What are ω and ν in this expression?

In the picture below a proportionality equation is shown:


$$\omega \propto \nu \exp\left(\frac{-\Delta G\_m}{RT}\right)\propto \dots$$


While $\Delta G\_m$ is the Gibbs free energy, $R$ is the gas constant, and $T$ is the temperature, what are the parameters $\omega$ and $\nu$ exactly?


![enter image description here](https://i.stack.imgur.com/lzOtH.jpg)


You can see the context on the picture: [Yttria-stabilized-zircona](http://en.wikipedia.org/wiki/Yttria-stabilized_zirconia).




$\Delta G\_m$ is the free energy barrier for the motion of atom from one site to another. The equation overall looks like a **transition state approach to this activated process**, and thus $\nu$ is the frequency at which this motion is attempted, i.e. a **$\nu$ is a characteristic lattice frequency**. In such models, it is often assumed to equal the Debye frequency.


Finally, **$\omega$ is the rate of transition from one site to another**, or something proportional to it (because the proportionality symbol is used rather than an equality). $\omega$ can be thus be the ionic conductivity, or a diffusion constant.


You can find the same expression and graph in [this chapter of undergrad lecture notes](http://www.uio.no/studier/emner/matnat/kjemi/KJM5120/v05/undervisningsmateriale/KJM5120-Ch5-Diffusion.pdf), for confirmation.


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