Hello,

I am trying to calculate the binding energy between a benzene molecule and methylene blue(+1 charge) in PI stacking.
Some experimental value I got gives around 6 Kj/mol. With normal DFT I get around 5Kj/mol but with DFT-D
I get 30Kj/mol!, this including BSSE error. Question: 1. Why am I getting such a huge difference, when adding
DFT-D should give a better description?. 2. Can I just go for DFT and ignore DFT-D in this case?.

Thanks!,
Axell

I attach below my current $rem:

$rem
JOBTYPE Opt
EXCHANGE B3LYP
BASIS 6-311+G*
scf_convergence 8
unrestricted true
DFT_D empirical_grimme3
basis_lin_dep_thresh 7
$end