Comment on ''proton single-particle reduced widths for unbound states''

In a recent paper, Iliadis, C. (ibid., vol.618, p.166, 1997) has estimated values of proton single-particle reduced widths for unbound states, for a range of target masses, bombarding energies, nl values and channel radii. These are ''observed'' values, in the sense of Lane and Thomas. Here ''formal'' values are calculated from an R-matrix formula, for the same range of parameter values. The formal values are more useful in general, and those obtained here differ appreciably from the observed values of Iliadis. Comparison is also made with values derived from phase shifts calculated using an optical potential. (orig.)