1. Add to your .bashrc (in /home/) or execute

   export PATH=${PATH}:/scratch/dp114/shared/bin/

1. In /scratch/dp114/ crete a directory CO.
2. Copy the CO line list (.trans, .states and .pf files) from http://exomol.com/data/molecules/CO/12C-16O/Li2015/ to the directory CO using wget

wget wget http://exomol.com/db/CO/12C-16O/Li2015/12C-16O__Li2015.trans.bz

wget wget http://exomol.com/db/CO/12C-16O/Li2015/12C-16O__Li2015.states.bz

wget wget http://exomol.com/db/CO/12C-16O/Li2015/12C-16O__Li2015.pf.bz

3. Unpack the .bz2 files:

   bzip2 -d *.bz2

4. Create an input text file (text in brackets is for comments and can be omitted) as follows

   temperature 2000.0 (K) Range 0 20000 (cm-1) Npoints 200001 (0.1 step)

   absorption Doppler mass 28 (16+12 in Dalton)

   States 12C-16O__Li2015.states Transitions 12C-16O__Li2015.trans

   output CO_Doppler_2000K (any name)

This input file is to compute absorption CO cross sections for T = 2000 K on a grid of 0.1 cm-1 using the Doppler line profile.

5. Compute the Doppler by execute the command

exocross.exe <CO_Doppler.inp >CO_Doppler.out

This should produce a text file with cross sections in the following two-column format

   0.00000000E+000  2.94367130E-026
   2.00000000E+001  2.40232268E-024
   4.00000000E+001  2.00324058E-023
   6.00000000E+001  5.63337556E-023
   8.00000000E+001  1.00047217E-022
   1.00000000E+002  1.32660357E-022

6. It can be visualised, e.g., using xmgrace:

xmgrace CO_Doppler_2000K.xsec

See also the ExoMol cross-sections App http://exomol.com/data/molecules/CO/12C-16O/xsec-Li2015/ and the ExoMol Atlas https://arxiv.org/pdf/1805.03711.pdf

This exercise can be checked in /scratch/dp114/dc-yurc1/exocross/CO.