engleski

Lithium, sodium, and potassium resonance lines pressure broadened by helium atoms

The resonance lines of the alkali-metal atoms, broadened by collisions with helium atoms, are prominent features in the spectra of brown dwarfs. We carried out calculations of the emission and absorption spectra in the far-red and blue wings of the first resonant doublets of Li, Na, and K perturbed by He atoms, for temperatures from 500 to 3000 K. For our calculation we used carefully constructed electronic adiabatic potential energy curves and electronic transition dipole moments of Li- He, Na-He and K-He molecules. In the computation of the emission and absorption coefficients, we used the fully quantum- mechanical calculation, based on the Fourier grid Hamiltonian method. The obtained absorption and emission spectra are compared with previous theoretical calculations.

molecular data - line: profiles - stars: brown dwarfs

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