Single-Point Calculations

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.

Hello Prof. Erba,

Thank you for providing the reference and relevant pages. This is very useful.

Best,
Danny

Your response is incredibly valuable—thank you so much.I suspect that the DIIS/Anderson extrapolation might have 'hit' a local minimum, so the density guess in iteration 8 happened to yield a total energy extremely close to that of the previous step, resulting in a very small ΔE.
CYC 0 ETOT(AU) -8.456120523718E+03 DETOT -8.46E+03 tst 0.00E+00 PX 1.00E+00
CYC 1 ETOT(AU) -8.390242659622E+03 DETOT 6.59E+01 tst 0.00E+00 PX 1.00E+00
CYC 2 ETOT(AU) -8.391027170997E+03 DETOT -7.85E-01 tst 3.34E-03 PX 1.13E-01
CYC 3 ETOT(AU) -8.391734802465E+03 DETOT -7.08E-01 tst 2.44E-03 PX 1.02E-01
CYC 4 ETOT(AU) -8.392064543836E+03 DETOT -3.30E-01 tst 8.38E-04 PX 4.49E-02
CYC 5 ETOT(AU) -8.392086825687E+03 DETOT -2.23E-02 tst 1.24E-04 PX 1.72E-02
CYC 6 ETOT(AU) -8.392095974656E+03 DETOT -9.15E-03 tst 2.86E-05 PX 9.66E-03
CYC 7 ETOT(AU) -8.392097542826E+03 DETOT -1.57E-03 tst 3.85E-06 PX 4.81E-03
CYC 8 ETOT(AU) -8.392097541980E+03 DETOT 8.46E-07 tst 5.41E-06 PX 3.18E-03
CYC 9 ETOT(AU) -8.392098065539E+03 DETOT -5.24E-04 tst 4.69E-06 PX 3.18E-03
While this DETOT value satisfies the default energy convergence criterion, the corresponding values suggest that the electron density had not yet fully stabilized. This aligns well with your suggestion that tightening the convergence threshold would lead to a more reliable result.
Thank you again for your guidance.

Hi Alessandro and Giacomo,

Thank you for the clear and helpful explanations!

I tried running the calculation with 32 cores, and it indeed helped with memory management. I’ll continue experimenting to optimize performance. Really appreciate your guidance and the references!

Dear Eleonora and Aleks,

Thank you so much for the detailed explanation and for sharing the corrected input/output file. That really clarified the issue. I tried your suggested settings with FMIXING and SPINLOCK adjustments, and the geometry optimization is running well with no errors. Have a nice day!

Best,
Aparajita

Hey,

Thank you. It works now. This Forum is a great idea!

job314 Good point! About the shrinking factor: the anisotropic shrinking factor in CRYSTAL does not work properly for those calculations where the symmetry of the system may change (for instance in frequency calculations, FREQCALC, where displaced nuclear configurations are explored, or elastic calculations, ELASTCON, where the lattice is strained, etc.). So in general, I personally tend to avoid using an anisotropic shrinking factor.

However, for symmetry-preserving calculations (such as SCF, OPTGEOM, EOS) the use of an anisotropic shrinking factor should be fine.