Theoretical calculation of the isoelectronic line ratio of Li-like Ti and Cr under different mixture ratios

Abstract

With the consideration of coronal conditions, a simplified model and the steady-state rate-equation are used to calculate the isoelectronic line ratio for 1 s 22 p( 2 P 3/2)→1 s 22 s( 2 S 1/2) transition in Li-like Ti and Cr from the electron temperature 400 to 1100 eV . The relation between the isoelectronic line ratio and the electron temperature are provided under different mixture ratios of Ti and Cr. Then, the mixture ratio from 2:1 to 3:1 between Ti and Cr are obtained that are suitable for the electron temperature diagnostic by using isoelectronic line ratio of Li-like Ti and Cr. The relative abundance of two close ionization stages, which is from bare nucleus to Be-like ionization stage, are given and show that the He-, Li- and Be-like are the principal ionization stages from 400 to 1300 eV for Ti and from 500 to 1300 eV for Cr. The Li-like charge state will reach the maximum distribution approximately from 400 to 649 eV for Ti and from 547 to 900 eV for Cr. The paper also shows that the dielectronic recombination and spontaneous radiative recombination rates only have small effects on the isoelectronic line ratio in the electron temperature 400– 1100 eV .