Effect of Li-like satellite lines and hyperfine structure on He-like 1s2p 3P20 level for 17⩽Z⩽50

We show that the satellite line blending greatly alters the lifetime of the level of interest if the lifetimes of the corresponding levels differ considerably. In the unresolved condition, one mistakenly measures the weighted average (effective) lifetime. We take an example of an unresolved Li-like M2 1s2s2p P5/204-1s22s2S1/2 and He-like M2 1s2p P203-1s2S01 transitions. In order to calculate the “effective” lifetime of these two levels we derive a simple but novel semi-empirical formula. The estimated effective lifetimes of various systems compare well with the lifetimes obtained from the satellite unresolved experiments for the 1s2p P203 level lifetime measurements. The influence of the hyperfine structure on this level has also been examined using this formula.