A collision-induced satellite in the Lyman Beta profile due to H-H   collisions
  We present a theoretical profile of the Lyman Beta line of atomic hydrogen perturbed by collisions with neutral hydrogen atoms and protons. We use a general unified theory in which the electric dipole moment varies during a collision. A collision-induced satellite appears on Lyman Beta, correlated to the B''\barB 1Sigma+u - X 1Sigma+g asymptotically forbidden transition of H_2. As a consequence, the appearance of the line wing between Lyman Alpha and Lyman Beta is shown to be sensitive to the relative abundance of hydrogen ions and neutral atoms, and thereby to provide a temperature diagnostic for stellar atmospheres and laboratory plasmas. 
N.F.Allard, J.Kielkopf, I.Drira and P.Schmelcher