RFM Flags

QAD Flag: Quadratic Interpolation of Line Wings


Use simple quadratic interpolation to model line wings on fine grid.

Use inverse quadratic (Lorentzian shape) interpolation to model line wings on fine grid


  1. The main use of this flag is to investigate whether the form of polynomial used to interpolate wide-mesh calculations to the fine grid significantly affects the results. The order of polynomial is hard-wired by the dimension 3 in arrays ABSWID, CNTWID (see Memory Size) and not something that is easily altered, so inverting it is about the only option.
  2. A second use is that the RFM may flip from inverse quadratic to quadratic for a small change in input parameters, giving significantly different spectra. The clue is that the difference between two spectra has a sinusoidal shape in a 1 cm-1 internval with a zero-crossing at 0.5 cm-1. This flag forces quadratic throughout which, although not as accurate, at least enforces consistency.

[none reported]