Relative intensities and polarizations in H2 rotational lines excited by electron impact

The relative values of the intensities and polarizations in H2 rotational lines in a band excited by electron impact are calculated in the united atom approximation by vector addition. They are valid at any electron energy beyond threshold. Experiments made on the 3p 3Π u → 2s 3Σ+g bands show reasonable agreement with the theory. Cascade effects are discussed.