function molecule_thin_emission, density, species
common molecular_data, moldata
; 
; Interpolate values in moldat.txt and read in by read_moldat.pro
;
; the abundances are specified here. 

emission = density              ; same structure as input density 
mean_molecular_weight = 2.3
abundance = [1., 1., 1.] 
emission[*] = abundance[species] * $
              interpol(moldata[species+1,*], moldata[0,*], density[*]/mean_molecular_weight,/spline)
return, emission
end