Evidence of anomalous multiplet line shapes in optically thick,laser-produced plasmas

We report observations of anomalous line shapes for the transitions 2p?3d (²P?²D) emitted by the Li-like ions N(V), O(VI), F(VII) in laser-produced plasmas. These transitions are normally doublets but show completely different characteristics (e.g., triplet structures or invension of two-component intensity ratios) in the plasmas. The observed line profiles are accounted for in terms of opacity and Doppler effect produced by plasma expansion. This interpretation is independent of the particular transition involved, i.e., multiplet structures can generate more complicated features with various unexpected new components, anomalous intensity ratios, etc.