There are three differences of CNEO-TST from CTST. First, the Born-Oppenheimer potential energy surfaces 77 are replaced by the CNEO effective potential energy surfaces. This affects the potential along the reaction path, the vibrational frequencies (which are calculated from CNEO Hessians 83 ), the rotational PFs (which are calculated using CNEO optimized geometries), and the electronic PFs (which are calculated using CNEO energies).