On the effective pairing-interaction strength in nuclei

An explicit formula expressing the pairing-interaction strength G by the pairing-energy gap parameter Δ-tilde, averaged over shell effects, is found in a uniform level-distribution model based on the harmonic oscillator potential. The dependence of G on the proton and neutron numbers, obtained from the formula in case of the phenomenological Δ-tilde(Δ-tilde=12 sub(-1/2) MeV), is discussed and compared with that assumed in various microscopic analyses in which G is numerically fitted to empirical odd-even mass differences. (author)