I am currently trying to run a FindFit command for some data I am analyzing. I can get the function to match my data using a manual manipulation, but I want to cross check the numbers that I am getting by manually altering the function with the computed numbers which FindFit outputs. When I attempt to run the following line
FindFit[normfktkmv, %251*Exp[-b*x], {A, D, W, b}, x]
Where %251 is
(A E^(-(wo^2/(W + 2 D x)^2)))/Sqrt[Abs[W + 2 D x]] /. wo -> 2
I get an error code which states "Failed to converge to the requested accuracy within 100 iterations" with the tag "FindFit". I have not been able to fix this problem on my own. Any suggestions on how to fix this issue? I have included an image of the function plotted manually below.