Frequency Analysis Grid Density Problem


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Dear NWChem developers and users,

We are currently investigating tin gadolinium clusters and have run into troubles regarding the frequency analysis.
The clusters were previousyl geometry optimized and converged properly, we are thus able to use the movecs files as input for the frequency analysis. However the calculations print the following in the output file:

  convergence    iter        energy       DeltaE   RMS-Dens  Diis-err    time
---------------- ----- ----------------- --------- --------- ---------  ------
d=70,ls=0.0,diis     1  -3766.7449285324 -1.09D+04  9.84D-06  1.60D-06   157.4
                                                     1.17D-05  2.25D-06
Grid integrated density:     343.999999006691
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis     2  -3766.7449284587  7.37D-08  6.89D-06  1.79D-06   300.8
                                                     8.15D-06  2.40D-06
Grid integrated density:     343.999999006660
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis     3  -3766.7449283781  8.06D-08  4.56D-07  2.39D-06   444.6
                                                     2.82D-06  3.16D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d=70,ls=0.0,diis     4  -3766.7449285428 -1.65D-07  2.14D-07  1.35D-06   587.5
                                                     2.43D-07  1.74D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis     5  -3766.7449285465 -3.72D-09  1.47D-07  1.34D-06   730.3
                                                     1.43D-07  1.73D-06
Grid integrated density:     343.999999006663
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis     6  -3766.7449285501 -3.66D-09  3.81D-08  1.33D-06   873.1
                                                     7.22D-08  1.73D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis     7  -3766.7449285505 -3.62D-10  2.00D-08  1.33D-06  1015.8
                                                     2.39D-08  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis     8  -3766.7449285506 -7.82D-11  4.14D-09  1.33D-06  1158.5
                                                     5.10D-09  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis     9  -3766.7449285506 -5.46D-12  1.56D-09  1.33D-06  1301.6
                                                     2.00D-09  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis    10  -3766.7449285506 -5.46D-12  8.20D-10  1.33D-06  1444.4
                                                     1.57D-09  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis    11  -3766.7449285506 -1.27D-11  1.23D-10  1.33D-06  1587.1
                                                     2.72D-10  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
  Singularity in Pulay matrix. Error and Fock matrices removed.
  Singularity in Pulay matrix. Error and Fock matrices removed.
d= 0,ls=0.0,diis    12  -3766.7449285506  2.55D-11  5.96D-09  1.33D-06  1729.8
                                                     1.02D-08  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
  Singularity in Pulay matrix. Error and Fock matrices removed.
  Singularity in Pulay matrix. Error and Fock matrices removed.
  Singularity in Pulay matrix. Error and Fock matrices removed.
  Singularity in Pulay matrix. Error and Fock matrices removed.
d= 0,ls=0.0,diis    13  -3766.7449285506 -3.09D-11  1.71D-09  1.33D-06  1872.6
                                                     1.79D-09  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
  Singularity in Pulay matrix. Error and Fock matrices removed.
d= 0,ls=0.0,diis    14  -3766.7449285506  3.82D-11  2.90D-09  1.33D-06  2015.3
                                                     3.13D-09  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis    15  -3766.7449285506 -1.82D-11  1.80D-09  1.33D-06  2158.0
                                                     2.81D-09  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis    16  -3766.7449285506 -2.36D-11  6.90D-10  1.33D-06  2300.8
                                                     6.52D-10  1.72D-06
Grid integrated density:     343.999999006664
Requested integration accuracy:   0.10E-13
d= 0,ls=0.0,diis    17  -3766.7449285506  3.82D-11  4.16D-10  1.33D-06  2443.6
                                                     5.13D-10  1.72D-06


From what I read on other posts, this does not seem to be an error per se. However since the calculations do not converge at any point, it is not possible for us to calculate the frequencies.

We tried using heigher grid values similar to the trouble with negative frequencies:

grid lebedev sn 250 16 gd 750 16



We also tried using hartree fock as initial guess. What is the reason for this output? Is there a way to fix this?

Thank you in advance!