Impact broadening of alkali lines in brown dwarfs

International audienceSpectral line widths of the light alkalies are presented for conditions prevailing in brown dwarf atmospheres. A unified line shape theory and a set of pseudopotentials are used to compute widths of Li, Na, and K resonance lines perturbed by He and H2. While limited available experimental data confirm the trends found in the theoretical values reported here, they suggest that improved potentials are needed