biochemistry - Is there a binding affinity metric for interactions not in equilibria?

I am investigating the strength of binding of a small peptide to a protein by isolating the bound version and subjecting it to collisions with gas molecules (CID mass spectrometry) to dissociate the complex.
When I plot the collision energy against the proportion of bound and unbound proteins I get a curve that looks like a K_d curve. However, as the interaction isn't in equilibria (i.e. it is in the gas phase) calculating the K_d value wouldn't be correct.

So is there another value I could calculate to describe the strength of the interaction?