Table 1.

Comparison of the intermolecular interaction energies (kcal/mol) from OMC-ONIOM for MI and ab initio CCSD(T)/CBS calculations

layer-model	system1a		system2b
	case1c	case2d	case1c	case2d
high-Model1,1	−4.40	−4.40	−1.48	−1.48
high-Model1,2	−4.36	−4.36	−5.54	−5.54
low-Model1,1	−3.00	−3.81	−0.77	−0.87
low-Model1,2	−2.96	−3.75	−3.77	−5.04
low-real	−9.56	−10.31	−5.87	−7.04
OMC-ONIOM for MIe	−12.35	−11.51	−8.34	−8.16
ab initiof	−11.45	−11.45	−8.05	−8.05
Errorg	−0.90	−0.06	−0.29	−0.11

^awater trimer and water

^bAce-Ala-NMe and water

^cCCSD(T)/CBS:CP-MP2/cc-pVDZ

^dCCSD(T)/CBS:CP-MP2/arg-cc-pVDZ

^ecalculated from eq 5.

^fCCSD(T)/CBS, obtained by extrapolation using counterpoise corrected values for several basis sets^36,37

^gdifference between OMC-ONIOM for MI and ab initio energies