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

We are researching LiF and we are interested in creating a potential energy curve for the crystalline structure of LiF. From what we have already found out, a diatomic case is not described in an asymptotically correct way by any density functional but is described by MP2–MP4 (the internal energy with Coulomb energy subtracted goes to 0 at large distances).

In the manual, it is mentioned that CRYSTAL can compute MP2 for single points. However, when we launch it, the following error happens:

We tried both the parallel and the serial version, the error is the same. Actually, for the parallel version it starts to compute MP2 and then falls out.

What can be the issue?

LiF_MP2.pobtzvp_rev2_sp.out

LiF_MP2.pobtzvp_rev2_sp_parallel.out