Qualitative modification of the high energy atomic photoionization cross section

It is demonstrated that the nonrelativistic high energy omega --> infinity behavior of the photoionization cross section of an nl atomic subshell, sigma (nl) (omega), for l > 0 is independent of l and is given by sigma (nl)(omega) similar to 1/omega (9/2) rather than the previously generally accepted sigma (nl)(omega) similar to 1/omega (l+7/2). Furthermore, for l = 1, although the exponent does not change, the coefficient is significantly altered. This modification of sigma (nl)(omega) is due to the interchannel interaction between ns photoionization channels and l not equal 0 channels in the atom. As a result, for the photoionization of l not equal 0 electrons, the single-particle approximation is never correct in the omega -- infinity limit. This has important consequences for sum rule calculations.