Unexpectedly cannot get the geometry after optimization: KEYWORD EXTPRT NOT ALLOWED

esmuigors

Dear CRYSTAL support and others,

I am new to CRYSTAL, hence the error is probably on my side.

I am trying to perform a geometry optimization of a molecular crystal and then use it to compute the dielectric susceptibilities. If I understand it correctly, I need to use the keyword EXTPRT within the OPTGEOM section to export the optimized geometry and get a fort.34 file, which I then have to use in my next calculation with EXTERNAL keyword for the geometry.

However, the run fails with an error message:

ERROR **** CONOPT_ **** KEYWORD EXTPRT      NOT ALLOWED
forrtl: error (78): process killed (SIGTERM)

If I remove the EXTPRT keyword, the optimization runs just fine (at least with some of the functionals)! But I cannot get the geometry out of the .OUT file. I tried using the cell parameters I got after "CRYSTALLOGRAPHIC CELL" and run an elastic constant calculation; however, it failed with "WARNING!! FORCE 9 AT CENTRAL POINT IS GREATER THAN 10^-4. OPTIMIZE THE STRUCTURE AND RE-RUN" (there were multiple such messages for multiple force vectors) and the error

 ERROR **** BFGS_ **** PXK TOO SMALL

So I am now at loss trying to get the geometry out of my optimization. Can anyone help please?

Please find inputs for the jobs attached.
CS2_normalP_r2SCANh.pob_tzvp_rev2_opt_withEXTPRT.out CS2_normalP_r2SCANh.pob_tzvp_rev2_opt_withoutEXTPRT.out CS2_r2SCANh.pob_tzvp_rev2_elconst_manualCOORDS.out

GiacomoAmbrogio

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.