More in details I have to deal with a function that depends on both the chi and xmu data. I tried to look at all the chances and through the guide but I didn't find any function to do that. I was thinking of exporting separately the .chi and .xmu data, but they have different point of the Energy(eV) and that makes hard the programming of my evaluating scripts. 
Should I use the spline function to estimate the .xmu data and use it combined to the .chi data?

Hope it's all clear. Thanks
Best Regards,
Matteo, UiS