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

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