Oscillator strengths for Mg+ transitions

Configuration interaction wavefunctions are used to derive oscillator strengths for transitions of the Mg+ ion, in particular that for the |3s²S→4p²P⁰| multiplet near 1240 Å. By comparing calculations of different complexity a value for the multiplet oscillator strength of 4 × 10−4 is found with an error estimate of ± 1 × 10−4. This is significantly lower than that generally used in studies of the interstellar medium and the implications of this are briefly discussed. Oscillator strengths for other transitions between 2S and 2P0 levels are also tabulated.