Want to know about some options in md parameter file

User discussions
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1

GROMACS version: 2018.1
GROMACS modification: No

Can anyone please tell me what the following options (in bold) for QMMM calculatuions in the .mdp file are …

CAS space options
CASorbitals =
CASelectrons =
SAon =
SAoff =
SAsteps =

Thank you.

2

This is old and currently unsupported code.
CAS parameters are referring to the CASSCF method for exploring excited states:
https://gaussian.com/cas/