Hi Assume you could get absorption of a laser photon in unranium hexaflouride based on uranium 235 and not in 238. I can not imagine what I read in newspapers since the optical excitation would be almost the same. Rotational and vibrational spectrum however would differ by approximately 1% or less.
Even if an optical absorption can have an effect at say 2 µm according to http://jcp.aip.org/resource/1/jcpsa6/v16/i5/p442_s1?isAuthorized=no Makes the speed difference for one photon absorption to become v = 2hf/mc = 2h/m/lambda = 0.0011 m/s which is somewhat more realistic. But to what extent would collisions in the gas speed up heavier molecules and slow down the lighter ones? David David Jonsson, Sweden, phone callto:+46703000370
