Please not I do not maintain this code any longer, nor do I have access to the optics_5.4.1 code. If you do not already have that code then it is unlikely you can use this tool.
I recommend the sl3me tool which does the same but is supported: https://github.com/ldwillia/SL3ME
The SLME method is outlined in the paper of Yu and Zunger, PRL, 108,068701
The following is a collection of some of the tools you need to calculate the SLME.
- Run a normal VASP calculation using INCAR.ele and dense,
$$\Gamma$$ -point centred k-mesh. - Obtain the minimum band gap [we call this E_g^fund]
- Copy IBZKPTS to KPOINTS
- Run a VASP calculation using INCAR.opt [Produces OPTIC]
- Copy the OPTCTR.eps file to OPTCTR
- Run the optics_5.4.1 [Produces EPS]
- Run the script make_diel.py [Produces DIEL]
- Copy the OPTCTR.trans to OPTCTR
- Run
optics_5.4.1 > Transitions.dat[Returns the value of E_g^allowed] - Now run the SLME code:
python calc_slme.py DIEL E_g^fund E_g^allowed 0.1
NB the optics processing is available from the VASP site