Optical determination of the J-dependence of angular momentum alignment in a heat conducting gas - Van den Oord, R.J.; De Lignie, M.C.; Beenakker, J.J.M.; Korving, J. (Elsevier)
We have directly observed the flow of angular momentum alignment in a heat conducting gas of rotating molecules (Kagan polarization). This alignment is measured as a function of the angular momentum, J, from the polarization of the laser-induced fluorescence of iodine gas. A difficulty to overcome is that the gas as a whole does not show alignment, so that the detection method must be able to distinguish between molecular fluxes parallel and antiparallel to the temperature gradient. This is achieved by making use of the relatively long lifetime of the excited I"2 molecule. The long standing question of the precise form of the angular momentum alignment with respect to the magnitude of J is now unambiguously answered for classical rotors: the Kagan polarization is proportional to J^2. Also the sign of the alignment has been determined.
http://linkinghub.elsevier.com/retrieve/pii/0378-4371(88)90051-9
Keywords: U