.60D-07 0.53D-07 6 4 2192.50</div><div> 53 22.87017137 -1.55652036 -5125.56812726 -0.00000621 -0.00000008 0.48D-07 0.34D-07 6 5 2231.65</div><div> 54 22.87734936 -1.55652583 -5125.56813273 -0.00000547 -0.00000007 0.40D-07 0.28D-07 6 4 2270.86</div><div> 55 22.88451494 -1.55652322 -5125.56813013 0.00000261 -0.00000004 0.28D-07 0.17D-07 6 6 2310.10</div><div> 56 22.88141922 -1.55652418 -5125.56813108 -0.00000096 -0.00000003 0.24D-07 0.99D-08 6 2 2355.19</div><div> 57 22.88292739 -1.55652095 -5125.56812785 0.00000324 -0.00000003 0.20D-07 0.83D-08 6 3 2394.37</div><div> 58 22.88398875 -1.55652179 -5125.56812869 -0.00000084 -0.00000002 0.18D-07 0.65D-08 6 5 2433.51</div><div> 59 22.89459290 -1.55652373 -5125.56813063 -0.00000194 -0.00000002 0.12D-07 0.50D-08 6 1 2472.72</div><div> 60 22.90307444 -1.55652446 -5125.56813136 -0.00000073 -0.00000001 0.83D-08 0.44D-08 6 6 2511.84</div><div> 61 22.91111322 -1.55652661 -5125.56813352 -0.00000215 -0.00000001 0.60D-08 0.35D-08 6 4 2550.93</div><div><br></div><div> Norm of t1 vector: 2.47041773 S-energy: -0.12884505 T1 diagnostic: 0.26231356</div><div> D1 diagnostic: 0.87368671</div><div> Norm of t2 vector: 3.97594636 P-energy: -1.42768156</div><div> Alpha-Beta: -0.92084599</div><div> Alpha-Alpha: -0.33717095</div><div> Beta-Beta: -0.16966463</div><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><div dir="ltr"><span style="font-size:13px">Marissa L. Weichman</span><br><div style="font-size:13px">Neumark Group</div><div style="font-size:13px">Department of Chemistry</div><div style="font-size:13px">University of California, Berkeley</div></div></div>
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