Critically Evaluated Spectral Data for Neutral Carbon (C I)

TL;DR

This paper provides a comprehensive and critically evaluated compilation of spectral data for neutral carbon, including energy levels, wavelengths, and transition probabilities, combining experimental data with parametric calculations for improved accuracy.

Contribution

It offers the first unified, critically evaluated dataset of neutral carbon spectral lines, energy levels, and transition probabilities, with new predictions and refined ionization limits.

Findings

Optimized 412 energy levels with 1221 observed lines

Provided transition probabilities for 1616 lines, including 241 new ones

Determined a more accurate ionization limit at 90,820.348(9) cm^(-1)

Abstract

In this critical compilation, all known to us experimental data on the spectrum of neutral carbon were methodically evaluated and supplemented by parametric calculations with Cowan's code. The sources of experimental data vary from laboratory to astrophysical objects and employ different instrumentation from classical grating and Fourier transform spectrometers to precise laser spectroscopy setups and various other modern techniques. This comprehensive evaluation provides accurate atomic data on energy levels and wavelengths (observed and Ritz) with their estimated uncertainties, as well as a uniform description of observed line intensities. In total, 412 energy levels were optimized with the help of selected 1221 best observed lines participating in 1365 transitions in the wavelength region 750 {\AA} to 609.14 {\mu}m. In addition, 737 possibly observable transitions are predicted. Critically evaluated transition probabilities for 1616 lines are provided, of which 241 are new. With the accurate energy levels obtained, combined with additional observed data on high Rydberg states, the ionization limit was determined to be 90 820.348(9) cm^(-1) or 11.2602880(11) eV in fair agreement with the previously recommended value, but more accurate.