Editing Forster distance calculator (section)

== Input values ==
The calculation needs input for:
* '''Qd''': Fluorescence quantum yield of the donor in the absence of the acceptor.
*: This is normally provided from the manufacture, and this information is normally also available in the [http://www.spectra.arizona.edu/ database].
*: It is recognized in the literature, that the value for '''Qd''', changes on behalf on which position its located on the protein.
*: Changes in 5-10 % is normal, but much larger values can be expected if the dye make hydrophobic interactions with the protein. This is dye-nature dependant.
*: This value can only be determined precisely with experiments for the protein at hand.
*: But anyway, for a "starting" selection for a FRET pair, the manufacture '''Qd''' should be "ok".
* '''Kappa2 = 2.0/3.0''': Dipole orientation factor.
*: In the literature, I often see this equal 2/3=0,667 This corresponds for free diffusing dye.
*: For a dye attached to a protein, and restricted in one direction, the value is equal Kappa2=0.476
*: But since we take the 6th root of the value, the difference ends up only being 5% in relative difference for the R0 value.
*: Kappa2=2/3 can be a valid fast approximation, for the purpose of ordering dyes. But be careful and check the literature for discussions.
* '''n = 1.33''': 
*: water=1.33, protein=1.4, n(2M GuHCl)=1.375
*: Again, we take the sixth root, so the differences are "not so important".