The molecular geometries of all the reactants, transition states, intermediates, and products were fully optimized in gas phase by using the M06+2X density functional with the 6+31G(d, p) basis set
Based on the optimized structures obtained in gas phase, the single-point energies were further refined at the M06+2X/6+31++G(d, p) level of theory, with the solvent effects of THF simulated by the polarizable continuum model using the integral equation formalism variant (IEFPCM).
就是 the single-point energies 到 the Gibbs free energies 之间通过何种矫正转换的?