Atomic Transition Probabilities for UV and Optical Lines of Tm II

TL;DR

This paper presents new measurements of atomic transition probabilities for Tm II in UV and optical wavelengths, providing more accurate data for astrophysical applications and stellar abundance analysis.

Contribution

It reports the first measurements of branching fractions for 35 Tm II levels and refines transition probabilities with improved accuracy, enhancing atomic data for astrophysics.

Findings

New transition probabilities for 224 Tm II lines with 5-30% accuracy.

First-time measurements for 35 high-lying energy levels.

Consistent stellar abundance derived from new data.

Abstract

We report new branching fraction measurements for 224 ultraviolet (UV) and optical transitions of Tm II. These transitions range in wavelength (wavenumber) from 2350 - 6417 Angstroms (42532 - 15579 cm-1) and originate in 13 odd-parity and 24 even-parity upper levels. Thirty-five of the 37 levels, accounting for 213 of the 224 transitions, are studied for the first time. Branching fractions are determined for two levels studied previously for comparison to earlier results. The levels studied for the first time are high-lying, ranging in energy from 35753 - 54989 cm-1. The branching fractions are determined from emission spectra from two different high-resolution spectrometers. These are combined with radiative lifetimes reported in an earlier study to produce a set of transition probabilities and log(gf) values with accuracy ranging from 5 - 30%. Comparison is made to experimental and theoretical transition probabilities from the literature where such data exist. These new log(gf) values are used to derive an abundance from one previously unused Tm II line in the UV spectrum of the r-process-enhanced metal-poor star HD 222925, and this abundance is consistent with previous determinations based on other Tm II lines.