ExoMol line lists XXXI: spectroscopy of lowest eights electronic states of C2

Abstract

Accurate line lists for the carbon dimer, C 2 , are presented. These line lists cover rovibronic transitions between the eight lowest electronic states: energy curves (PECs) and transition dipole moment curves are computed on a large grid of geometries using the aug-cc-pwCVQZ-DK/MRCI level of theory including core and core-valence correlations and scalar relativistic energy corrections. The same level of theory is used to compute spin-orbit and electronic angular momentum couplings. The PECs and couplings are refined by fitting to the empirical (MARVEL) energies of 12 C 2 using the nuclear-motion program Duo. The transition dipole moment curves are represented as analytical functions to reduce the numerical noise when computing transition line strengths. Partition functions, full line lists, Landé-factors and lifetimes for three main isotopologues of C 2 ( 12 C 2 , 13 C 2 and 12 C 13 C) are made available in electronic form from the CDS

Carbon stars with increased oxygen and nitrogen abundances: hydrostatic dust-free model atmospheres

“…In this context we also want to note that our preliminary tests with the new C 2 linelist from Yurchenko et al (2018), which is considered to be more complete and accurate than the old one published by Querci et al (1974), confirm our conclusion. The scaling used in the 2009 grid should not be applied, since it makes the predicted spectra worse.…”

“…The scaling used in the 2009 grid should not be applied, since it makes the predicted spectra worse. The data of Yurchenko et al (2018) will become part of the standard opacity setup for the next generation of COMA calculations. Figure 11.…”

Constraining the thermally pulsing asymptotic giant branch phase with resolved stellar populations in the Large Magellanic Cloud

“…Compared to the original grid of Aringer et al (2009) the inclusion of these data in the calculation of atmospheric models and observable properties causes significant changes in the pressure-temperature structures, synthetic spectra and photometric colours. The largest effects are due to new linelists for C 2 (Yurchenko et al 2018) and C 2 H 2 (Chubb et al 2020), computed as part of the ExoMol project (Tennyson et al 2016). Updated opacities were also published for HCN (Barber et al 2014), CH (Masseron et al 2014) and the lower levels of CN (Brooke et al 2014;Sneden et al 2014).…”

An update to the MARVEL data set and ExoMol line list for 12C2

“…Figure 1 gives an overview of the observed band systems for 12 C 2 with colour used to indicate those explicitly dealt with in this study. In response to the needs of astrophysics and other areas of physics, Yurchenko et al (2018b) computed a comprehensive line list for 12 C 2 as part of the ExoMol project (Tennyson & Yurchenko 2012), called the 8states line list. This line list was generated by variational solution of the nuclear Schrödinger equation for the states involved (Yurchenko et al 2016) and covers the band systems linking the lowest eight electronic states, namely the Swan, Phillips, Ballik-Ramsay, Duck, Bernath B and B' bands, and the singlet-triplet intercombination lines.…”