publishing fit data

Help please …..I am preparing a paper for publication with some data fitted using the IGOR double exponential x offset fit.
The software quotes an ‘equation’ that is not an equation
y_0+ A_1 exp⁡{(-(x-x_0 ))/τ_1 }+A_2 exp⁡{(-(x-x_0 ))/τ_2 }
and that has no definitions of the variables, is there a better description/ definition of the fit technique with suitable references for publication
thanks
The equation is y = y_0+ A_1 exp⁡{(-(x-x_0 ))/τ_1 }+A_2 exp⁡{(-(x-x_0 ))/τ_2 }

The meaning of the constants should be obvious. y_0 is the y offset, x_0 is the x offset, tau_i is some sort of time constant to describe the decay rate. A_i scale the two exponentials.

Your two time constants should be fairly well separated for this to work.

Is there some reason you chose the double exponential equation to fit the data? Generally one would have some model (in which case the fitted parameters would have obvious meaning) that you wanted to fit the data to. If that's not the case, then you have some physically meaningless fit that probably doesn't actually tell the reader anything useful, and all you've done is add parameters on until you got an equation that could be forced to fit the data (kind of like adding more and more terms onto a polynomial until it fits the data - of course it works but it doesn't tell you anything).