Hi,
I'm trying to compute the elastic constants of silicon using the CHGNet model via ForceFieldRelaxMaker and the ElasticMaker from the atomate2 workflow.
Setup:
Structure: Silicon (mp-149)
Model: CHGNet
Workflow: ElasticMaker with ForceFieldRelaxMaker as the relaxer
Relaxation: fmax = 1e-5
No static DFT steps, fully force-field based
Issue:
The computed elastic constants are highly unphysical. Specifically, the diagonal components of the elastic tensor (C11, C22, C33) are ~ of order of -(1e6), while the off-diagonal and shear terms seem reasonable. I assumed the units are in GPa, but given the magnitude, it’s possible something else is wrong.
Questions:
Are the units of the elastic constants (from CHGNet or ForceFieldElasticMaker) in GPa, or something else (e.g., eV/ų)? What could be the reason for this unphysical value of elastic constants ?
I can share my code snippet if needed.
Thanks for your time!
Best regards,
Suhas Adiga
Hi,
I'm trying to compute the elastic constants of silicon using the CHGNet model via ForceFieldRelaxMaker and the ElasticMaker from the atomate2 workflow.
Setup:
Structure: Silicon (mp-149)
Model: CHGNet
Workflow: ElasticMaker with ForceFieldRelaxMaker as the relaxer
Relaxation: fmax = 1e-5
No static DFT steps, fully force-field based
Issue:
The computed elastic constants are highly unphysical. Specifically, the diagonal components of the elastic tensor (C11, C22, C33) are ~ of order of -(1e6), while the off-diagonal and shear terms seem reasonable. I assumed the units are in GPa, but given the magnitude, it’s possible something else is wrong.
Questions:
Are the units of the elastic constants (from CHGNet or ForceFieldElasticMaker) in GPa, or something else (e.g., eV/ų)? What could be the reason for this unphysical value of elastic constants ?
I can share my code snippet if needed.
Thanks for your time!
Best regards,
Suhas Adiga