Table 8: Calculated interaction-energy without correction ( , kcal/mole), BSSE corrected energy of hydrogen-bond formation using counterpoise correction ( , kcal/mole) for DPG + water complex ( = 1, 2), and DPG dimer using 6-31++G(d,p) basis set and various methods.

Systems Methods

DPG + 1 water complex (GD)MP2−6.69−4.78
WB97XD−6.49−5.59
B3LYP DFT-D−6.83−5.87
M062X−6.67−5.74
M06−6.05−5.19
B3LYP−5.89−4.89
HF−4.90−4.20

DPG + 1 water complex (WD)MP2−7.39−5.28
WB97XD−7.39−6.61
B3LYP DFT-D−8.10−7.23
M062X−7.55−6.71
M06−6.77−6.02
B3LYP−6.09−5.31
HF−5.03−4.43

DPG + 2 water complexMP2−14.67−10.45
WB97XD−14.53−12.97
B3LYP DFT-D−16.07−14.33
M062X−14.94−13.26
M06−13.49−11.97
B3LYP−12.11−10.53
HF−9.95−8.74

DPG dimer
WB97XD−8.14−7.33
B3LYP DFT-D−8.85−7.93
M062X−7.53−6.67
M06−6.81−6.07
B3LYP−5.78−5.05
HF−4.97−4.26