partial decay constant

in nuclear chemistry
https://doi.org/10.1351/goldbook.P04410
For a @[email protected]: the @[email protected] in unit time for the decay of one of its nuclei by one of several modes of decay.
Source:
PAC, 1982, 54, 1533. (Glossary of terms used in nuclear analytical chemistry (Provisional)) on page 1547 [Terms] [Paper]