(prior to RFM v5) The file used is not the original HITRAN ASCII data but an RFM-specific
version (to allow fast, random access). This binary version can be created by
RFM v5: the original HITRAN .par file (160 character
text records) can also be used directly, although this will be slower since
every record has to be read.
The *HIT section is optional if all 'line'
molecules are represented
by Look-Up Tables instead, but since you are
likely to have only one version of the HITRAN data then you might as well
keep the *HIT section in the driver tables anyway.