  Calculations of the opacity of hot, dense matter require models for plasma
line broadening. However, the most general theories are too complex to
calculate directly and some approximation is inevitably required. The most
widely-used approaches focus on the line centre, where a Lorentzian shape is
obtained. Here, we demonstrate that in the opposite limit, far from the line
centre, the opacity can be expressed in terms of second-order transitions, such
as electron-photon and two-photon processes. We suggest that this insight could
form the basis for a new approach to improve calculations of opacity in hot,
dense matter. Preliminary calculations suggest that this approach could yield
increased opacity away from absorption lines.
