This has been a point of confusion Here are the conventions used in a few of the classic SAXS text vs. recent reviews:
-------------- I believe Guinier actually used the variable "u" in his thesis, but must have changed at some point (I don't have it handy to check at the moment). Guinier & Fournet (1955) h = 4pi Sin(theta)/lambda where 2*theta = scattering angle Glatter & Kratky (1982) (including chapters by Porod and other authors) h = 4pi Sin(theta)/lambda --- so "h" makes sense if one is familiar with crystallography derivations. Feigin & Svergun (1987) s = 4pi Sin(theta)/lambda The notation "s" seems to come from the notation for "scattering" vectors. Svergun publications consistently use s this way, though the software can define s with or without the 2pi and in either inverse nanometers or inverse Angstroms. In my experience very few use 2Sin(theta)/lambda, though it is more familiar to crystallographers as the inverse of the d-spacing. But "q" is widely used in BioSAXS: Putnam, Hammel, Hura & Tainer (2007) q = 4 pi Sin(theta)/lambda Jacques and Trewhella (2010) q = 4 pi Sin(theta)/lambda Why q? I haven't traced it back yet. From generalized coordinate of classical mechanics maybe? On Jun 30, 2011, at 3:37 AM, James Stroud wrote: > Hello All, > > Is there precedent or a conventional shorthand (e.g. greek letter) for > sin(theta)/lambda? > > Thanks in advance for any help or suggestions. > > James
