Recalculation of Mass Defects

Abstract

THE well-known mass defect curve of the old nuclear scheme calculated with regard to α-particles and protons presented a difficulty with its minimum of binding energy for tin and an increasing portion between tin and lead. On the other hand, the mass defect values against protons give a rather smoothly decreasing curve.¹ As has already been pointed out,² the number of α-particles must be considerably reduced from the point of view of the new scheme, which does not admit any electrons in nuclei, but only neutrons and protons (presumably joined as α-particles). The curve of mass defect against protons and neutrons (perhaps with a single ‘central’ α-particle) is very similar to the old curve against protons, but decreases less rapidly. Clearly the new mass defect values relatively to α-particles, neutrons and protons must lie somewhere between the old values computed relative to protons and α-particles respectively (because the number of α-particles is decreased). We may emphasise that this new mass defect curve shows no increasing portion between tin and lead. For illustration we give two typical values: Old: 50Sn¹²⁴ = 31α + 12ɛ; mass defect = 0.158 (in mass units); 82Pb²⁰⁸ = 52α + 22ɛ; mass defect = 0.035. New: 50Sn¹²⁴= 25α + 24w (w = neutron); mass defect = 0.304; 82Pb²⁰⁸ = 41α + 44w; mass defect = 0.366.