. Author manuscript; available in PMC: 2014 Apr 9.

Published in final edited form as: J Chem Theory Comput. 2013 Mar 4;9(4):10.1021/ct400050d. doi: 10.1021/ct400050d

Table 3.

CCSD(T)-F12(b) energies at geometries optimized with M06-2X, RI-MP2, and XYGJ-OS for relatively small sized systems. The CCSD(T)-F12(b)/CBS energies at CCSD(T) optmized geometries are used as reference. The last column denotes the basis set used in the CCSD(T) optimization. Negative values for the formic acid dimer in XYGJ-OS means that, in the CCSD(T)-F12(b)/CBS potential energy surfaces, the XYGJ-OS geometry is lower in energy than the CCSD(T)/cc-pVTZ geometry.

		Nature	M06-2X	RI-MP2	XYGJ-OS
ammonia	- ammonia	H	0.04	0.06	0.05	cc-pVQZ
formic acid	- formic acid	H	0.10	0.05	−0.07	cc-pVTZ
water	- water	H	0.03	0.02	0.00	cc-pVQZ
ethene	- ethene	D	0.32	0.19	0.03	cc-pVQZ
methane	- methane	D	0.02	0.09	0.00	cc-pVTZ
ethene	- ethyne	O	0.25	0.13	0.02	cc-pVQZ

Average			0.18	0.06	0.02