Automatic UHF calculation for odd number of electrons #1107

gasevic · 2024-09-20T12:14:26Z

Describe the bug
If a system contains an odd number of electrons, xTB will automatically enforce a UHF calculation with one unpaired electron. However, this adjustment occurs without any warning, and the output incorrectly displays unpaired electrons = 0, which can be misleading. This becomes particularly problematic when the system is supposed to carry a charge, but the charge information is missing.

To Reproduce
Steps to reproduce the behaviour:

happens for systems with uneven electron count (e.g. H3O+, see input geometry)
run xtb struc.xyz vs. xtb struc.xyz -uhf 1 yields the same result

Input Geometry

4
energy: -5.088192529146 gnorm: 0.000115842525 xtb: 6.7.1 (edcfbbe)
O            0.12705489143145        0.12705489143175        0.12705489142261
H            1.05992566989601       -0.09349028052419       -0.09349028080321
H           -0.09349028052419        1.05992566988652       -0.09349028079401
H           -0.09349028080327       -0.09349028079407        1.05992567017460

Output without charge and UHF information

    -----------------------------------------------------------      
   |                   =====================                   |     
   |                           x T B                           |     
   |                   =====================                   |     
   |                         S. Grimme                         |     
   |          Mulliken Center for Theoretical Chemistry        |     
   |                    University of Bonn                     |     
    -----------------------------------------------------------      

 * xtb version 6.7.1 (edcfbbe) compiled by 'albert@albert-system' on 2024-07-22

 xtb is free software: you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 xtb is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Lesser General Public License for more details.
 
 Cite this work as:
 * C. Bannwarth, E. Caldeweyher, S. Ehlert, A. Hansen, P. Pracht,
   J. Seibert, S. Spicher, S. Grimme, WIREs Comput. Mol. Sci., 2020, 11,
   e01493. DOI: 10.1002/wcms.1493
 
 for GFN2-xTB:
 * C. Bannwarth, S. Ehlert and S. Grimme., J. Chem. Theory Comput., 2019,
   15, 1652-1671. DOI: 10.1021/acs.jctc.8b01176
 for GFN1-xTB:
 * S. Grimme, C. Bannwarth, P. Shushkov, J. Chem. Theory Comput., 2017,
   13, 1989-2009. DOI: 10.1021/acs.jctc.7b00118
 for GFN0-xTB:
 * P. Pracht, E. Caldeweyher, S. Ehlert, S. Grimme, ChemRxiv, 2019, preprint.
   DOI: 10.26434/chemrxiv.8326202.v1
 for GFN-FF:
 * S. Spicher and S. Grimme, Angew. Chem. Int. Ed., 2020, 59, 15665-15673.
   DOI: 10.1002/anie.202004239
 
 for ALPB and GBSA implicit solvation:
 * S. Ehlert, M. Stahn, S. Spicher, S. Grimme, J. Chem. Theory Comput.,
   2021, 17, 4250-4261. DOI: 10.1021/acs.jctc.1c00471
 
 for ddCOSMO and CPCM-X implicit solvation:
 * M. Stahn, S. Ehlert, S. Grimme, J. Phys. Chem. A,
   2023, XX, XXXX-XXXX. DOI: 10.1021/acs.jpca.3c04382
 
 for DFT-D4:
 * E. Caldeweyher, C. Bannwarth and S. Grimme, J. Chem. Phys., 2017,
   147, 034112. DOI: 10.1063/1.4993215
 * E. Caldeweyher, S. Ehlert, A. Hansen, H. Neugebauer, S. Spicher,
   C. Bannwarth and S. Grimme, J. Chem. Phys., 2019, 150, 154122.
   DOI: 10.1063/1.5090222
 * E. Caldeweyher, J.-M. Mewes, S. Ehlert and S. Grimme, Phys. Chem. Chem. Phys.
   2020, 22, 8499-8512. DOI: 10.1039/D0CP00502A
 
 for sTDA-xTB:
 * S. Grimme and C. Bannwarth, J. Chem. Phys., 2016, 145, 054103.
   DOI: 10.1063/1.4959605
 
 in the mass-spec context:
 * V. Asgeirsson, C. Bauer and S. Grimme, Chem. Sci., 2017, 8, 4879.
   DOI: 10.1039/c7sc00601b
 * J. Koopman and S. Grimme, ACS Omega 2019, 4, 12, 15120-15133.
   DOI: 10.1021/acsomega.9b02011
 
 for metadynamics refer to:
 * S. Grimme, J. Chem. Theory Comput., 2019, 155, 2847-2862
   DOI: 10.1021/acs.jctc.9b00143
 
 for SPH calculations refer to:
 * S. Spicher and S. Grimme, J. Chem. Theory Comput., 2021, 17, 1701-1714
   DOI: 10.1021/acs.jctc.0c01306
 
 for ONIOM refer to:
 * C. Plett, A. Katbashev, S. Ehlert, S. Grimme, M. Bursch,
   Phys. Chem. Chem. Phys., 2023, 25, 17860-17868. DOI: 10.1039/D3CP02178E
 
 for DIPRO refer to:
 * J. Kohn, N. Gildemeister, S. Grimme, D. Fazzi, A. Hansen,
   J. Chem. Phys., 2023, just accepted.
 
 for PTB refer to:
 * S. Grimme, M. Mueller, A. Hansen, J. Chem. Phys., 2023, 158, 124111.
   DOI: 10.1063/5.0137838
 
 with help from (in alphabetical order)
 P. Atkinson, C. Bannwarth, F. Bohle, G. Brandenburg, E. Caldeweyher
 M. Checinski, S. Dohm, S. Ehlert, S. Ehrlich, I. Gerasimov, C. Hölzer
 A. Katbashev, J. Kohn, J. Koopman, C. Lavigne, S. Lehtola, F. März, M. Müller,
 F. Musil, H. Neugebauer, J. Pisarek, C. Plett, P. Pracht, F. Pultar,
 J. Seibert, P. Shushkov, S. Spicher, M. Stahn, M. Steiner, T. Strunk,
 J. Stückrath, T. Rose, and J. Unsleber
 
* started run on 2024/09/20 at 14:00:03.258     
 ID    Z sym.   atoms
  1    8 O      1
  2    1 H      2-4

         -------------------------------------------------
        |                Calculation Setup                |
         -------------------------------------------------

        program call               : xtb struc.xyz
        hostname                   : fs7
        coordinate file            : struc.xyz
        omp threads                :                    16


         -------------------------------------------------
        |                 G F N 2 - x T B                 |
         -------------------------------------------------

      Reference                      10.1021/acs.jctc.8b01176
    * Hamiltonian:
      H0-scaling (s, p, d)           1.850000    2.230000    2.230000
      zeta-weighting                 0.500000
    * Dispersion:
      s8                             2.700000
      a1                             0.520000
      a2                             5.000000
      s9                             5.000000
    * Repulsion:
      kExp                           1.500000    1.000000
      rExp                           1.000000
    * Coulomb:
      alpha                          2.000000
      third order                    shell-resolved
      anisotropic                    true
      a3                             3.000000
      a5                             4.000000
      cn-shift                       1.200000
      cn-exp                         4.000000
      max-rad                        5.000000


        ...................................................
        :                      SETUP                      :
        :.................................................:
        :  # basis functions                   7          :
        :  # atomic orbitals                   7          :
        :  # shells                            5          :
        :  # electrons                         9          :
        :  max. iterations                   250          :
        :  Hamiltonian                  GFN2-xTB          :
        :  restarted?                      false          :
        :  GBSA solvation                  false          :
        :  PC potential                    false          :
        :  electronic temp.          300.0000000     K    :
        :  accuracy                    1.0000000          :
        :  -> integral cutoff          0.2500000E+02      :
        :  -> integral neglect         0.1000000E-07      :
        :  -> SCF convergence          0.1000000E-05 Eh   :
        :  -> wf. convergence          0.1000000E-03 e    :
        :  Broyden damping             0.4000000          :
        :  net charge                          0          :
        :  unpaired electrons                  0          :
        ...................................................

iter      E             dE          RMSdq      gap      omega  full diag
 1     -5.3100896 -0.531009E+01  0.370E+00    7.10       0.0  T
 2     -5.3139697 -0.388014E-02  0.205E+00    7.03       1.0  T
 3     -5.3143846 -0.414920E-03  0.484E-01    6.97       1.0  T
 4     -5.3144274 -0.427168E-04  0.194E-02    6.98       2.6  T
 5     -5.3144277 -0.382685E-06  0.288E-03    6.99      17.3  T
 6     -5.3144277 -0.366471E-08  0.700E-04    6.99      71.5  T
 7     -5.3144277 -0.270234E-09  0.225E-06    6.99   22232.1  T

 *** convergence criteria satisfied after 7 iterations ***

       #    Occupation            Energy/Eh            Energy/eV
    -------------------------------------------------------------
       1        2.0000           -0.7141239             -19.4323
       2        2.0000           -0.5902729             -16.0621
       3        2.0000           -0.5902729             -16.0621
       4        2.0000           -0.5096717             -13.8689
       5        1.0000           -0.0354997              -0.9660 (HOMO)
       6                          0.2212163               6.0196 (LUMO)
       7                          0.2212163               6.0196
    -------------------------------------------------------------
                HL-Gap            0.2567159 Eh            6.9856 eV
           Fermi-level           -0.0898637 Eh           -2.4453 eV

SCC (total)                   0 d,  0 h,  0 min,  0.025 sec
SCC setup                      ...        0 min,  0.000 sec (  0.825%)
Dispersion                     ...        0 min,  0.000 sec (  0.224%)
classical contributions        ...        0 min,  0.000 sec (  0.093%)
integral evaluation            ...        0 min,  0.000 sec (  1.462%)
iterations                     ...        0 min,  0.023 sec ( 93.684%)
molecular gradient             ...        0 min,  0.000 sec (  1.275%)
printout                       ...        0 min,  0.001 sec (  2.205%)

       :::::::::::::::::::::::::::::::::::::::::::::::::::::
       ::                     SUMMARY                     ::
       :::::::::::::::::::::::::::::::::::::::::::::::::::::
       :: total energy              -5.272973255368 Eh    ::
       :: gradient norm              0.401699536387 Eh/a0 ::
       :: HOMO-LUMO gap              6.985596493021 eV    ::
       ::.................................................::
       :: SCC energy                -5.314427737259 Eh    ::
       :: -> isotropic ES            0.014765319486 Eh    ::
       :: -> anisotropic ES         -0.002096930954 Eh    ::
       :: -> anisotropic XC         -0.000223642105 Eh    ::
       :: -> dispersion             -0.000321892002 Eh    ::
       :: repulsion energy           0.041454481891 Eh    ::
       :: add. restraining           0.000000000000 Eh    ::
       :: total charge              -0.000000000000 e     ::
       :::::::::::::::::::::::::::::::::::::::::::::::::::::

         -------------------------------------------------
        |                Property Printout                |
         -------------------------------------------------

  * Orbital Energies and Occupations

       #    Occupation            Energy/Eh            Energy/eV
    -------------------------------------------------------------
       1        2.0000           -0.7141239             -19.4323
       2        2.0000           -0.5902729             -16.0621
       3        2.0000           -0.5902729             -16.0621
       4        2.0000           -0.5096717             -13.8689
       5        1.0000           -0.0354997              -0.9660 (HOMO)
       6                          0.2212163               6.0196 (LUMO)
       7                          0.2212163               6.0196
    -------------------------------------------------------------
                HL-Gap            0.2567159 Eh            6.9856 eV
           Fermi-level           -0.0898637 Eh           -2.4453 eV

   #   Z          covCN         q      C6AA      α(0)
   1   8 O        2.407    -0.428    21.345     6.240
   2   1 H        0.802     0.143     1.469     1.904
   3   1 H        0.802     0.143     1.469     1.904
   4   1 H        0.802     0.143     1.469     1.904

Mol. C6AA /au·bohr⁶  :         67.533629
Mol. C8AA /au·bohr⁸  :       1105.504428
Mol. α(0) /au        :         11.951096


Wiberg/Mayer (AO) data.
largest (>0.10) Wiberg bond orders for each atom

---------------------------------------------------------------------------
   #   Z sym  total        # sym  WBO       # sym  WBO       # sym  WBO
---------------------------------------------------------------------------
   1   8 O    2.150 --     3 H    0.717     2 H    0.717     4 H    0.717
   2   1 H    0.920 --     1 O    0.717     4 H    0.102     3 H    0.102
   3   1 H    0.920 --     1 O    0.717     4 H    0.102     2 H    0.102
   4   1 H    0.920 --     1 O    0.717     2 H    0.102     3 H    0.102
---------------------------------------------------------------------------

Topologies differ in total number of bonds
Writing topology from bond orders to xtbtopo.mol

molecular dipole:
               x           y           z       tot (Debye)
q only:        0.133       0.133       0.133
 full:        0.178       0.178       0.178       0.784
molecular quadrupole (traceless):
              xx          xy          yy          xz          yz          zz
q only:        0.000      -0.182       0.000      -0.182      -0.182      -0.000
q+dip:        0.000      -0.123       0.000      -0.123      -0.123      -0.000
 full:        0.000      -0.284       0.000      -0.284      -0.284      -0.000


         -------------------------------------------------
        | TOTAL ENERGY               -5.272973255368 Eh   |
        | GRADIENT NORM               0.401699536387 Eh/α |
        | HOMO-LUMO GAP               6.985596493021 eV   |
         -------------------------------------------------

------------------------------------------------------------------------
* finished run on 2024/09/20 at 14:00:03.301     
------------------------------------------------------------------------
total:
* wall-time:     0 d,  0 h,  0 min,  0.042 sec
*  cpu-time:     0 d,  0 h,  0 min,  0.578 sec
* ratio c/w:    13.870 speedup
SCF:
* wall-time:     0 d,  0 h,  0 min,  0.025 sec
*  cpu-time:     0 d,  0 h,  0 min,  0.382 sec
* ratio c/w:    15.043 speedup

Output with given UHF information

    -----------------------------------------------------------      
   |                   =====================                   |     
   |                           x T B                           |     
   |                   =====================                   |     
   |                         S. Grimme                         |     
   |          Mulliken Center for Theoretical Chemistry        |     
   |                    University of Bonn                     |     
    -----------------------------------------------------------      

 * xtb version 6.7.1 (edcfbbe) compiled by 'albert@albert-system' on 2024-07-22

 xtb is free software: you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 xtb is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Lesser General Public License for more details.
 
 Cite this work as:
 * C. Bannwarth, E. Caldeweyher, S. Ehlert, A. Hansen, P. Pracht,
   J. Seibert, S. Spicher, S. Grimme, WIREs Comput. Mol. Sci., 2020, 11,
   e01493. DOI: 10.1002/wcms.1493
 
 for GFN2-xTB:
 * C. Bannwarth, S. Ehlert and S. Grimme., J. Chem. Theory Comput., 2019,
   15, 1652-1671. DOI: 10.1021/acs.jctc.8b01176
 for GFN1-xTB:
 * S. Grimme, C. Bannwarth, P. Shushkov, J. Chem. Theory Comput., 2017,
   13, 1989-2009. DOI: 10.1021/acs.jctc.7b00118
 for GFN0-xTB:
 * P. Pracht, E. Caldeweyher, S. Ehlert, S. Grimme, ChemRxiv, 2019, preprint.
   DOI: 10.26434/chemrxiv.8326202.v1
 for GFN-FF:
 * S. Spicher and S. Grimme, Angew. Chem. Int. Ed., 2020, 59, 15665-15673.
   DOI: 10.1002/anie.202004239
 
 for ALPB and GBSA implicit solvation:
 * S. Ehlert, M. Stahn, S. Spicher, S. Grimme, J. Chem. Theory Comput.,
   2021, 17, 4250-4261. DOI: 10.1021/acs.jctc.1c00471
 
 for ddCOSMO and CPCM-X implicit solvation:
 * M. Stahn, S. Ehlert, S. Grimme, J. Phys. Chem. A,
   2023, XX, XXXX-XXXX. DOI: 10.1021/acs.jpca.3c04382
 
 for DFT-D4:
 * E. Caldeweyher, C. Bannwarth and S. Grimme, J. Chem. Phys., 2017,
   147, 034112. DOI: 10.1063/1.4993215
 * E. Caldeweyher, S. Ehlert, A. Hansen, H. Neugebauer, S. Spicher,
   C. Bannwarth and S. Grimme, J. Chem. Phys., 2019, 150, 154122.
   DOI: 10.1063/1.5090222
 * E. Caldeweyher, J.-M. Mewes, S. Ehlert and S. Grimme, Phys. Chem. Chem. Phys.
   2020, 22, 8499-8512. DOI: 10.1039/D0CP00502A
 
 for sTDA-xTB:
 * S. Grimme and C. Bannwarth, J. Chem. Phys., 2016, 145, 054103.
   DOI: 10.1063/1.4959605
 
 in the mass-spec context:
 * V. Asgeirsson, C. Bauer and S. Grimme, Chem. Sci., 2017, 8, 4879.
   DOI: 10.1039/c7sc00601b
 * J. Koopman and S. Grimme, ACS Omega 2019, 4, 12, 15120-15133.
   DOI: 10.1021/acsomega.9b02011
 
 for metadynamics refer to:
 * S. Grimme, J. Chem. Theory Comput., 2019, 155, 2847-2862
   DOI: 10.1021/acs.jctc.9b00143
 
 for SPH calculations refer to:
 * S. Spicher and S. Grimme, J. Chem. Theory Comput., 2021, 17, 1701-1714
   DOI: 10.1021/acs.jctc.0c01306
 
 for ONIOM refer to:
 * C. Plett, A. Katbashev, S. Ehlert, S. Grimme, M. Bursch,
   Phys. Chem. Chem. Phys., 2023, 25, 17860-17868. DOI: 10.1039/D3CP02178E
 
 for DIPRO refer to:
 * J. Kohn, N. Gildemeister, S. Grimme, D. Fazzi, A. Hansen,
   J. Chem. Phys., 2023, just accepted.
 
 for PTB refer to:
 * S. Grimme, M. Mueller, A. Hansen, J. Chem. Phys., 2023, 158, 124111.
   DOI: 10.1063/5.0137838
 
 with help from (in alphabetical order)
 P. Atkinson, C. Bannwarth, F. Bohle, G. Brandenburg, E. Caldeweyher
 M. Checinski, S. Dohm, S. Ehlert, S. Ehrlich, I. Gerasimov, C. Hölzer
 A. Katbashev, J. Kohn, J. Koopman, C. Lavigne, S. Lehtola, F. März, M. Müller,
 F. Musil, H. Neugebauer, J. Pisarek, C. Plett, P. Pracht, F. Pultar,
 J. Seibert, P. Shushkov, S. Spicher, M. Stahn, M. Steiner, T. Strunk,
 J. Stückrath, T. Rose, and J. Unsleber
 
* started run on 2024/09/20 at 14:00:17.801     
 ID    Z sym.   atoms
  1    8 O      1
  2    1 H      2-4

         -------------------------------------------------
        |                Calculation Setup                |
         -------------------------------------------------

        program call               : xtb struc.xyz --uhf 1
        hostname                   : fs7
        coordinate file            : struc.xyz
        omp threads                :                    16


         -------------------------------------------------
        |                 G F N 2 - x T B                 |
         -------------------------------------------------

      Reference                      10.1021/acs.jctc.8b01176
    * Hamiltonian:
      H0-scaling (s, p, d)           1.850000    2.230000    2.230000
      zeta-weighting                 0.500000
    * Dispersion:
      s8                             2.700000
      a1                             0.520000
      a2                             5.000000
      s9                             5.000000
    * Repulsion:
      kExp                           1.500000    1.000000
      rExp                           1.000000
    * Coulomb:
      alpha                          2.000000
      third order                    shell-resolved
      anisotropic                    true
      a3                             3.000000
      a5                             4.000000
      cn-shift                       1.200000
      cn-exp                         4.000000
      max-rad                        5.000000


        ...................................................
        :                      SETUP                      :
        :.................................................:
        :  # basis functions                   7          :
        :  # atomic orbitals                   7          :
        :  # shells                            5          :
        :  # electrons                         9          :
        :  max. iterations                   250          :
        :  Hamiltonian                  GFN2-xTB          :
        :  restarted?                      false          :
        :  GBSA solvation                  false          :
        :  PC potential                    false          :
        :  electronic temp.          300.0000000     K    :
        :  accuracy                    1.0000000          :
        :  -> integral cutoff          0.2500000E+02      :
        :  -> integral neglect         0.1000000E-07      :
        :  -> SCF convergence          0.1000000E-05 Eh   :
        :  -> wf. convergence          0.1000000E-03 e    :
        :  Broyden damping             0.4000000          :
        :  net charge                          0          :
        :  unpaired electrons                  1          :
        ...................................................

iter      E             dE          RMSdq      gap      omega  full diag
 1     -5.3100896 -0.531009E+01  0.370E+00    7.10       0.0  T
 2     -5.3139697 -0.388014E-02  0.205E+00    7.03       1.0  T
 3     -5.3143846 -0.414920E-03  0.484E-01    6.97       1.0  T
 4     -5.3144274 -0.427168E-04  0.194E-02    6.98       2.6  T
 5     -5.3144277 -0.382685E-06  0.288E-03    6.99      17.3  T
 6     -5.3144277 -0.366471E-08  0.700E-04    6.99      71.5  T
 7     -5.3144277 -0.270234E-09  0.225E-06    6.99   22232.1  T

 *** convergence criteria satisfied after 7 iterations ***

       #    Occupation            Energy/Eh            Energy/eV
    -------------------------------------------------------------
       1        2.0000           -0.7141239             -19.4323
       2        2.0000           -0.5902729             -16.0621
       3        2.0000           -0.5902729             -16.0621
       4        2.0000           -0.5096717             -13.8689
       5        1.0000           -0.0354997              -0.9660 (HOMO)
       6                          0.2212163               6.0196 (LUMO)
       7                          0.2212163               6.0196
    -------------------------------------------------------------
                HL-Gap            0.2567159 Eh            6.9856 eV
           Fermi-level           -0.0898637 Eh           -2.4453 eV

SCC (total)                   0 d,  0 h,  0 min,  0.025 sec
SCC setup                      ...        0 min,  0.000 sec (  1.855%)
Dispersion                     ...        0 min,  0.000 sec (  1.729%)
classical contributions        ...        0 min,  0.000 sec (  0.455%)
integral evaluation            ...        0 min,  0.000 sec (  1.701%)
iterations                     ...        0 min,  0.023 sec ( 91.178%)
molecular gradient             ...        0 min,  0.000 sec (  1.322%)
printout                       ...        0 min,  0.000 sec (  1.511%)

       :::::::::::::::::::::::::::::::::::::::::::::::::::::
       ::                     SUMMARY                     ::
       :::::::::::::::::::::::::::::::::::::::::::::::::::::
       :: total energy              -5.272973255368 Eh    ::
       :: gradient norm              0.401699536387 Eh/a0 ::
       :: HOMO-LUMO gap              6.985596493021 eV    ::
       ::.................................................::
       :: SCC energy                -5.314427737259 Eh    ::
       :: -> isotropic ES            0.014765319486 Eh    ::
       :: -> anisotropic ES         -0.002096930954 Eh    ::
       :: -> anisotropic XC         -0.000223642105 Eh    ::
       :: -> dispersion             -0.000321892002 Eh    ::
       :: repulsion energy           0.041454481891 Eh    ::
       :: add. restraining           0.000000000000 Eh    ::
       :: total charge              -0.000000000000 e     ::
       :::::::::::::::::::::::::::::::::::::::::::::::::::::

         -------------------------------------------------
        |                Property Printout                |
         -------------------------------------------------

  * Orbital Energies and Occupations

       #    Occupation            Energy/Eh            Energy/eV
    -------------------------------------------------------------
       1        2.0000           -0.7141239             -19.4323
       2        2.0000           -0.5902729             -16.0621
       3        2.0000           -0.5902729             -16.0621
       4        2.0000           -0.5096717             -13.8689
       5        1.0000           -0.0354997              -0.9660 (HOMO)
       6                          0.2212163               6.0196 (LUMO)
       7                          0.2212163               6.0196
    -------------------------------------------------------------
                HL-Gap            0.2567159 Eh            6.9856 eV
           Fermi-level           -0.0898637 Eh           -2.4453 eV

   #   Z          covCN         q      C6AA      α(0)
   1   8 O        2.407    -0.428    21.345     6.240
   2   1 H        0.802     0.143     1.469     1.904
   3   1 H        0.802     0.143     1.469     1.904
   4   1 H        0.802     0.143     1.469     1.904

Mol. C6AA /au·bohr⁶  :         67.533629
Mol. C8AA /au·bohr⁸  :       1105.504428
Mol. α(0) /au        :         11.951096


Wiberg/Mayer (AO) data.
largest (>0.10) Wiberg bond orders for each atom

---------------------------------------------------------------------------
   #   Z sym  total        # sym  WBO       # sym  WBO       # sym  WBO
---------------------------------------------------------------------------
   1   8 O    2.150 --     3 H    0.717     2 H    0.717     4 H    0.717
   2   1 H    0.920 --     1 O    0.717     4 H    0.102     3 H    0.102
   3   1 H    0.920 --     1 O    0.717     4 H    0.102     2 H    0.102
   4   1 H    0.920 --     1 O    0.717     2 H    0.102     3 H    0.102
---------------------------------------------------------------------------

Topologies differ in total number of bonds
Writing topology from bond orders to xtbtopo.mol

molecular dipole:
               x           y           z       tot (Debye)
q only:        0.133       0.133       0.133
 full:        0.178       0.178       0.178       0.784
molecular quadrupole (traceless):
              xx          xy          yy          xz          yz          zz
q only:        0.000      -0.182       0.000      -0.182      -0.182      -0.000
q+dip:        0.000      -0.123       0.000      -0.123      -0.123      -0.000
 full:        0.000      -0.284       0.000      -0.284      -0.284      -0.000


         -------------------------------------------------
        | TOTAL ENERGY               -5.272973255368 Eh   |
        | GRADIENT NORM               0.401699536387 Eh/α |
        | HOMO-LUMO GAP               6.985596493021 eV   |
         -------------------------------------------------

------------------------------------------------------------------------
* finished run on 2024/09/20 at 14:00:17.887     
------------------------------------------------------------------------
total:
* wall-time:     0 d,  0 h,  0 min,  0.085 sec
*  cpu-time:     0 d,  0 h,  0 min,  1.220 sec
* ratio c/w:    14.362 speedup
SCF:
* wall-time:     0 d,  0 h,  0 min,  0.026 sec
*  cpu-time:     0 d,  0 h,  0 min,  0.391 sec
* ratio c/w:    14.900 speedup

Output with given charge information

    -----------------------------------------------------------      
   |                   =====================                   |     
   |                           x T B                           |     
   |                   =====================                   |     
   |                         S. Grimme                         |     
   |          Mulliken Center for Theoretical Chemistry        |     
   |                    University of Bonn                     |     
    -----------------------------------------------------------      

 * xtb version 6.7.1 (edcfbbe) compiled by 'albert@albert-system' on 2024-07-22

 xtb is free software: you can redistribute it and/or modify it under
 the terms of the GNU Lesser General Public License as published by
 the Free Software Foundation, either version 3 of the License, or
 (at your option) any later version.
 
 xtb is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 GNU Lesser General Public License for more details.
 
 Cite this work as:
 * C. Bannwarth, E. Caldeweyher, S. Ehlert, A. Hansen, P. Pracht,
   J. Seibert, S. Spicher, S. Grimme, WIREs Comput. Mol. Sci., 2020, 11,
   e01493. DOI: 10.1002/wcms.1493
 
 for GFN2-xTB:
 * C. Bannwarth, S. Ehlert and S. Grimme., J. Chem. Theory Comput., 2019,
   15, 1652-1671. DOI: 10.1021/acs.jctc.8b01176
 for GFN1-xTB:
 * S. Grimme, C. Bannwarth, P. Shushkov, J. Chem. Theory Comput., 2017,
   13, 1989-2009. DOI: 10.1021/acs.jctc.7b00118
 for GFN0-xTB:
 * P. Pracht, E. Caldeweyher, S. Ehlert, S. Grimme, ChemRxiv, 2019, preprint.
   DOI: 10.26434/chemrxiv.8326202.v1
 for GFN-FF:
 * S. Spicher and S. Grimme, Angew. Chem. Int. Ed., 2020, 59, 15665-15673.
   DOI: 10.1002/anie.202004239
 
 for ALPB and GBSA implicit solvation:
 * S. Ehlert, M. Stahn, S. Spicher, S. Grimme, J. Chem. Theory Comput.,
   2021, 17, 4250-4261. DOI: 10.1021/acs.jctc.1c00471
 
 for ddCOSMO and CPCM-X implicit solvation:
 * M. Stahn, S. Ehlert, S. Grimme, J. Phys. Chem. A,
   2023, XX, XXXX-XXXX. DOI: 10.1021/acs.jpca.3c04382
 
 for DFT-D4:
 * E. Caldeweyher, C. Bannwarth and S. Grimme, J. Chem. Phys., 2017,
   147, 034112. DOI: 10.1063/1.4993215
 * E. Caldeweyher, S. Ehlert, A. Hansen, H. Neugebauer, S. Spicher,
   C. Bannwarth and S. Grimme, J. Chem. Phys., 2019, 150, 154122.
   DOI: 10.1063/1.5090222
 * E. Caldeweyher, J.-M. Mewes, S. Ehlert and S. Grimme, Phys. Chem. Chem. Phys.
   2020, 22, 8499-8512. DOI: 10.1039/D0CP00502A
 
 for sTDA-xTB:
 * S. Grimme and C. Bannwarth, J. Chem. Phys., 2016, 145, 054103.
   DOI: 10.1063/1.4959605
 
 in the mass-spec context:
 * V. Asgeirsson, C. Bauer and S. Grimme, Chem. Sci., 2017, 8, 4879.
   DOI: 10.1039/c7sc00601b
 * J. Koopman and S. Grimme, ACS Omega 2019, 4, 12, 15120-15133.
   DOI: 10.1021/acsomega.9b02011
 
 for metadynamics refer to:
 * S. Grimme, J. Chem. Theory Comput., 2019, 155, 2847-2862
   DOI: 10.1021/acs.jctc.9b00143
 
 for SPH calculations refer to:
 * S. Spicher and S. Grimme, J. Chem. Theory Comput., 2021, 17, 1701-1714
   DOI: 10.1021/acs.jctc.0c01306
 
 for ONIOM refer to:
 * C. Plett, A. Katbashev, S. Ehlert, S. Grimme, M. Bursch,
   Phys. Chem. Chem. Phys., 2023, 25, 17860-17868. DOI: 10.1039/D3CP02178E
 
 for DIPRO refer to:
 * J. Kohn, N. Gildemeister, S. Grimme, D. Fazzi, A. Hansen,
   J. Chem. Phys., 2023, just accepted.
 
 for PTB refer to:
 * S. Grimme, M. Mueller, A. Hansen, J. Chem. Phys., 2023, 158, 124111.
   DOI: 10.1063/5.0137838
 
 with help from (in alphabetical order)
 P. Atkinson, C. Bannwarth, F. Bohle, G. Brandenburg, E. Caldeweyher
 M. Checinski, S. Dohm, S. Ehlert, S. Ehrlich, I. Gerasimov, C. Hölzer
 A. Katbashev, J. Kohn, J. Koopman, C. Lavigne, S. Lehtola, F. März, M. Müller,
 F. Musil, H. Neugebauer, J. Pisarek, C. Plett, P. Pracht, F. Pultar,
 J. Seibert, P. Shushkov, S. Spicher, M. Stahn, M. Steiner, T. Strunk,
 J. Stückrath, T. Rose, and J. Unsleber
 
* started run on 2024/09/20 at 14:05:38.957     
 ID    Z sym.   atoms
  1    8 O      1
  2    1 H      2-4

         -------------------------------------------------
        |                Calculation Setup                |
         -------------------------------------------------

        program call               : xtb struc.xyz --chrg 1
        hostname                   : fs7
        coordinate file            : struc.xyz
        omp threads                :                    16


         -------------------------------------------------
        |                 G F N 2 - x T B                 |
         -------------------------------------------------

      Reference                      10.1021/acs.jctc.8b01176
    * Hamiltonian:
      H0-scaling (s, p, d)           1.850000    2.230000    2.230000
      zeta-weighting                 0.500000
    * Dispersion:
      s8                             2.700000
      a1                             0.520000
      a2                             5.000000
      s9                             5.000000
    * Repulsion:
      kExp                           1.500000    1.000000
      rExp                           1.000000
    * Coulomb:
      alpha                          2.000000
      third order                    shell-resolved
      anisotropic                    true
      a3                             3.000000
      a5                             4.000000
      cn-shift                       1.200000
      cn-exp                         4.000000
      max-rad                        5.000000


        ...................................................
        :                      SETUP                      :
        :.................................................:
        :  # basis functions                   7          :
        :  # atomic orbitals                   7          :
        :  # shells                            5          :
        :  # electrons                         8          :
        :  max. iterations                   250          :
        :  Hamiltonian                  GFN2-xTB          :
        :  restarted?                      false          :
        :  GBSA solvation                  false          :
        :  PC potential                    false          :
        :  electronic temp.          300.0000000     K    :
        :  accuracy                    1.0000000          :
        :  -> integral cutoff          0.2500000E+02      :
        :  -> integral neglect         0.1000000E-07      :
        :  -> SCF convergence          0.1000000E-05 Eh   :
        :  -> wf. convergence          0.1000000E-03 e    :
        :  Broyden damping             0.4000000          :
        :  net charge                          1          :
        :  unpaired electrons                  0          :
        ...................................................

iter      E             dE          RMSdq      gap      omega  full diag
 1     -5.1294864 -0.512949E+01  0.378E+00   13.78       0.0  T
 2     -5.1296062 -0.119726E-03  0.221E+00   13.81       1.0  T
 3     -5.1296411 -0.349585E-04  0.108E-01   13.80       1.0  T
 4     -5.1296460 -0.490727E-05  0.500E-02   13.82       1.0  T
 5     -5.1296469 -0.864700E-06  0.126E-02   13.84       4.0  T
 6     -5.1296470 -0.124465E-06  0.107E-03   13.84      46.8  T
 7     -5.1296470 -0.540671E-09  0.657E-04   13.84      76.1  T
 8     -5.1296470 -0.320446E-09  0.115E-07   13.84  100000.0  T

 *** convergence criteria satisfied after 8 iterations ***

       #    Occupation            Energy/Eh            Energy/eV
    -------------------------------------------------------------
       1        2.0000           -1.0373177             -28.2269
       2        2.0000           -0.9196723             -25.0256
       3        2.0000           -0.9196723             -25.0256
       4        2.0000           -0.8447081             -22.9857 (HOMO)
       5                         -0.3361102              -9.1460 (LUMO)
       6                         -0.0811680              -2.2087
       7                         -0.0811680              -2.2087
    -------------------------------------------------------------
                HL-Gap            0.5085979 Eh           13.8397 eV
           Fermi-level           -0.5904091 Eh          -16.0659 eV

SCC (total)                   0 d,  0 h,  0 min,  0.022 sec
SCC setup                      ...        0 min,  0.001 sec (  2.562%)
Dispersion                     ...        0 min,  0.000 sec (  0.264%)
classical contributions        ...        0 min,  0.000 sec (  0.108%)
integral evaluation            ...        0 min,  0.000 sec (  0.855%)
iterations                     ...        0 min,  0.021 sec ( 93.156%)
molecular gradient             ...        0 min,  0.001 sec (  2.266%)
printout                       ...        0 min,  0.000 sec (  0.551%)

       :::::::::::::::::::::::::::::::::::::::::::::::::::::
       ::                     SUMMARY                     ::
       :::::::::::::::::::::::::::::::::::::::::::::::::::::
       :: total energy              -5.088192529146 Eh    ::
       :: gradient norm              0.000115842468 Eh/a0 ::
       :: HOMO-LUMO gap             13.839654468085 eV    ::
       ::.................................................::
       :: SCC energy                -5.129647011038 Eh    ::
       :: -> isotropic ES            0.148431073889 Eh    ::
       :: -> anisotropic ES         -0.007425341924 Eh    ::
       :: -> anisotropic XC          0.000904262657 Eh    ::
       :: -> dispersion             -0.000146840883 Eh    ::
       :: repulsion energy           0.041454481891 Eh    ::
       :: add. restraining           0.000000000000 Eh    ::
       :: total charge               1.000000000000 e     ::
       :::::::::::::::::::::::::::::::::::::::::::::::::::::

         -------------------------------------------------
        |                Property Printout                |
         -------------------------------------------------

  * Orbital Energies and Occupations

       #    Occupation            Energy/Eh            Energy/eV
    -------------------------------------------------------------
       1        2.0000           -1.0373177             -28.2269
       2        2.0000           -0.9196723             -25.0256
       3        2.0000           -0.9196723             -25.0256
       4        2.0000           -0.8447081             -22.9857 (HOMO)
       5                         -0.3361102              -9.1460 (LUMO)
       6                         -0.0811680              -2.2087
       7                         -0.0811680              -2.2087
    -------------------------------------------------------------
                HL-Gap            0.5085979 Eh           13.8397 eV
           Fermi-level           -0.5904091 Eh          -16.0659 eV

   #   Z          covCN         q      C6AA      α(0)
   1   8 O        2.407    -0.314    19.201     5.918
   2   1 H        0.802     0.438     0.421     1.019
   3   1 H        0.802     0.438     0.421     1.019
   4   1 H        0.802     0.438     0.421     1.019

Mol. C6AA /au·bohr⁶  :         39.727751
Mol. C8AA /au·bohr⁸  :        694.720396
Mol. α(0) /au        :          8.975319


Wiberg/Mayer (AO) data.
largest (>0.10) Wiberg bond orders for each atom

---------------------------------------------------------------------------
   #   Z sym  total        # sym  WBO       # sym  WBO       # sym  WBO
---------------------------------------------------------------------------
   1   8 O    2.424 --     3 H    0.808     2 H    0.808     4 H    0.808
   2   1 H    0.808 --     1 O    0.808
   3   1 H    0.808 --     1 O    0.808
   4   1 H    0.808 --     1 O    0.808
---------------------------------------------------------------------------

Topologies differ in total number of bonds
Writing topology from bond orders to xtbtopo.mol

molecular dipole:
               x           y           z       tot (Debye)
q only:        0.647       0.647       0.647
 full:        0.761       0.761       0.761       3.349
molecular quadrupole (traceless):
              xx          xy          yy          xz          yz          zz
q only:       -0.000      -0.472      -0.000      -0.472      -0.472       0.000
q+dip:       -0.000      -0.620      -0.000      -0.620      -0.620       0.000
 full:       -0.000      -0.650      -0.000      -0.650      -0.650       0.000


         -------------------------------------------------
        | TOTAL ENERGY               -5.088192529146 Eh   |
        | GRADIENT NORM               0.000115842468 Eh/α |
        | HOMO-LUMO GAP              13.839654468085 eV   |
         -------------------------------------------------

------------------------------------------------------------------------
* finished run on 2024/09/20 at 14:05:39.036     
------------------------------------------------------------------------
total:
* wall-time:     0 d,  0 h,  0 min,  0.078 sec
*  cpu-time:     0 d,  0 h,  0 min,  0.980 sec
* ratio c/w:    12.601 speedup
SCF:
* wall-time:     0 d,  0 h,  0 min,  0.023 sec
*  cpu-time:     0 d,  0 h,  0 min,  0.340 sec
* ratio c/w:    15.090 speedup

Expected behaviour
I would at least expect that the number of unpaired electrons is adjusted in the output and ideally a warning should be printed. In ORCA these calculations would immediately crash so that users do not obtain misleading results.

The text was updated successfully, but these errors were encountered:

marcelmbn · 2024-09-24T14:20:37Z

Just tested the example case and can confirm.

IMHO, there are two ways to proceed here:

In general (for both approaches): Fix the output for unpaired electrons so that it corresponds to what is actually happening during the calculation (here: 1).

Raise an error if either the assigned UHF number cannot agree with the total number of electrons (from geometry and net charge), and exit the calculation.
Just raise a big warning and proceed with the best assumption (if a UHF information is not given), and start the calculation (here with UHF=1). If UHF is explicitly given and it does not match to the total number of electrons, raise an error (and stop) anyway.

What's your take on this, @gasevic @cplett @Albkat?
Just mentioned some names to detect potential errors with typical applications if we change the procedure of such a fundamental functionality.

gasevic · 2024-09-24T14:42:49Z

It is probably more user-friendly to stop the calculation as a faulty input is given but I am fine with both approaches.

marcelmbn · 2024-09-26T10:53:02Z

After discussing this issue again with @cplett, we have decided to correct the unpaired electrons printout, and additionally raise and print a big warning to alert the user of a (possibly unintentional) changed calculation setup.
Justification:

we don't want to introduce breaking changes
there might be users who use this behavior as a “feature”

awvwgk · 2024-09-26T12:53:58Z

In the tblite we decided to stop a calculation in case we discover a mismatch regarding unpaired electrons and total number of electrons:

https://github.com/tblite/tblite/blob/36ff0cd9064138fe5e59e45190710522865a4c3a/src/tblite/xtb/singlepoint.f90#L145-L150

gasevic added the unconfirmed This report has not yet been confirmed by the developers label Sep 20, 2024

marcelmbn added bug Something isn't working easy to fix This issue has a low difficulty and little entry-barrier, great to get started with this project and removed unconfirmed This report has not yet been confirmed by the developers labels Sep 24, 2024

marcelmbn assigned marcelmbn and gasevic Sep 24, 2024

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Automatic UHF calculation for odd number of electrons #1107

Automatic UHF calculation for odd number of electrons #1107

gasevic commented Sep 20, 2024

marcelmbn commented Sep 24, 2024

gasevic commented Sep 24, 2024

marcelmbn commented Sep 26, 2024

awvwgk commented Sep 26, 2024

Automatic UHF calculation for odd number of electrons #1107

Automatic UHF calculation for odd number of electrons #1107

Comments

gasevic commented Sep 20, 2024

marcelmbn commented Sep 24, 2024

IMHO, there are two ways to proceed here:

gasevic commented Sep 24, 2024

marcelmbn commented Sep 26, 2024

awvwgk commented Sep 26, 2024