In this paper we report energies for 54 levels among the (1s²2s²2p⁶) 3s²3p⁵, 3s3p⁶, 3s²3p⁴3d and 3s3p⁵3d configurations of Fe X, and results for radiative rates, oscillator strengths, and line strengths for electric and magnetic dipole and quadrupole transitions among these levels. Additionally, life-times of the excited levels are calculated and compared with the available measured values. The earlier results are of Bhatia & Doschek (BD: [1]), and Deb et al (DGM: [2]). BD included configuration interaction (CI) among the basic 4 configurations only, but DGM included extensive CI, and therefore, their results should be the most accurate available to date. However, dierences between the two sets of energies are up to 11%. Therefore, our aim is to explain these dierences, and to assess the accuracy of the available atomic data. Additionally, DGM reported radiative rates for only E1 transitions, whereas corresponding results for E2, M1 and M2 transitions are also required in the modelling of plasmas. Therefore, in this paper we report radiative rates for all types of transitions. For our calculations, we have adopted the fully relativistic GRASP code [3]. A test calculation performed with only the above 4 configurations produced energy levels within 1% with those of BD. However, inclusion of additional CI with the 3p⁶3d, 3s3p⁴3d², 3s²3p³3d² and 3s²3p²3d³ configurations, especially of 3s²3p³3d², lowers the energies by ∼0.7 Ry. Therefore, our conclusion is that for a reasonably accurate calculation of energy levels for Fe X, inclusion of CI among the 3s²3p⁵, 3s3p⁶, 3s²3p⁴3d, 3s3p⁵3d, 3p⁶3d, 3s3p⁴3d², 3s²3p³3d² and 3s²3p²3d³ configurations is necessary, and the effect of other neglected configurations is insignificant. The detailed results along with comparisons will be presented during the conference. However, our energy levels are estimated to be accurate to ∼3%, whereas results for other parameters are probably accurate to ∼20%. Additionally, the agreement between measured and calculated life-times is better than 10%. Furthermore, our calculations confirm the accuracy of the results of DGM, but the BD energies are overestimated by up to 11%. Finally, DGM suspected the NIST ordering of the 3s²3p⁴(³P)3d ⁴F_3/2 and 3s²3p⁴(¹D)3d ²P_3/2 levels to be a misprint, whereas our calculations confirm the NIST ordering to be correct.

References