Hi everyone,
I’m running a QM/MM job with ChemShell 3.7 and ORCA on a system that contains 50 identical linear organic chains (C, H, O only) parameterised with GAFF.
The workflow is: build and equilibrate the system in GROMACS, take one snapshot, convert the GROMACS topology to AMBER format with ParmEd, set up the QM/MM regions in ChemShell, and submit the job.
The run always stops before ORCA is launched and prints the error message below:
I’ve checked every section of the generated
prmtop that uses the FORMAT(3E24.16) descriptor; they looks identical to files produced directly by AmberTools, and a recursive grep finds no other instance of that string.
Has anyone seen this message before? Does it point to ChemShell’s prmtop parser choking on a specific %FLAG, or could it be a hidden line-ending or encoding issue? Any advice or examples of working ParmEd-generated topologies with ChemShell+ORCA would be greatly appreciated.