Atomic data and spectral line intensities for Mg VI

Oscillator strengths and effective collision strengths for electron excitation of Mg VI

“…The target states included in the present scattering calculations are given in Table 1, where we compare our calculated excitation energies with the available experimental values and with recent calculations by Froese Fischer & Tachiev (2004) and Landi & Bhatia (2007). The overall agreement between experiment and present calculation is very satisfactory with an average deviation of about 0.034 Ry.…”

“…The accuracy of excitation energies from our extensive MCHF calculation for transition rates is somewhat better with average deviation of about 0.01 Ry. The present structure description represents a substantial improvement over those used in previous R-matrix calculations by Ramsbottom & Bell (1997) and distorted-wave calculations by Landi & Bhatia (2007). We obtained good agreement for all 2s 2 2p 3 , 2s2p 4 , 2p 5 , and 2s 2 2p 2 3l states, indicating that we consistently take correlation corrections in the ground and excited states into account, as our method allows us to use non-orthogonal orbitals, that are specific for given configurations.…”

“…For example, collision strengths of the dipole-allowed transitions at high electron energies are directly proportional to the oscillator strengths. We have presented our length values of oscillator strengths and transition probabilities in Table 2 where present results are compared with the calculations of Froese Fischer & Tachiev (2004) and Landi & Bhatia (2007). We used experimental energies in the calculations of oscillator strengths and radiative rates.…”

“…In astrophysical plasma applications, however, the majority of required radiative decay rates and collisional rate coefficients are derived from the A&A 548, A27 (2012) calculations. Previous theoretical calculations for electron impact excitation collision strengths include the distorted-wave calculations of Bhatia & Mason (1980), Bhatia & Young (1998), Landi & Bhatia (2007), and Zhang & Sampson (1999) and in the R-matrix calculations of Ramsbottom & Bell (1997). The distorted-wave calculations were carried out at a few selected incident electron energies and did not include resonances in the collision strengths.…”

“…The distorted-wave calculations were carried out at a few selected incident electron energies and did not include resonances in the collision strengths. Bhatia & Young (1998) and Ramsbottom & Bell (1997) considered the 12 lowest LS states of the 2s 2 2p 3 , 2s2p 4 , 2p 5 , and 2s 2 2p 2 3s configurations, while Landi & Bhatia (2007) included 74 fine-structure levels of the n = 2 and n = 3 states in their calculations.…”