Anomalous Q EC-Values of Tz=1 Nuclei, 80Y, 84Nb and 88Tc

Beta decay end point energies of the T z =1 odd-odd nuclei, 80 Y, 84 Nb, 88 Tc were measured by using βγ-coincidences. The Q EC -values were deduced to be 6.2±0.6, 7.2±0.3 and 7.8±0.6 MeV for 80 Y, 84 Nb and 88 Tc, respectively. These values are more than 2 MeV lower than those predicted by most of the mass formulae. It is suggested that these anomalies may be partly attributed to residual p-n interactions of odd-odd nuclei.