Task 6: Small exercises for Diatomic molecules (can run on laptops including Windows) - Trovemaster/exocross GitHub Wiki

Download the NaH line list from http://exomol.com/data/molecules/NaH/23Na-1H/Rivlin/. On DiRAC, they can be found in /scratch/dp114/shared/NaH/
On Windows, download the Exocross executable xcross_dos.exe and the batch file run_exocross.bat from the github repository at https://github.com/Trovemaster/exocross and place into the same folder with the data. On Linux, one can obtain exocross.exe
Using a text editor create a ExoCross input file to compute emission cross sections for NaH (main isotopologue), T=1500 K and P=1 atm using the Voigt line profile assuming He and H2 as broadeners (0.85/0.15) with constant broadening parameters. The wavenumber grid is 0-25000 cm-1 and the grid size is 1 cm-1. An example is shown below (NaH_Voigt_1500K.inp).
```
Range 0.0  25000.0
Npoints 25001

Emission
pressure  1.0
Temperature 1500.0
mass 23

Voigt

species
  H2  gamma 0.0155 n 0.41 t0 298.0 ratio 0.82
  He  gamma 0.1070 n 0.77 t0 298.0 ratio 0.18
end

Output NaH_Voigt_emission_1500K_P1

States 23Na-1H__Rivlin.states
Transitions 23Na-1H__Rivlin.trans
```
On windows, modify the batch file run_exocross.bat to include the following line

xcross_dos.exe < NaH_Voigt_1500K.inp> NaH_Voigt_1500K.out

On Linux run

exocross.exe < NaH_Voigt_1500K.inp> NaH_Voigt_1500K.out

This will produce a new Stats file (.lifetime) with lifetimes written as the 5th columns, with which is copy of the .states.

Lifetimes can be computed using ExoMol line lists with using the following simple input file:
```
 lifetimes
 
 States 23Na-1H__Rivlin.states
 Transitions 23Na-1H__Rivlin.trans
```
An example of the cross sections of AlO can be found in /scratch/dp114/dc-yurc1/exocross/AlO. Use this example to produce cross sections for FeH and BeH see /scratch//dp114/shared/ExoMol, or any other diatomic from http://exomol.com/data/molecules/.