Electron impact excitation cross-section of Be-like Ni XXV ion in plasma environment

Introduction: The study of spectral properties and electron impact excitation in plasma environments has gained significant attention due to its wide range of applications, such as astrophysical bodies, inertial confinement fusion experiments, high-density spectroscopy applications, and X-ray free-electron laser experiments.

Methods: We employed the relativistic configuration interaction (RCI) technique and the relativistic distorted wave (RDW) method implemented in the Flexible Atomic Code (FAC). To account for plasma effects, both the temperature-dependent ion-sphere potential and the quantum plasma potential are incorporated.

Results and Discussion: The plasma screening effect on spectral properties and electron impact excitation cross-sections of Be-like Ni XXV ion embedded in plasma environment has been calculated. Plasma screening effects on transition energies and decay rates corresponding to the resonance and inter-combination transitions 2snp ^3,1P₁→ 2s^{2 1}S₀ (n = 2,3) of Be-like Ni XXV ion are investigated. Further, we also study the effect of plasma density on excitation cross sections of Be-like Ni XXV ion embedded in dense plasma. The accuracy of our present results has been validated by comparing the calculated energies with the energies available on the NIST database and other available theoretical data, which shows good agreement with the reported values.

Conclusions: We observed blue shifts in the transition energies for transitions with Δn = 0 and red shifts for those with Δn ≠ 0. The electron impact excitation cross-sections decrease with increasing incident electron energy and with increasing plasma density.