Theoretical investigation of spectroscopic properties of $W^{25+}$

TL;DR

This paper provides a theoretical analysis of the energy levels and emission spectra of the $W^{25+}$ ion using relativistic configuration interaction calculations, highlighting the importance of correlation effects on transition probabilities.

Contribution

It introduces large-scale relativistic configuration interaction calculations to study $W^{25+}$, emphasizing the role of correlation effects on spectral transitions and emission modeling in EBIT plasma.

Findings

Correlation effects are crucial for certain transitions.

Transition probabilities increase significantly due to correlation.

Predicted emission lines are observable in EBIT plasma.

Abstract

Energy levels and emission spectra of $W^{25+}$ ion have been studied by performing the large-scale relativistic configuration interaction calculations. Configuration interaction strength is used to determine the configurations exhibiting the largest influence on the $4f^{3}$, $4d^{9}4f^{4}$, $4f^{2}5s$, $4f^{2}5p$, $4f^{2}5d$, $4f^{2}5f$, $4f^{2}5g$, and $4f^{2}6g$ configuration energies. It is shown that correlation effects are crucial for the $4f^{2}5s \rightarrow 4f^{3}$ transition which in single-configuration approach occurs due to the weak electric octupole transitions. As well, the correlation effects affect the $4f^{2}5d \rightarrow 4f^{3}$ transitions by increasing transition probabilities by an order. Corona model has been used to estimate the contribution of various transitions to the emission in a low-density electron beam ion trap (EBIT) plasma. Modeling in 10--30 nm wavelength range produces lines which do not form emission bands and can be observed in EBIT plasma.