MICROSCOPIC CALCULATION OF THE DETOUR CONTRIBUTION TO THE INTERNAL BREMSSTRAHLUNG SPECTRUM OF TL-204

A microscopic nuclear-structure calculation of the detour contribution to the internal bremsstrahlung spectrum of the first-forbidden unique electron-capture transition Tl-204(2g.s.-) --> Hg-204(0g.s.+) is carr ied out. The framework of the quasiparticle random phase approximation has been used to calculate the Gamow-Teller and electric dipole stren gth distributions in Tl-204 and Hg-204. Comparison of the present resu lt with the possible detour contribution deduced from experimentally k nown cases (Ca-41 and Ni-59) suggests that in general the detour trans itions could very well solve the long-standing discrepancy between the experimental and theoretical internal bremsstrahlung spectra.