Critically Evaluated Spectral Data for Singly Ionized Carbon (C II)

TL;DR

This paper provides a comprehensive, critically evaluated compilation of spectral data for singly ionized carbon, including energy levels, transition probabilities, and isotope shifts, based on extensive experimental and theoretical analysis.

Contribution

It offers the first critically assessed and extensively re-evaluated spectral data set for C II, including new energy levels, transition probabilities, and improved ionization energy measurements.

Findings

Compiled 597 spectral lines and 972 transitions.

Derived 414 optimized energy levels with least-squares fitting.

Extended transition probability tables with new calculations.

Abstract

All available experimental data on the spectrum of singly ionized carbon have been critically analyzed. Measurement uncertainties of all published studies have been re-assessed. The scope of observational data includes laboratory emission spectra of arcs, sparks, electrodeless discharges, and hollow cathode lamps recorded with grating and Fourier transform spectrometers, laboratory photoabsorption spectra, and emission spectra of planetary nebulae. The total number of observed spectral lines included in this compilation is 597. These lines participate in 972 transitions. From this list of identified transitions, we have derived a set of 414 energy levels, which are optimized using a least-squares fitting procedure. The identifications are supported by parametric calculations with Cowan's codes. The existing tables of critically evaluated transition probabilities have been extended with our newly calculated data. The ionization energy has been derived from the newly optimized energy levels with improved precision. Data on isotope shifts and hyperfine structure have also been compiled.