Forster Distance Calculator

Calculates the Forster distance from the absorption spectrum of the acceptor and the fluorescence spectrum of the donor (and knowledge of the donor fluorescence quantum yield and acceptor extinction coefficient). The program will automatically interpolate the data so the data can be collected with different pitches along the wavelength axis (i.e. 1nm increment for fluorescence and 0.5 nm increments for absorption).  The user also needs to supply an estimate for kappa-squared (orientation factor) and the index of refraction between the donor and acceptor.  Several 

interpolation and integration options are available (although I’ve yet to come across a case where this makes an appreciable difference).

Download the Mac version here.  Some absorption and emission spectra of Alexa dyes in CSV format are in this folder.