Molecular Line Opacity of LiCl in the Mid‐Infrared Spectra of Brown Dwarfs

We present a complete line list for the X 1Sigma+ electronic ground state ofLiCl computed using fully quantum-mechanical techniques. This list includestransition energies and oscillator strengths in the spectral region0.3-39,640.7 cm-1 for all allowed rovibrational transitions in absorptionwithin the electronic ground state. The calculations were performed using anaccurate hybrid potential constructed from a spectral inversion fit ofexperimental data and from recent multi-reference single- and double-excitationconfiguration interaction calculations. The line list was incorporated into thestellar atmosphere code PHOENIX to compute spectra for a range of young to oldT dwarf models. The possibility of observing a signature of LiCl in absorptionnear 15.8 microns is addressed and the proposal to use this feature to estimatethe total lithium elemental abundance for these cool objects is discussed.Comment: 8 pages, 2 figures, 1 table. Accepted for publication in ApJ 613, Sept. 20 200