Hi esmuigors,

When you run a geometry optimization (within the OPTGEOM block), CRYSTAL will always produce a fort.34 file (that contains the optimized structure and can be used in a subsequent calculation with the EXTERNAL keyword).
If you don’t see it after the run, a common cause is that it wasn’t copied back by the script used to manage scratch directories for the execution as the runCRY script provided with the code.

As for the error that you get, the issue is that EXTPRT should be placed outside the OPTGEOM block, as in this input.d12 example.

If you prefer, you can also extract the optimized geometry manually from the .out file. However, note that you must take both the final cell parameters (and angles, if present) and the final fractional atomic coordinates from the “FINAL OPTIMIZED GEOMETRY” section (those in the primitive cell), using only updated cell parameters without matching coordinates will lead to inconsistencies and errors like the ones you saw.

Let me know if you manage to get the optimized structure.

Hi,

The MP2 option is no longer supported in recent versions of the CRYSTAl program. If you are interested in a periodic MP2 calculation, my suggestion is to contact Lorenzo Maschio ([email protected]) and Denis Usvyat ([email protected]) directly, who may provide guidance in the use of the CRYSCOR program.