Combined effect of cascade through circular orbits and Stark quenching on the decay of n=2→n=1 transition of H-like Fe in beam-foil excitation

- Circular orbits in H-like ions cascade down to 2p state and distort the decay curve.
- Stark mixing of 2s and 2p states would also deform the decay curve.
- Combined effect of cascading and Stark mixing is considered here.
- Lifetime of the 2s state reduces to 222 ps, from its natural lifetime of 350.6 ps.
- The value for electric field responsible for the Stark mixing is 7.1×106 V/cm.

Recently Mishra et al. (Mishra AP, et al. J Quant Spectrosc Radiat Transf 2013;120:114-9), while analyzing the effects of cascading through circular orbits (l=n−1)on the decay of unresolved 2p,2s→1s transitions of H-like Fe, neglected the effect of electric field at the exit surface of foil on the lifetime of the 2s state. In the present work we have considered the combined effect of cascading through circular orbits and the Stark mixing on the decay of the 2p,2s→1s transitions of H-like Fe in beam-foil excitation. It is observed that the natural lifetime of the 2s state (350.6 ps) is reduced to 221.8±22.4 ps due to Stark mixing of the long-lived 2s 2S1/2 state with the very close and short-lived 2pP1/2o2 state. The strength of the electric field responsible for such mixing comes out to be 7.09±0.37×106 V/cm. The results of the present work for cascading of circular orbits through the 2p state are in good agreement (within the error bars) with those obtained earlier by Mishra et al.