Hello!
I have a problem when I am trying to compute a CH4 + H system with DFT. I use the fonctional PBE0 and take into account the dispersion correction from Grimme.
I tested 2 different versions of NWCHEM ( 6.1 and 6.3) and I have 2 different results for the energy.
Here is my input in both cases :
C
H1 C r1
H2 C r2 H1 h
H3 C r2 H1 h H2 120.0
H4 C r2 H1 h H2 -120.0
X H1 rx C 90.0 H2 0.0
H5 H1 rq X 90.0 C 180.0
variables
r1 1.089
r2 1.089
h 109.5
constants
rx 1.0
rq 10.0
end
end
charge 0
basis
H library 6-31g**
C library 6-31g**
end
dft
odft
mult 2
xc pbe0
disp vdw 3 s6 1.00
direct
end
task dft energy
and here is my output for NWCHEM 6.1 :
s6 scale factor = 1.000000000000
s8 scale factor = 0.928000000000
sr6 scale factor = 1.278000000000
sr8 scale factor = 1.000000000000
vdW contrib = -0.000085129806
Total DFT energy = -40.961508464208
One electron energy = -81.323611922722
Coulomb energy = 33.599927702454
Exchange-Corr. energy = -7.162775212205
Nuclear repulsion energy = 13.925036098071
Numeric. integr. density = 11.000001670723
and for NWCHEM 6.3 :
Total DFT energy = -42.396050185008
One electron energy = -80.870874434116
Coulomb energy = 33.373566689696
Exchange-Corr. energy = -7.162775212673
Nuclear repulsion energy = 13.698659623376
Dispersion correction = -1.434626851290
Numeric. integr. density = 11.000001541627
Total iterative time = 5.5s
Can you tell what is wrong?
Thank you very much!!
Guillaume
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