1. For example, mass spectrometric investigations in which the gas within a small volume of the beam is ionized by electron bombardment.
2. It is assumed that the rate of collision, chemical reaction, or dissociation in the beam in negligible.
3. See Ramsey,Molecular Beams(Oxford University Press, London, 1956), and additional references given there.
4. Here and in the remainder of this note the indexidenoting the species is omitted, the equations apply to an arbitrary species in a mixture or to the single species in a one-component system.
5. The proof depends upon the fact that the logarithmic derivative of Γ(x) is a monotonic increasing function ofxfor x>0.