SCF failed to converge in RAS-2SF

Andres_Hernandez · February 14, 2024, 5:00pm

Hello,

I have encountered a problem during RAS-2SF calculations, output shows that during SCF convergence,

The system was previously optimized at the DFT level using PBE0/6-31G(d).

I have tried changing to thresh (6,12), modifying the SCF algorithm (diis_gdm, RCA_DIIS, GDM, diis_dm) and also MAX_SCF_CYCLES up to 5000 but nothing seems to work.

Here is the input $rem along with the $molecule

$molecule
0 1
O       16.527983000     -1.978757000      0.318795000
O      -12.603636000      3.105903000      0.532446000
C       14.114685000      0.932131000      0.825684000
C       -9.780713000      1.448873000      2.482772000
C       15.435037000      0.142470000      0.811678000
C      -11.200955000      1.716850000      1.965889000
C       15.287643000     -1.275872000      0.295797000
C      -11.268853000      2.864383000      0.979893000
C       13.315258000      0.671509000     -0.459466000
C       -8.762724000      1.481751000      1.330304000
C       14.817339000     -1.229065000     -1.141296000
C      -10.437903000      2.518555000     -0.235569000
C       13.645397000     -0.303438000     -1.336729000
C       -9.084657000      1.941769000      0.094994000
C       14.480639000      2.413953000      0.996596000
C       13.262737000      0.516896000      2.038015000
C       -9.386570000      2.498285000      3.535931000
C       -9.810206000      0.069848000      3.164441000
C       12.058901000      1.432726000     -0.681668000
C       -7.432180000      0.968109000      1.676470000
C       12.881704000     -0.558562000     -2.605415000
C       -8.174254000      1.892784000     -1.099824000
C       11.921375000      2.765035000     -0.841568000
C       -6.231731000      1.487504000      1.326035000
C       10.660564000      3.482131000     -1.046962000
C       -4.945441000      0.938834000      1.718611000
C       10.789602000      4.777205000     -1.799148000
C       -4.931896000     -0.289694000      2.582526000
C        9.481446000      2.993742000     -0.570679000
C       -3.811620000      1.567994000      1.284423000
C        8.170540000      3.555761000     -0.740860000
C       -2.454834000      1.182453000      1.540279000
C        7.052667000      2.969482000     -0.229915000
C       -1.377642000      1.868467000      1.065213000
C        5.697232000      3.444656000     -0.370438000
C        0.003395000      1.507643000      1.271896000
C        5.454950000      4.719795000     -1.126424000
C        0.307885000      0.285974000      2.092324000
C        4.696937000      2.691577000      0.187648000
C        0.971548000      2.296368000      0.704022000
C        3.289173000      2.932896000      0.155145000
C        2.385366000      2.096877000      0.747492000
H       16.163423000      0.655591000      0.167415000
H       15.853730000      0.136415000      1.827781000
H      -11.862461000      1.908436000      2.822214000
H      -11.577999000      0.817794000      1.458938000
H       14.545713000     -1.822431000      0.896931000
H      -10.873727000      3.780746000      1.442360000
H       15.657592000     -0.908846000     -1.777513000
H       14.545860000     -2.236247000     -1.485632000
H      -11.001404000      1.793248000     -0.845137000
H      -10.307100000      3.403978000     -0.873186000
H       15.149035000      2.520764000      1.859995000
H       13.599920000      3.035304000      1.182026000
H       15.003550000      2.803140000      0.115150000
H       13.029520000     -0.552697000      2.027617000
H       13.795008000      0.744123000      2.970331000
H       12.314393000      1.067014000      2.049854000
H       -9.411659000      3.514453000      3.127162000
H       -8.371180000      2.313360000      3.905113000
H      -10.071874000      2.456166000      4.391772000
H      -10.659787000      0.027213000      3.856581000
H       -8.906188000     -0.128788000      3.749169000
H       -9.930782000     -0.733475000      2.427974000
H       11.154105000      0.825170000     -0.751937000
H       -7.424331000      0.100298000      2.332195000
H       12.376762000     -1.533829000     -2.566573000
H       12.134835000      0.210210000     -2.816994000
H       13.572993000     -0.602783000     -3.457927000
H       -8.750777000      1.605791000     -1.989311000
H       -7.347939000      1.188777000     -0.976197000
H       -7.743932000      2.880351000     -1.315993000
H       16.803997000     -2.034441000      1.245223000
H      -13.120120000      3.368862000      1.308255000
H       12.816342000      3.384335000     -0.886170000
H       -6.198118000      2.391923000      0.719254000
H       11.132263000      4.596939000     -2.826406000
H        9.857562000      5.343006000     -1.848103000
H       11.548086000      5.413878000     -1.326155000
H       -5.458234000     -0.102853000      3.527039000
H       -5.452862000     -1.117444000      2.086454000
H       -3.922874000     -0.626123000      2.823863000
H        9.519936000      2.073204000      0.013436000
H       -3.943206000      2.458679000      0.667532000
H        8.070015000      4.477944000     -1.308813000
H       -2.280033000      0.290112000      2.135665000
H        7.174937000      2.039198000      0.327443000
H       -1.557823000      2.762669000      0.466428000
H        6.017046000      5.548156000     -0.678250000
H        4.401401000      5.002915000     -1.147409000
H        5.800145000      4.628131000     -2.163733000
H       -0.102032000      0.389105000      3.104546000
H       -0.155861000     -0.603127000      1.648809000
H        1.377837000      0.095081000      2.184334000
H        5.002911000      1.785163000      0.712886000
H        0.631628000      3.168920000      0.143543000
H        2.912955000      3.810289000     -0.369138000
H        2.773194000      1.224109000      1.270424000
O       12.162512000     -3.246943000      2.003095000
O      -16.610581000      1.849885000     -1.938356000
C        8.574146000     -1.983321000      1.803929000
C      -14.917943000     -1.004123000     -0.070016000
C       10.049336000     -2.047945000      2.224734000
C      -16.051146000     -0.165442000     -0.683366000
C       10.795142000     -3.205898000      1.594673000
C      -15.544470000      1.059759000     -1.417848000
C        8.435151000     -2.167398000      0.283348000
C      -13.722776000     -1.112608000     -1.032716000
C       10.778983000     -3.056215000      0.089141000
C      -14.700611000      0.603849000     -2.585942000
C        9.427787000     -2.694912000     -0.478052000
C      -13.669420000     -0.425531000     -2.202479000
C        8.039579000     -0.608817000      2.234920000
C        7.767489000     -3.071580000      2.534633000
C      -14.460367000     -0.372998000      1.254764000
C      -15.497825000     -2.396295000      0.233349000
C        7.130318000     -1.765513000     -0.253131000
C      -12.646938000     -2.011833000     -0.593608000
C        9.312118000     -2.983779000     -1.948853000
C      -12.621882000     -0.611950000     -3.264965000
C        6.897560000     -1.101648000     -1.408753000
C      -11.321727000     -1.760129000     -0.712173000
C        5.599166000     -0.671166000     -1.921996000
C      -10.236594000     -2.625549000     -0.287996000
C        5.670113000      0.434947000     -2.938396000
C      -10.566425000     -3.932436000      0.371833000
C        4.432658000     -1.246714000     -1.508938000
C       -8.962151000     -2.197209000     -0.535604000
C        3.102163000     -0.852304000     -1.870168000
C       -7.721218000     -2.854557000     -0.245627000
C        1.986721000     -1.491876000     -1.418911000
C       -6.526936000     -2.305665000     -0.607225000
C        0.625687000     -1.111223000     -1.705700000
C       -5.212834000     -2.850552000     -0.376130000
C        0.389898000      0.088362000     -2.579564000
C       -5.085513000     -4.154969000      0.356844000
C       -0.386881000     -1.860295000     -1.160737000
C       -4.143213000     -2.130574000     -0.843379000
C       -1.790328000     -1.624299000     -1.274442000
C       -2.751353000     -2.428005000     -0.727907000
H       10.553650000     -1.118975000      1.924356000
H       10.108295000     -2.108235000      3.320480000
H      -16.750812000      0.123786000      0.112947000
H      -16.616559000     -0.773914000     -1.403752000
H       10.312040000     -4.155216000      1.867797000
H      -14.923401000      1.674079000     -0.748707000
H       11.501678000     -2.270028000     -0.185701000
H       11.144229000     -3.976600000     -0.384190000
H      -15.364469000      0.195665000     -3.365067000
H      -14.192856000      1.463038000     -3.046169000
H        8.216559000     -0.461476000      3.307434000
H        6.962905000     -0.510645000      2.059015000
H        8.548108000      0.197960000      1.693367000
H        8.131642000     -4.076184000      2.295803000
H        7.841491000     -2.928361000      3.619840000
H        6.705408000     -3.030722000      2.268735000
H      -14.089117000      0.647015000      1.109594000
H      -13.651953000     -0.958916000      1.707284000
H      -15.293891000     -0.339251000      1.967500000
H      -16.425618000     -2.286164000      0.807815000
H      -14.817156000     -3.011602000      0.830592000
H      -15.733793000     -2.937211000     -0.690480000
H        6.275982000     -1.961545000      0.395819000
H      -12.950346000     -2.924821000     -0.083788000
H        8.277642000     -3.000554000     -2.298734000
H        9.851799000     -2.234608000     -2.545039000
H        9.775623000     -3.951903000     -2.175868000
H      -13.099366000     -0.589083000     -4.253634000
H      -12.073654000     -1.551228000     -3.162999000
H      -11.889585000      0.207216000     -3.257487000
H       12.170224000     -3.354964000      2.965687000
H      -17.122934000      2.166400000     -1.180175000
H        7.754534000     -0.786132000     -2.003174000
H      -11.012629000     -0.816554000     -1.160618000
H        6.313464000      0.131767000     -3.774502000
H        4.697199000      0.711364000     -3.347785000
H        6.126061000      1.332736000     -2.502348000
H      -11.184861000     -3.771712000      1.263562000
H      -11.147733000     -4.572847000     -0.303274000
H       -9.675350000     -4.484788000      0.675821000
H        4.500507000     -2.094472000     -0.826624000
H       -8.862478000     -1.229948000     -1.031078000
H        2.982145000      0.012164000     -2.518224000
H       -7.736947000     -3.813428000      0.268088000
H        2.118076000     -2.358316000     -0.768679000
H       -6.554087000     -1.347182000     -1.128277000
H        0.844719000      0.983545000     -2.138869000
H       -0.669373000      0.292993000     -2.739785000
H        0.854531000     -0.054828000     -3.562818000
H       -5.520674000     -4.080732000      1.361142000
H       -5.632459000     -4.948626000     -0.166858000
H       -4.048088000     -4.477125000      0.462205000
H       -0.095517000     -2.725851000     -0.563524000
H       -4.375088000     -1.202806000     -1.368857000
H       -2.125765000     -0.744115000     -1.820821000
H       -2.438374000     -3.318091000     -0.183920000
$end

$rem
jobtype         sp
exchange        hf
correlation     rasci
basis           6-31g(d)
unrestricted    false
!plot
!SCF_CHANGE_FOR diis_gdm, RCA_DIIS, GDM, diis_dm
SCF_ALGORITHM diis_dm
gui 2
!memory
mem_total       32000
mem_static      4000
max_scf_cycles  200
thresh          5
!ras
ras_roots       10
ras_act         4
ras_elec        4
ras_occ         0
ras_spin_mult   1
ras_act_orb     [311,312,313,314]
ras_occ         310
ras_nfrag       2
ras_nfrag_atoms [98,98]
ras_frag_mo     1
ras_frag_sets   [310,2,2]
!Plot
molden_format   true
print_orbitals  10
$end

@@@

Have you found a similar problem? How did you solve it?

jherbert · February 15, 2024, 2:34am

With THRESH=5 you’ll be lucky to converge anything. For a large molecule with 6-31G*, I would use THRESH = 12, as documented here:

Andres_Hernandez · March 4, 2024, 5:16pm

Thank you for your helpful response, while I’ve used thresh=12 and has resolved the convergence problem.

There is still some errors in my output.

It does not show the ME, just singlets.

In this case should I continue to modify to a higher thresh or change the active space?

 RAS-CI total energy for state   1:  -3393.779062817926
  Excitation energy (eV) =  0.000000000000
  Multiplicity: Singlet
       A       B     Total
SE  0.0473  0.0473  0.0946
ME  0.0419  0.0420  0.0839
    0.0893  0.0893  0.1785

 RAS-CI total energy for state   2:  -3393.714468214154
  Excitation energy (eV) =  1.757708598059
  Multiplicity: Triplet
       A       B     Total
SE  0.0000  0.8942  0.8942
ME  0.0000  0.0000  0.0000
    0.0000  0.8942  0.8942

 RAS-CI total energy for state   3:  -3393.714018122954
  Excitation energy (eV) =  1.769956202745
  Multiplicity: Triplet
       A       B     Total
SE  0.8941  0.0000  0.8941
ME  0.0000  0.0000  0.0000
    0.8941  0.0000  0.8941

 RAS-CI total energy for state   4:  -3393.647182267743
  Excitation energy (eV) =  3.588652355398
  Multiplicity: Singlet
       A       B     Total
SE  0.0000  0.0000  0.0000
ME  0.0000  0.0000  0.0000
    0.0000  0.0000  0.0000

 RAS-CI total energy for state   5:  -3393.641294725238
  Excitation energy (eV) =  3.748860538103
  Multiplicity: Singlet
       A       B     Total
SE  0.3532  0.4316  0.7848
ME  0.0620  0.0751  0.1371
    0.4152  0.5067  0.9219

 RAS-CI total energy for state   6:  -3393.633389531432
  Excitation energy (eV) =  3.963971806078
  Multiplicity: Singlet
       A       B     Total
SE  0.2316  0.2594  0.4910
ME  0.1895  0.2131  0.4026
    0.4210  0.4725  0.8935

 RAS-CI total energy for state   7:  -3393.630411027772
  Excitation energy (eV) =  4.045021014323
  Multiplicity: Singlet
       A       B     Total
SE  0.4226  0.3448  0.7673
ME  0.0732  0.0603  0.1335
    0.4957  0.4051  0.9008

 RAS-CI total energy for state   8:  -3393.625119975347
  Excitation energy (eV) =  4.188997876112
  Multiplicity: Singlet
       A       B     Total
SE  0.0011  0.0008  0.0020
ME  0.0006  0.0008  0.0014
    0.0018  0.0016  0.0034

 RAS-CI total energy for state   9:  -3393.615935482148
  Excitation energy (eV) =  4.438920651742
  Multiplicity: Singlet
       A       B     Total
SE  0.0781  0.0666  0.1447
ME  0.0759  0.0650  0.1409
    0.1540  0.1316  0.2857

 RAS-CI total energy for state  10:  -3393.614599662973
  Excitation energy (eV) =  4.475270140888
  Multiplicity: Singlet
       A       B     Total
SE  0.1688  0.1526  0.3215
ME  0.1631  0.1502  0.3133
    0.3319  0.3029  0.6347

jherbert · March 4, 2024, 6:09pm

That’s unlikely to be a THRESH issue at this point, in my opinion, although I am not sure what the issue is. I suggest that you find a small system in the original literature on this method, and see if you are able to reproduce those results before moving into something unknown.