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Voigt Profile Decomposition

What you are seeing: the Voigt absorption profile (orange) is the convolution of a Gaussian (cyan, thermal broadening) with a Lorentzian (green, natural / pressure broadening). The Gaussian dominates the core; the Lorentzian dominates the far wings.

Figure 1. Voigt vs constituents.
σ (Gauss)0.80
γ (Lorentz)0.40

WHAT TO TRY

  • Widen the Gaussian sigma (thermal broadening): the Voigt core fattens and rounds. Hotter gas broadens the Doppler core at line center.
  • Raise the Lorentzian gamma (natural and pressure broadening): the far wings lift while the core barely moves. The Lorentzian always wins in the wings, which is how a line shape reads out pressure.
  • Watch the convolution build: the shaded product of the sliding Gaussian against the Lorentzian, integrated, is the Voigt value at each shift. That is convolution shown geometrically.