The tetrahedral and octahedral complex ions TcO4-, TcCl62-, TcBr62-, TcI62-, which exhibit experimentally determined decay constant variations of Tc-99 m [1], meet the conditions for the application of the Xα-SW-method. The results of the calculations are given, including the case of TcF62-. The decay constant variations are evaluated using the one-electron functions in a partial-wave expansion. The results are compared with the measured values and a detailed discussion gives a comprehensive picture of the decay constant variation induced by the chemical surroundings considered. © 1979 Springer-Verlag.
