Breit-Pauli R-matrix calculation of the 3p photoabsorption of singly ionized manganese

The 3p photoabsorption of Mn II is studied using a Breit-Pauli R-matrix approach for the purpose of establishing the structure of the 3p --> 4s resonance triplet. The results favour the hypothesis put forward by Dolmatov that the experimental spectrum obtained by Cooper et al for this ion was not entirely pure. Satisfactory agreement is found for the positions of resonances compared with those of Cooper er al and the energy level calculation of Quinet and Hibbert. A more complete identification of resonances is obtained in comparison with earlier work.