The standard @G02629@ difference between the @T06468@ of a reaction (either an @E02035@ or a @S05970@) and the @G02704@ of the reactants. It is calculated from the experimental @O04322@ \(k\) via 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 \(k_{\text{B}}\) is the @B00695@ and \(h\) the @P04685@ (\(\frac{k_{\text{B}}}{h} = 2.083\ 58\times 10^{10}\ \text{K}^{-1}\ \text{s}^{-1}\)). The values of the rate constants, and hence Gibbs energies of @A00093@, depend upon the choice of concentration units (or of the thermodynamic @S05925@).