## Gibbs energy of activation (standard free energy of activation), $$\Delta ^{\ddagger}G^{\,\unicode{x26ac}}$$

https://doi.org/10.1351/goldbook.G02631
The standard Gibbs energy difference between the transition state of a reaction (either an elementary reaction or a stepwise reaction) and the ground state of the reactants. It is calculated from the experimental rate constant kvia the conventional form of the absolute rate equation: $\Delta ^{\ddagger}G = R\ T\ \left[\ln (\frac{k_{\text{B}}}{h}) - \ln (\frac{k}{T})\right]$ where kB is the Boltzmann constant and h the Planck constant (kB/h = 2.08358 x 10E10 K-1 s ). The values of the rate constants, and hence Gibbs energies of activation, depend upon the choice of concentration units (or of the thermodynamic standard state).