The values quoted 9 are 2.19 and 2.26 respectively, which provides assurance that the Bigeleisen-Meyer equations, vibrational scaling and tunnelling corrections have all been independently implemented in the same way for both studies and also confirms that the quoted values were indeed obtained for the gas phase at 195K, since this condition was not explicitly stated. 9 The free energy difference indicates an exo/endo ratio of 6.275 and implementing these values into eqn. 1 gives a combined KIE195 = 2.22, which is essentially the simple mean of the endo/exo values (see Figure ).