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Dear Prof. Piquini,
I am sorry but I never received your files. Could you please try again?

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Hi,

In the context of TOPOND, PS does indeed label an atom for which a PSeudopotential is used. At some point of the output the coordinates of the PS atomic center are printed, which should allow for its identification.

Hope this helps,

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Dear Piquini,
thank you for your email. Is there any possibility to have a look at your input-output files? If you prefer you can send them to [email protected].

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Excellent, thank you for the quick feedback.

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Hi,

We have checked the implementation. The values printed in the output of the BETAVIB calculation for SHG and Pockels are expressed in atomic units and correspond to \( \frac{1}{2}{\boldsymbol{ \beta}} \). That is, the factor of \( \frac{2\pi}{V} \) seems to be missing to make them the d tensor. In other words, by multiplying the values in the output by \( \frac{2\pi}{V} \) you should get d.

Please, let me know if you think this makes sense based on the values you get for your system.

Sorry for the confusion.
Hope this helps,

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Dear leszec_malec,

You can bypass the error by using a functional parameterized for DFT-D3 (BJ), for example PBE, and then manually defining the dispersion parameters.

Please see the DFTD3 block below:

DFTD3
VERSION
4
FUNC
PBE
S6
1.0000
S8
1.6112
A1
0.0000
A2
7.3539
END

Best regards,

Lorenzo

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Formally, if finite temperature effects are to be included, the internal static energy E needs to be substituted with the free energy F in the definition of the Hessian. This is easier said than done. However, for the elastic tensor, we do have an implementation to compute free energy derivatives with respect to lattice strain (i.e. thermo-elasticity). See also:

https://www.mdpi.com/2075-163X/9/1/16

The elastic tensor is not defined for 0D systems, where you could just explore the "dynamical stability" in terms of the vibration frequencies.

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Hi,

Stability is a broad concept that can be interpreted and analyzed in many ways. One way to look at it is the following: checking whether or not the Hessian of second energy derivatives is positive-definite (all eigenvalues are positive) or not, i.e. if the structure is a local minimum of the potential energy surface (PES). Indeed if small structural perturbations produce an energy decrease rather than increase (that is if some of the eigenvalues are negative) the structure can not be considered "stable".

Two types of Hessian matrix can be considered, which correspond to two types of stability:

Hessian with respect to atomic displacements within a fixed cell for dynamical (phonon) stability. This corresponds to checking if all harmonic frequencies are positive.
Hessian with respect to lattice distortions for mechanical stability (so-called Born stability conditions). This corresponds to checking if all the eigenvalues of the elastic tensor are positive.

Hope this helps,

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Hi Chris,
I tested the same input with properties and it starts correctly, so the input deck itself seems fine. The issue may instead be that the launch script that is not pointing to the correct input file.

Without your fort.9 I cannot test the full input, but if you share a few details on your setup and how you launch the job, it may be easier to identify the problem.

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Dear Chhatra,

Unfortunately, I am not aware of a direct way to reduce the file size generated by the ORBITAL option in the properties module.

As a possible workaround, you might consider reducing the system size if feasible. Another option could be to post-process the output to extract only the relevant information before visualization.

I hope this helps.

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