I want to write a code for Fano lineshape fit.

I want to fit Fano resonance with experimental data. The formula for Fano resonance is

R = | p(w) + (A . G. exp(i.o) / [w - w0 + i.(g + G)])| ^2

p(w) is also a complex valued. Plot is b/w R & w. Other values also need to find to get correct fit.

I did some basic liner fit using polyval, polyfit. I have no idea how do I fit this complex expression with multiple variable.

[Alex Sha]

Hi, post your data file and the details of function you want to fit.

[Alex Sha]

Hi, just don't understand what the means of "Wavelength Reflectivity" in your Excel data file? which one is independent variable? which one is dependent variable?, what is your fitting function?

[Arjun Upadhyay]

Hi, wavelength( energy) is the independent variable and Reflectivity is dependent. The fitting function is mentioned above as Fano formula and also given in attached pdf under eq 2.28.

Answer 1

[Alan Stevens]

Create a function that calculates the sum of squared differences (SS) between your function and the measured values, and then use fminsearch to determine the values of your variables that minimize SS?

Try help fminsearch to see if it will do what you want.