Excited state optimization and charge transfer stare

Questions
#1

Hello Developers and Users,

I need assistance in understanding the excited state optimization process. I am trying to optimize one of the structures of [OPP-3 --TEA]* system with different substituents. The initial structure shows partial charge transfer from TEA to OPP fragment in the first excited state. So, I followed the first excited state during the optimization. However, during the optimization process, I can see that the oscillator strength changes gradually, and after optimization, the first excited state is no longer the charge transfer state. Could you please check the files attached and advise on how I might achieve the correct optimized structure for this system? I have attached two figures that show energy and oscillator strength variations with optimization cycles.

Input file

$molecule
0 1
C     -4.8652486773      5.7630165861      2.3599803186
C     -4.6421325400      4.5167057749      1.4952138297
N     -3.4598808887      3.7671669129      1.8514974679
H     -4.9511817015      5.5254847011      3.4202574727
H     -4.0584136027      6.4845394333      2.2304855603
H     -5.5009453988      3.8418009110      1.5592539807
H     -5.7971115961      6.2297804350      2.0391540318
C     -3.3355202829      3.0765857085      3.1200682125
H     -2.7099193938      3.7095415650      3.7644430027
H     -2.7421503909      2.1822403838      2.9085631908
H     -4.5391335168      4.7955445786      0.4487919734
C     -4.6276286477      2.7043298384      3.8200519770
H     -5.2473994577      2.0832867041      3.1734804159
H     -4.3719569105      2.1255727526      4.7089739720
H     -5.2059056447      3.5703921177      4.1419241185
C     -2.2324141600      3.9768456212      1.1145378052
H     -1.6025611060      3.1017909922      1.2635567704
H     -2.4874247016      4.0302292570      0.0575655699
C     -1.4867395801      5.2461470443      1.5436488496
H     -0.5383480102      5.2713913552      1.0070680229
H     -2.0473298409      6.1475908225      1.2927591178
H     -1.2738040631      5.2432897726      2.6143931073
C      1.7966486678      0.7020429051      0.8989329218
C      2.6952489883      1.6576064219      0.3944664622
H      2.3201049070      2.4701322823     -0.2183732936
C      4.0512597787      1.6018651680      0.6849523570
H      4.7157951275      2.3590031835      0.2819386492
C      4.5591029304      0.5948847420      1.4994677665
N      5.9677155321      0.5526826191      1.7292502494
C      3.6858173813     -0.3603284299      2.0107785695
H      4.0643856925     -1.1608314916      2.6377367186
C      2.3317195860     -0.3112257414      1.7125189071
H      1.6798908520     -1.0889223509      2.0948532133
C      0.3610426327      0.7716553008      0.5937445625
C     -0.1201508253      1.3281531798     -0.6147461869
H      0.5919351432      1.6387896111     -1.3734829237
C     -1.4604713827      1.4475711594     -0.8859057068
H     -1.7539272239      1.8503230620     -1.8482855796
C     -2.4672849068      1.0471258984      0.0534506535
C     -1.9657303598      0.3831533239      1.2209467007
H     -2.6540960621     -0.0232405536      1.9524889168
C     -0.6166774266      0.2697422087      1.4744081680
H     -0.3056206925     -0.1982397723      2.4035947789
C     -3.8434106159      1.3898804828     -0.1006073492
C     -4.8557136869      0.9444906801      0.8149074276
H     -4.6034290430      0.2292195701      1.5887598762
C     -6.1693214638      1.3547486578      0.7128185164
H     -6.8961890723      0.9710489505      1.4235626425
C     -6.5799497578      2.2553339823     -0.2777584564
N     -7.9648895267      2.5648972306     -0.3590611928
C     -5.6192115909      2.6840183342     -1.2113701997
H     -5.9121219792      3.3591875262     -2.0102048355
C     -4.3078098242      2.2755878540     -1.1321656749
H     -3.6110096669      2.6433717373     -1.8763814264
C      6.8505009321      1.6884594191      1.9391918494
H      7.8817186321      1.3413046191      1.8731997494
H      6.7045223321      2.1169013191      2.9349608494
H      6.7012542321      2.4888155191      1.2002847494
H      6.3451344321     -0.1691504809      1.1329894494
C     -8.8137440267      1.6551067306     -1.1107913928
H     -9.8482653267      1.9825524306     -1.0060119928
H     -8.7428812267      0.6375819306     -0.7147103928
H     -8.5655581267      1.6198558306     -2.1814890928
H     -8.3209873267      3.5052554306     -0.2749413928
$end

$rem
basis = 6-311g**
cis_state_deriv = 1
job_type = optimization
method = wb97xd
geom_opt_dmax = 100
geom_opt_tol_gradient = 100
geom_opt_max_cycles = 80
max_cis_cycles = 100
cis_n_roots = 5
cis_singlets = 1
cis_triplets = 0
rpa = 2
mem_static = 4000
mem_total = 192000
solvent_method = pcm
scf_convergence = 8
symmetry = false
symmetry_ignore = 1
thresh = 14
$end

$pcm
heavypoints 590
method swig
radii bondi
solver inversion
theory cpcm
$end

$solvent
dielectric 2.03
opticaldielectric 2.01
$end

Output information-
Cycle 1

 Excited state   1: excitation energy (eV) =    3.1508
 Total energy for state  1:                 -1175.84032227 au
    Multiplicity: Singlet
    Trans. Mom.:  1.4289 X  -0.0642 Y   0.3563 Z
    Strength   :     0.1677310290
    X: D(  106) --> V(    1) amplitude =  0.9679
    X: D(  106) --> V(    4) amplitude = -0.2169

 Excited state   2: excitation energy (eV) =    3.8455
 Total energy for state  2:                 -1175.81479043 au
    Multiplicity: Singlet
    Trans. Mom.: -3.5137 X   0.5981 Y  -0.4500 Z
    Strength   :     1.2159880854
    X: D(  105) --> V(    1) amplitude =  0.9436

Cycle 61

 Excited state   1: excitation energy (eV) =    3.2657
 Total energy for state  1:                 -1175.87000358 au
    Multiplicity: Singlet
    Trans. Mom.: -4.4663 X   0.5579 Y  -0.7784 Z
    Strength   :     1.6693872472
    X: D(  106) --> V(    1) amplitude =  0.9671

 Excited state   2: excitation energy (eV) =    4.0915
 Total energy for state  2:                 -1175.83965829 au
    Multiplicity: Singlet
    Trans. Mom.: -0.1231 X   0.3101 Y  -0.3261 Z
    Strength   :     0.0218182863
    X: D(  104) --> V(    3) amplitude = -0.2623
    X: D(  106) --> V(    2) amplitude =  0.8784

energy_e_-5.13_2
energy_e_-5.13_2792×612 4.92 KB

strength_e_-5.13_2.0_0.7
strength_e_-5.13_2.0_0.7792×612 5.58 KB

#2

It seems like the diabatic character of the adiabatic state is probably changing during the optimization, which is not altogether uncommon. One approach to fix this is simply to stop the optimization, figuring out which adiabatic state you want, and restarting (with a different value of CIS_STATE_DERIV). Alternatively, you can try a state-tracking algorithm that attempts to follow the adiabatic state that best resembles the adiabatic state in the previous optimization step.
https://manual.q-chem.com/latest/sec_state_following.html

#3

Thank you so much, Prof. Herbert.

I have tried with your first suggestion – stop the calculation – use a different value for cis_state_deriv.

Separately, I wanted to explore the state-tracking algorithm for that, I added two extra specifications in the rem section

STATE_FOLLOW = TRUE
SET_STATE_DERIV = 1

The error occurs both in Q-Chem 5.4 and Q-Chem 6.0 as follows.

In Q-Chem 6.0.1, a few lines from the end

 ---------------------------------------------------
 Calculating Relaxed Density
 ---------------------------------------------------
 Iter    Rts Conv    Rts Left    Ttl Dev     Max Dev
 ---------------------------------------------------
   1         0           3      0.000349    0.000154
   2         0           3      0.000120    0.000055
   3         0           3      0.000037    0.000016
   4         0           3      0.000016    0.000008
   5         1           2      0.000004    0.000003
   6         3           0      0.000000    0.000000    Roots Converged
 ---------------------------------------------------
                Calling CISFollow
 ---------------------------------------------------

 Q-Chem fatal error occurred in module 0, line   45:

 Invalid job for state following

Error in Q-Chem run part 1

In Q-Chem 5.4, a few lines from the end

 ---------------------------------------------------
 Calculating Relaxed Density
 ---------------------------------------------------
 Iter    Rts Conv    Rts Left    Ttl Dev     Max Dev
 ---------------------------------------------------
   1         0           3      0.000349    0.000154
   2         0           3      0.000120    0.000055
   3         0           3      0.000037    0.000016
   4         0           3      0.000016    0.000008
   5         1           2      0.000004    0.000003
   6         3           0      0.000000    0.000000    Roots Converged
 ---------------------------------------------------
                Calling CISFollow
 ---------------------------------------------------
 Step:              0 State:             1
FileMan error: End of file reached prematurely reading (24) bytes in file FILE_CIS_S2
 Path: /tmp/SLURM_19658328/qchem16029/1200.0: No such file or directory

 Q-Chem fatal error occurred in module libmdc/newfileman.C, line 384:

 FileMan error: End of file reached prematurely reading (24) bytes in file FILE_CIS_S2
 Path: /tmp/SLURM_19658328/qchem16029/1200.0


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


Error in Q-Chem run part 1
```.
#4

Another user is also reporting that the state-following algorithm appears to be broken, starting with Q-Chem v. 6.0. (What version are you using?) I have submitted a bug ticket.