Hi There, I have been working on fluorescence decays of the fluorophores whose lifetimes are comparable to the instrument response function(IRF) of my device. The technique I use is based on Time-correlated single photon Counting(TCSPC). I have been fitting the decay curves using multiple exponentials in Origin 8, which fits it on the basis of Non-linear least square fitting(NLSF) method. However, the fit is independent of any information about IRF. My perception was that though the NLSF method doesn't take IRF into account, but because it fits only to the exponential forms, and indirectly it implies that it would not fit the non-exponential forms of IRF. Thereby fitting the data along with deconvolution, in which case it would never need to know the IRF. I was just wondering if Iam right in thinking so or do I have to go for deconvolution first followed by fitting. Any source of code for deconvolution and fitting would be very much appreciable. Thanks all, Sunny.