Table 1.

Enthalpy changes (ΔH°(298 K)) and changes in Gibbs free energy (ΔG°(298 K)) between the ground singlet state and dissociative triplet state of phenol* determined with a few semi-empirical and post Hartree–Fock methods

	ΔH°(298 K) kcal mol−1	ΔG°(298 K) kcal mol−1
AM1**	85.93	84.96
PM6**	56.31	55.08
UMP2(Full)**	118.33	116.37
CBS-QB3	111.00	109.81
CBS-APNO	111.83	110.69
G3	111.14	109.95
G3B3	111.14	109.94
G3MP2	112.40	111.21
G4**	109.84	108.60

*Structures similar to a1 and a4 were fully optimized and thermochemical analyses carried out according to the respective methods.

**Gaussian 09^® B.01.³² on vayu.nci.org.au, was used for this work.