Cross-sections access 2015

The absorption cross-sections σ (ω), expressed in cm² molecule^-1 , at a given wavenumber ω, are determined through the following expression: σ (ω)= ( ln [ I₀(ω) / I(ω) ] ) / n*l

– ln is the natural logarithm
– ω is the wavenumber (cm^-1)
– I0(ω) and I(ω) are the intensities at wavenumber ω , of the incident and transmitted radiation, respectively
– n is the number of absorbing molecules (molecule cm^-3)
– l is the optical path length (cm)