Hello everyone.
I would like to calculate electronic coupling for PTCDI dimers. I did some calculation and got results that coupling between S1 states are very high numbers (2000-3000 cm^-1). In my system there is a double hydrogen bond, and I thought this might be a reason. And I did another calculation for pentacene dimer. Again the same situation. Then I looked at the example calculations on the manual for water cluster: in the output file attached there, there are coupling values of even several Hartrees. I would assume that this couldn’t be correct, right?.
Could anybody please help with this problem? Maybe I cannot interpret these results correctly, or something else.
Thank you in advance.
$molecule
0 1
--PTCDI 0
0 1
H 3.480049 0.704292 6.522990
H 3.398402 -1.249604 6.522990
H -3.158075 3.445305 6.522990
H 3.546431 3.163756 6.522990
H -3.446002 -3.424048 6.522990
H 3.257632 -3.706081 6.522990
H 0.330469 6.545219 6.522990
H -0.230910 -6.805995 6.522990
O -1.983489 5.684252 6.522990
O -2.464167 -5.753373 6.522990
O 2.563722 5.492612 6.522990
O 2.083046 -5.945014 6.522990
N 0.288182 5.529975 6.522990
N -0.188150 -5.791619 6.522990
C 0.110916 1.303158 6.522990
C -0.010002 -1.564328 6.522990
C -1.167823 0.657362 6.522990
C -1.229136 -0.812648 6.522990
C 1.330049 0.551481 6.522990
C 1.268259 -0.917650 6.522990
C 0.170400 2.732398 6.522990
C -0.069963 -2.992675 6.522990
C -1.029713 3.490935 6.522990
C 1.430504 3.387439 6.522990
C -1.329591 -3.648599 6.522990
C 1.130150 -3.751227 6.522990
C -2.317525 1.448837 6.522990
C -2.441493 -1.505536 6.522990
C 2.541920 1.245253 6.522990
C 2.417566 -1.710480 6.522990
C -2.252980 2.845569 6.522990
C 2.594825 2.642503 6.522990
C -2.494397 -2.902795 6.522990
C 2.353021 -3.107213 6.522990
C -0.989822 4.973237 6.522990
C -1.413839 -5.128738 6.522990
C 1.514282 4.868460 6.522990
C 1.089380 -5.234013 6.522990
H -3.297957 0.989317 6.522990
H -3.379604 -0.964580 6.522990
--PTCDI 1
0 1
H 1.895809 14.932566 6.522990
H 1.814162 12.978670 6.522990
H -4.742315 17.673579 6.522990
H 1.962191 17.392030 6.522990
H -5.030242 10.804225 6.522990
H 1.673392 10.522192 6.522990
H -1.253771 20.773493 6.522990
H -1.815150 7.422278 6.522990
O -3.567729 19.912526 6.522990
O -4.048407 8.474900 6.522990
O 0.979482 19.720885 6.522990
O 0.498806 8.283260 6.522990
N -1.296058 19.758248 6.522990
N -1.772390 8.436655 6.522990
C -1.473324 15.531431 6.522990
C -1.594242 12.663946 6.522990
C -2.752063 14.885635 6.522990
C -2.813376 13.415626 6.522990
C -0.254191 14.779754 6.522990
C -0.315981 13.310624 6.522990
C -1.413840 16.960671 6.522990
C -1.654203 11.235598 6.522990
C -2.613953 17.719209 6.522990
C -0.153736 17.615712 6.522990
C -2.913831 10.579675 6.522990
C -0.454090 10.477046 6.522990
C -3.901765 15.677110 6.522990
C -4.025733 12.722737 6.522990
C 0.957681 15.473526 6.522990
C 0.833326 12.517793 6.522990
C -3.837220 17.073843 6.522990
C 1.010585 16.870777 6.522990
C -4.078636 11.325478 6.522990
C 0.768781 11.121060 6.522990
C -2.574062 19.201510 6.522990
C -2.998078 9.099536 6.522990
C -0.069957 19.096733 6.522990
C -0.494860 8.994261 6.522990
H -4.882197 15.217591 6.522990
H -4.963844 13.263693 6.522990
$end
$rem
BASIS 6-31G*
EXCHANGE B3LYP
IQMOL_FCHK FALSE
CIS_N_ROOTS 1
CIS_TRIPLETS FALSE
AIFDEM_CTSTATES TRUE
AIFDEM TRUE
AIFDEM_EMBED_RANGE FULL_QM
AIFDEM_NTOTHRESH 99
NTO_PAIRS 1
MEM_TOTAL 40000
$end
Here I used FULL_QM, and pretty big system. I have another example for just water dimer, which gave the same high coupling values:
$molecule
0 1
--H2O 0
0 1
O 1.74078 1.59716 -1.49814
H 2.22908 2.18316 -2.08914
H 0.88038 2.04726 -1.32684
--H2O 1
0 1
O 1.388768 -1.849704 -1.917340
H 1.568668 -0.890104 -1.890440
H 1.759368 -2.186304 -1.077040
$end
$rem
BASIS 6-31G*
METHOD wB97X-D
CIS_N_ROOTS 3
CIS_TRIPLETS FALSE
AIFDEM TRUE
AIFDEM_EMBED_RANGE FULL_QM
AIFDEM_NTOTHRESH 90
NTO_PAIRS 1
MEM_TOTAL 8000
$end