RFM Flags: Define spectral axis in GHz rather than cm-1

GHZ Flag

12OCT22

Enabled

Disabled

Restrictions
None

Notes
  1. GHz units are normally used in the microwave region. For this region it is also advised to use the VVW Flag or Van Vleck Weisskopf lineshape in the *SHP section.
  2. Internally the RFM always works in cm-1, so spectral ranges defined in GHz in the *SPC section are converted to cm-1 using the factor 1E7/VLIGHT (approximately 1/30), where VLIGHT, the speed of light, is defined in phycon_dat.f90. Conversely, the spectral axis (defined in header record#3 of the output spectral files), is converted back to GHz before being written to the file.
  3. .ils files (more commonly known as spectral response functions in the microwave) may be expressed in either cm-1 or GHz. If incompatible with the GHZ Flag, the appropriate conversion is made and a warning message sent to the rfm.log file
  4. .tab input/output files may be specified on GHz or cm-1 axes, the RFM handles the conversion automatically.
  5. All other spectral input data, e.g., in the *HIT, *XSC and *CIA sections, are always assumed to be in cm-1.

Bugs
[none reported]