I am trying to calculate electronic coupling by using CDFT-CI method, but I’ve encountered two issues.
The first question is about the keyword CDFTCI_SKIP_PROMOLECULES. When should this keyword be added? During my calculations, when I included this keyword, the computation time increased significantly, and the results differed substantially from those obtained without it. The manual mentions “Skips promolecule calculations and allows fractional charge and spin constraints to be specified
directly.,” but I didn’t quite understand its significance.
The input goes as follows,
$rem
symmetry false
sym_ignore true
METHOD wb97x-d
BASIS 6-31+G*
SCF_CONVERGENCE 8
MAX_SCF_CYCLES 200
UNRESTRICTED TRUE
CDFTCI TRUE
CDFTCI_SKIP_PROMOLECULES （TRUE OR FALSE）
CDFT_THRESH 7
$end
The second question pertains to the principle of calculating coupling in CDFTCI. In the CDFTCI method, when calculating couplings, does the magnitude of the coupling depend solely on the overlap of the electronic wavefunctions, or are there other factors at play?
help (To meet this requirement, these words must gather in groups of no fewer than 20 characters before they can party together in the comment section)
Please specify a complete input file if you’d like someone to take a look at this.
$molecule
-1 2
C -0.65895500 1.30712900 -2.83204500
C -0.37611900 0.39879400 -1.80720400
C -1.36907300 -0.02585500 -0.92908100
C -2.68866000 0.44880200 -1.10106700
C -2.96239800 1.34156500 -2.13354700
C -1.95021900 1.77884900 -2.99376900
C -3.47770300 -1.14103900 0.56736100
C -2.15747700 -1.60955800 0.74207200
C -1.93306400 -2.75488500 1.50010500
H -0.91863600 -3.11565100 1.62650500
C -2.99523000 -3.42772500 2.11163800
C -4.28919900 -2.96245800 1.94942200
C -4.52840400 -1.82510000 1.17160200
H 0.14013900 1.63098400 -3.49101200
H 0.63225600 0.02310200 -1.68289300
H -3.97235200 1.71427200 -2.25855200
H -2.18968600 2.48536500 -3.78144800
H -2.79306700 -4.31003600 2.70981500
H -5.12479400 -3.46970800 2.42018900
H -5.54147400 -1.46049900 1.04760900
N -3.67746500 0.03851100 -0.18164600
N -1.10272800 -0.87851100 0.15987200
C -5.01835300 0.50232800 -0.37233900
C -5.83989600 -0.09034500 -1.33311800
C -5.49451100 1.54955900 0.41164600
C -7.14165700 0.36977500 -1.50720600
H -5.44890800 -0.90669900 -1.93438600
C -6.79925400 2.00787700 0.23486500
H -4.83760100 1.99479600 1.15243000
C -7.62170300 1.41925900 -0.72294100
H -7.78152400 -0.08986100 -2.25363900
H -7.17114500 2.82415200 0.84573700
H -8.63721000 1.77699100 -0.85967700
C 0.24229800 -1.25356300 0.46681300
C 0.83317300 -0.75472700 1.62576200
C 0.94792700 -2.12847300 -0.36211000
C 2.13469800 -1.12951800 1.95514600
H 0.27220700 -0.06995700 2.25522700
C 2.25661500 -2.47907000 -0.04319000
H 0.46766600 -2.51703400 -1.25600800
C 2.84958100 -1.98252400 1.11797000
H 2.59687300 -0.72668600 2.85200300
H 2.81534300 -3.13722800 -0.70038500
H 3.87325200 -2.25220400 1.35959000
C 5.28794600 0.43931300 0.37557700
C 4.70145800 0.13546300 -0.84983600
C 3.43029200 0.60695600 -1.16973800
C 2.72498000 1.36917100 -0.24623100
C 3.30775800 1.63462800 0.98802300
C 4.58715300 1.19648200 1.30822300
H 6.28316300 0.07609400 0.61021000
H 2.98948000 0.37443000 -2.13423500
H 1.72575800 1.72861700 -0.46744600
H 5.01920300 1.42530000 2.27568100
Br 2.28868800 2.53942100 2.29855000
C 5.41228000 -0.78987200 -1.79049500
F 5.16926300 -2.07946200 -1.48683900
F 6.74336700 -0.63094800 -1.74235700
F 5.02877100 -0.61244500 -3.06258000
$end
$rem
symmetry false
sym_ignore true
METHOD pbe0
BASIS 6-31G*
SCF_CONVERGENCE 8
MAX_SCF_CYCLES 200
UNRESTRICTED TRUE
CDFTCI TRUE
CDFT_THRESH 7
$end
$cdft
0
1.0 45 59
0
1.0 45 59 s
1
1.0 45 59
1
1.0 45 59 s
$end
Here is the input file. The coupling value calculated from this input is 0.0034480. If the CDFTCI_SKIP_PROMOLECULES TRUE keyword is added, the coupling value becomes 0.0010655. How can this difference be explained? Which result is reliable?
can you use the preformatted text box, </> ? Otherwise there are special characters missing from your input file.