ABSTRACT
The Doppler half-intensity width of an atomic spectral line of wavelength λ or frequency ν is given at thermal equilibrium by Δ λ L λ = Δ ν L ν = 2 √ 2 R ℓ n 2 c √ T M = 7.16 × 10 − 7 √ T M https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203742433/53e9912e-dfc3-42b1-91b1-4eaf447a0f76/content/eq123.tif"/>
