I have done a couple of calculations with this dispersion corrections and range separated functionals. The complex under study is Cinnamic---DMSO from XRD studies, where the ethylene group is 3.4 Angstroems from the S of DMSO (dimethylsulfoxide). The LMO-EDA ends up with reasonable energies, except for polarization energy that is way out of range
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ALL BASIS SET HARTREE KCAL/MOL
------------- wP57X-D / TZV
ELECTROSTATIC ENERGY ES= 35.155915 22060.69 kCal/mol ??
EXCHANGE ENERGY EX= 0.001502 0.94
REPULSION ENERGY REP= 0.020100 12.61
POLARIZATION ENERGY POL= -35.152773 -22058.72 kCal/mol ??
DFT DISPERSION ENERGY DISP= -0.008141 -5.11
TOTAL INTERACTION ENERGY HF OR DFT E= 0.016604 10.42
However using MP2 I get reasonable energies.
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ALL BASIS SET HARTREE KCAL/MOL
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ELECTROSTATIC ENERGY ES= -0.006687 -4.20
EXCHANGE ENERGY EX= -0.015563 -9.77
REPULSION ENERGY REP= 0.025771 16.17 kCal/mol
POLARIZATION ENERGY POL= -0.002422 -1.52 kCal/mol
MP2 DISPERSION ENERGY DISP= -0.005410 -3.40
TOTAL INTERACTION ENERGY HF OR DFT E= 0.001099 0.69
TOTAL INTERACTION ENERGY MP2 E= -0.004312 -2.71
Can anyone suggest a reason for that? Does anybody have a reference for H-bonds?
Thanks.
Article Energy Decomposition Scheme Based on the Generalized Kohn-Sham Scheme