RFM Driver Table Sections

*SHP Section: Molecular Lineshapes


Secondary Section - activated by SHP Flag.

User-defined (ie non-Voigt) spectral line shapes.

Multiple records, arbitrary order
Record structure: SHPNAM GAS(1) GAS(2) ... GAS(N)
SHPNAM C*3 Lineshape to be used
GAS C*7 Molecule to which lineshape is applied, or '*'
Allowed values for SHPNAM
VOI Voigt Lineshape
LOR Lorentz Lineshape
DOP Doppler Lineshape
VVW or VAN Van Vleck Weisskopf Lineshape
CHI Voigt plus Chi-factor

  1. Only the first 3 characters of SHPNAM are tested so, for example, LORENTZ can be used for LOR.
  2. An asterisk (*) may be substituted for GAS once in this section, in which case it is taken to represent all required gases not explicitly allocated other shapes.
  3. If no asterisk is present, all absorbers must be explicitly allocated a lineshape
    RFM v4.33 onwards: any absorbers not explicitly assigned a shape will use the Voigt lineshape (subject to CHI modifications for CO2)
  4. Currently the CHI shape can only be used with CO2 (represents sub-Lorentzian wings of CO2) - see CHI flag for a shorter way of invoking this. The RFM uses the model of Cousin et al (1985).
  5. The VVW lineshape specified here is an explicit calculation of the Van Vleck Weisskopf lineshape, i.e., the Lorentz lineshape with low-wavenumber correction terms (recommended for calculations in microwave region).
  6. The VVW Flag can be used for applying the same correction to all lineshapes, i.e. VVW lineshape specified in this section is equivalent to LOR lineshape + VVW Flag.
  7. If both the VVW Flag and VVW lineshape are specified, a warning is generated but the VVW correction is ignored for lines already generated with the VVW lineshape.

     Chi-factor  CO2    ! Use CO2 sub-Lorentzian wings 
     LORENTZ  H2O CH4   ! Use Lorentz shape for H2O and CH4
     LORENTZ  N2O       ! Also N2O
     VOI         *      ! Use Voigt shape for all other absorbers
     DOPP CO            ! Doppler shape for CO

[none reported]