[molpro-user] unreasonable norm in UCCSD(T)
Tatiana Korona
tania at tiger.chem.uw.edu.pl
Thu Jun 9 13:58:19 CEST 2016
Hi,
In CC theory the Ansatz for the wave function PsiCC is not normalized to unity,
but rather we impose an intermediate normalization, i.e. <Phi0|PsiCC>=1, where
Phi0 is the reference Hartree-Fock determinant, i.e.
PsiCC=exp(^T)Phi0=Phi0+ ^C Phi0, C - excitation operator from Phi0.
^C=\sum_tau c_tau ^tau
In standard situations all amplitudes c_tau are small in comparison to one.
However, if in your exact wave function some determinants other than Phi0 play
an important role, the intermediate normalization wrt to Phi0 requires that
these determinants have huge c_tau amplitudes (much larger than 1).
Summarizing - UCCSD(T) results are nonsense, as you have noticed, and you can
either find a better reference determinant, e.g. by analysing your UCCSD(T)
output, or switch to some multireference program (CASSCF, MRCI etc.).
Best wishes,
Tatiana
On Tue, 7 Jun 2016, Marissa Weichman wrote:
> Hello all,
>
> 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.
>
> 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.
>
> 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 here
> <https://www.molpro.net/info/2015.1/doc/manual/node177.html>) and couldn't
> change this behavior.
>
> 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?
>
> Thank you!
>
> Marissa
>
> --
>
> Example input:
>
> ***,Fe4O_13_uccsdt_avdz
> memory,3000,mw
>
> geomtyp=xyz
> geometry={
> 5 ! number of atoms
>
> optimized Fe4O 13-tet c2v with TPSS/6-311+g*
> O 0.0000 0.0000 2.0572
> Fe 0.0000 1.2201 0.7011
> Fe 0.0000 -1.2201 0.7011
> Fe -1.1884 0.0000 -0.9952
> Fe 1.1884 0.0000 -0.9952
> }
>
> set,charge=0
> set,spin=12 ! spin=2s, so this is the 13-tet
>
> basis={default=avdz}
>
> set,cc_norm_max=100.0
> hf,maxit=200;shift,-1.0,-0.5
> uccsd(t),maxit=200
>
>
> --
>
> Relevant part of the output:
>
> Starting UCCSD calculation
>
> ITER. SQ.NORM CORR.ENERGY TOTAL ENERGY ENERGY CHANGE
> DEN1 VAR(S) VAR(P) DIIS TIME
> 1 1.52677747 -1.24852238 -5125.26012928 -1.24852238
> -0.22253355 0.13D+00 0.62D-01 0 0 79.24
> 2 1.81205924 -1.45502934 -5125.46663624 -0.20650696
> -0.08456664 0.35D-01 0.37D-01 1 1 122.30
> 3 1.87264052 -1.40483018 -5125.41643708 0.05019916
> -0.01720839 0.16D-01 0.38D-02 2 2 163.42
> 4 2.07225408 -1.42258668 -5125.43419359 -0.01775650
> -0.01100110 0.97D-02 0.27D-02 3 3 202.18
> 5 2.51432027 -1.45370712 -5125.46531403 -0.03112044
> -0.00773249 0.78D-02 0.16D-02 4 4 240.94
> 6 2.95585742 -1.47016080 -5125.48176770 -0.01645367
> -0.00631234 0.62D-02 0.14D-02 5 5 279.89
> 7 3.43510225 -1.48164422 -5125.49325113 -0.01148343
> -0.00521287 0.48D-02 0.12D-02 6 6 319.00
> 8 4.18490168 -1.49443359 -5125.50604049 -0.01278936
> -0.00441521 0.41D-02 0.97D-03 6 4 358.15
> 9 4.86484426 -1.50303940 -5125.51464630 -0.00860581
> -0.00393151 0.36D-02 0.84D-03 6 1 401.27
> 10 5.79617501 -1.51247370 -5125.52408060 -0.00943430
> -0.00347500 0.32D-02 0.68D-03 6 4 446.76
> 11 6.73168654 -1.51863335 -5125.53024025 -0.00615965
> -0.00317530 0.29D-02 0.60D-03 6 5 491.01
> 12 7.88625768 -1.52758897 -5125.53919588 -0.00895563
> -0.00282700 0.26D-02 0.53D-03 6 2 530.81
> 13 8.95620834 -1.53041514 -5125.54202205 -0.00282617
> -0.00251092 0.23D-02 0.42D-03 6 3 571.93
> 14 10.33352126 -1.53597414 -5125.54758104 -0.00555899
> -0.00219265 0.20D-02 0.41D-03 6 6 611.25
> 15 11.13695846 -1.53778236 -5125.54938927 -0.00180822
> -0.00190764 0.17D-02 0.35D-03 6 1 650.78
> 16 12.73368576 -1.54166175 -5125.55326865 -0.00387938
> -0.00154031 0.13D-02 0.33D-03 6 2 690.20
> 17 14.45438474 -1.54585419 -5125.55746109 -0.00419244
> -0.00122090 0.99D-03 0.29D-03 6 4 729.68
> 18 14.89809783 -1.54671418 -5125.55832108 -0.00085998
> -0.00112134 0.86D-03 0.30D-03 6 6 769.08
> 19 15.50867378 -1.54829204 -5125.55989895 -0.00157787
> -0.00082978 0.59D-03 0.25D-03 6 2 811.53
> 20 17.87941931 -1.55230457 -5125.56391147 -0.00401253
> -0.00047247 0.32D-03 0.15D-03 6 5 855.72
> 21 17.68841351 -1.55176171 -5125.56336861 0.00054286
> -0.00042453 0.27D-03 0.15D-03 6 2 896.12
> 22 17.65413588 -1.55194576 -5125.56355266 -0.00018405
> -0.00032914 0.20D-03 0.12D-03 6 1 937.49
> 23 18.17319799 -1.55253493 -5125.56414183 -0.00058917
> -0.00021239 0.15D-03 0.70D-04 6 3 980.50
> 24 18.33739898 -1.55272718 -5125.56433409 -0.00019226
> -0.00016958 0.12D-03 0.59D-04 6 4 1021.76
> 25 18.49514646 -1.55304748 -5125.56465439 -0.00032030
> -0.00014060 0.10D-03 0.46D-04 6 3 1063.06
> 26 19.02753787 -1.55384276 -5125.56544966 -0.00079527
> -0.00010626 0.78D-04 0.34D-04 6 6 1102.74
> 27 19.29226045 -1.55410366 -5125.56571056 -0.00026090
> -0.00008659 0.61D-04 0.30D-04 6 2 1142.27
> 28 19.69307693 -1.55471830 -5125.56632520 -0.00061464
> -0.00006294 0.46D-04 0.21D-04 6 5 1181.74
> 29 19.91148754 -1.55473878 -5125.56634568 -0.00002049
> -0.00005084 0.37D-04 0.17D-04 6 3 1221.21
> 30 20.21334043 -1.55511008 -5125.56671699 -0.00037130
> -0.00004094 0.27D-04 0.15D-04 6 6 1260.68
> 31 20.56654112 -1.55524288 -5125.56684978 -0.00013280
> -0.00002973 0.20D-04 0.11D-04 6 4 1300.15
> 32 20.96647640 -1.55551919 -5125.56712609 -0.00027631
> -0.00002128 0.13D-04 0.86D-05 6 1 1339.62
> 33 21.31372706 -1.55571914 -5125.56732604 -0.00019994
> -0.00001535 0.85D-05 0.66D-05 6 3 1378.74
> 34 21.59806637 -1.55579609 -5125.56740299 -0.00007696
> -0.00001160 0.61D-05 0.51D-05 6 6 1423.79
> 35 21.85187169 -1.55601396 -5125.56762086 -0.00021787
> -0.00000799 0.44D-05 0.33D-05 6 5 1468.81
> 36 22.06696413 -1.55605417 -5125.56766107 -0.00004021
> -0.00000573 0.36D-05 0.21D-05 6 2 1513.78
> 37 22.16220603 -1.55611503 -5125.56772193 -0.00006086
> -0.00000459 0.30D-05 0.16D-05 6 3 1554.29
> 38 22.27870356 -1.55611929 -5125.56772619 -0.00000426
> -0.00000336 0.24D-05 0.10D-05 6 5 1593.42
> 39 22.32591879 -1.55615097 -5125.56775787 -0.00003168
> -0.00000273 0.21D-05 0.75D-06 6 3 1637.26
> 40 22.39863057 -1.55616423 -5125.56777113 -0.00001326
> -0.00000228 0.17D-05 0.63D-06 6 2 1682.24
> 41 22.47648448 -1.55620346 -5125.56781037 -0.00003924
> -0.00000191 0.14D-05 0.55D-06 6 4 1726.86
> 42 22.58214664 -1.55625981 -5125.56786671 -0.00005635
> -0.00000158 0.11D-05 0.51D-06 6 6 1767.27
> 43 22.69790660 -1.55631690 -5125.56792381 -0.00005709
> -0.00000121 0.79D-06 0.39D-06 6 1 1809.98
> 44 22.73099295 -1.55634345 -5125.56795035 -0.00002654
> -0.00000104 0.64D-06 0.36D-06 6 6 1855.64
> 45 22.77366705 -1.55640959 -5125.56801650 -0.00006615
> -0.00000067 0.44D-06 0.23D-06 6 2 1899.84
> 46 22.79457772 -1.55642812 -5125.56803502 -0.00001853
> -0.00000057 0.37D-06 0.20D-06 6 6 1944.80
> 47 22.79999700 -1.55644503 -5125.56805193 -0.00001691
> -0.00000051 0.32D-06 0.18D-06 6 2 1989.61
> 48 22.81333024 -1.55645875 -5125.56806566 -0.00001373
> -0.00000043 0.27D-06 0.16D-06 6 6 2029.01
> 49 22.81751109 -1.55648633 -5125.56809323 -0.00002758
> -0.00000030 0.16D-06 0.13D-06 6 1 2068.36
> 50 22.81697710 -1.55649854 -5125.56810544 -0.00001221
> -0.00000023 0.13D-06 0.97D-07 6 5 2109.24
> 51 22.83327975 -1.55649937 -5125.56810627 -0.00000083
> -0.00000015 0.81D-07 0.68D-07 6 3 2150.05
> 52 22.85082754 -1.55651415 -5125.56812105 -0.00001478
> -0.00000012 0.60D-07 0.53D-07 6 4 2192.50
> 53 22.87017137 -1.55652036 -5125.56812726 -0.00000621
> -0.00000008 0.48D-07 0.34D-07 6 5 2231.65
> 54 22.87734936 -1.55652583 -5125.56813273 -0.00000547
> -0.00000007 0.40D-07 0.28D-07 6 4 2270.86
> 55 22.88451494 -1.55652322 -5125.56813013 0.00000261
> -0.00000004 0.28D-07 0.17D-07 6 6 2310.10
> 56 22.88141922 -1.55652418 -5125.56813108 -0.00000096
> -0.00000003 0.24D-07 0.99D-08 6 2 2355.19
> 57 22.88292739 -1.55652095 -5125.56812785 0.00000324
> -0.00000003 0.20D-07 0.83D-08 6 3 2394.37
> 58 22.88398875 -1.55652179 -5125.56812869 -0.00000084
> -0.00000002 0.18D-07 0.65D-08 6 5 2433.51
> 59 22.89459290 -1.55652373 -5125.56813063 -0.00000194
> -0.00000002 0.12D-07 0.50D-08 6 1 2472.72
> 60 22.90307444 -1.55652446 -5125.56813136 -0.00000073
> -0.00000001 0.83D-08 0.44D-08 6 6 2511.84
> 61 22.91111322 -1.55652661 -5125.56813352 -0.00000215
> -0.00000001 0.60D-08 0.35D-08 6 4 2550.93
>
> Norm of t1 vector: 2.47041773 S-energy: -0.12884505 T1
> diagnostic: 0.26231356
> D1
> diagnostic: 0.87368671
> Norm of t2 vector: 3.97594636 P-energy: -1.42768156
> Alpha-Beta: -0.92084599
> Alpha-Alpha: -0.33717095
> Beta-Beta: -0.16966463
>
> --
> Marissa L. Weichman
> Neumark Group
> Department of Chemistry
> University of California, Berkeley
>
Dr. Tatiana Korona http://tiger.chem.uw.edu.pl/staff/tania/index.html
Quantum Chemistry Laboratory, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, POLAND
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