Regarding Convergence in CDFT-CI

Questions
#1

Dear Developers
I am trying to perform the CDFT-CI for an example given in the manual (example 5.29) which is not converging. I am using Q-Chem 6.0.
Thanks

Input

$molecule
   -1 1
   C        -1.453000       -1.953000       -0.264000
   N        -0.278000       -1.402000       -0.440000
   N        -1.804000       -2.052000        1.091000
   C        -0.687000       -1.548000        1.806000
   O        -0.688000       -1.514000        3.031000
   C         0.291000       -1.140000        0.799000
   C         1.500000       -0.563000        1.254000
   H         1.585000       -0.660000        2.346000
   C         2.608000        0.030000        0.605000
   C         2.763000        0.182000       -0.865000
   H         1.926000       -0.073000       -1.543000
   C         3.733000        0.548000        1.313000
   H         3.682000        0.571000        2.326000
   C         3.821000        0.875000       -1.473000
   H         3.844000        1.102000       -2.575000
   C         4.938000        1.111000        0.700000
   H         5.734000        1.441000        1.308000
   C         5.037000        1.228000       -0.739000
   O         6.011000        1.818000       -1.261000
   C        -3.000000       -2.533000        1.832000
   H        -2.859000       -2.250000        2.892000
   H        -3.829000       -2.121000        1.354000
   C        -2.373000       -2.282000       -1.448000
   H        -1.790000       -3.026000       -2.045000
   H        -2.626000       -1.300000       -1.865000
   H        -3.054000       -3.631000        1.855000
   H        -3.308000       -2.854000       -1.357000
   C         7.648000       -5.429000        0.303000
   H         8.028000       -4.514000        0.845000
   H         7.274000       -5.098000       -0.671000
   C         6.499001       -5.986000        1.016000
   C         6.462999       -6.032001        2.390000
   H         7.284000       -5.579000        2.957000
   C         5.243000       -6.435000        3.018000
   H         5.190001       -6.315001        4.035000
   C         4.242001       -7.048000        2.189000
   O         3.095000       -7.615000        2.715000
   H         2.500999       -7.869000        1.979000
   C         5.454000       -6.469000        0.200000
   H         5.565001       -6.363000       -0.835000
   C         4.294001       -7.003000        0.803000
   H         3.469000       -7.324000        0.139000
   H         8.511000       -6.108000        0.245000
$end

$rem
   SYMMETRY         = off
   SYM_IGNORE       = true
   METHOD           = b3lyp
   BASIS            = cc-pvdz
   UNRESTRICTED     = true
   SCF_CONVERGENCE  =  8
   MAX_SCF_CYCLES   = 200
   CDFTCI           = true
   CDFTCI_PRINT     = 2
   CDFT_THRESH      = 7
$end

$cdft
   1.0
   1.0   1   27
   0.0
   1.0   1   27 S
--------------
   0.0
   1.0   1   27
  -1.0
   1.0   1   27 S
$end

Last part of the output


  188   -1070.6972419191      3.23E-11
CDFT not converged.
  189   -1070.6972419191      3.27E-11
CDFT not converged.
  190   -1070.6972419204      3.44E-11
CDFT not converged.
  191   -1070.6972419187      3.45E-11
CDFT not converged.
  192   -1070.6972419192      3.57E-11
CDFT not converged.
  193   -1070.6972419193      3.55E-11
CDFT not converged.
  194   -1070.6972419192      3.63E-11
CDFT not converged.
  195   -1070.6972419193      1.89E-11
CDFT not converged.
  196   -1070.6972419183      2.50E-11
CDFT not converged.
  197   -1070.6972419199      3.29E-11
CDFT not converged.
  198   -1070.6972419184      3.22E-11
CDFT not converged.
  199   -1070.6972419172      3.24E-11
CDFT not converged.
  200   -1070.6972419165      3.65E-11    Convergence failure
 Lam   0.0287185184297142
 Lam   0.0333309260937862

 Q-Chem fatal error occurred in module scfman/scfman.C, line 5612:

 SCF failed to converge


 Please submit a crash report at q-chem.com/reporter
#2

According to the manual,
https://manual.q-chem.com/5.4/sect_CDFT-CI.html
you should either reduce the value of CDFT_THRESH or else use a denser integration grid.

#3

Is this possible to perform the CDFT of two diabatic states separately and read the wavefunction of both in one CDFT-CI calculation to calculate the coupling between the both?

#4

Unless this is described in the manual then probably not.

#5

The above mentioned manual example works if becke_shift is set to “unshifted”. Its does not work with any other change in the settings (grid or scf_convergence etc.). If does, the user should be made aware of that. It not, the manual example should be corrected/modified.