Investigate the Impact of Pressure and Strain on Formation Enthalpy in elastool.

[hongyi-zhao]

Hello elastool developer,

I have specific questions regarding the influence of pressure (a) and strain (b) on the formation enthalpy. I'm not sure whether elastool has the feature for such calculation and analysis.

Thank you very much for your tips and hints.

Best regards,
Zhao

[gmp007]

Hi Zhao, It is not currently implemented in ElasTool, but it is pretty straightforward if it is a feature you want. You'll need sizeable stress/strain to do a proper derivative.

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On Thu, Apr 11, 2024 at 10:13 AM hongyi-zhao ***@***.***> wrote: Hello elastool developer, I have specific questions regarding the influence of pressure (a) and strain (b) on the formation enthalpy. I'm not sure whether elastool has the feature for such calculation and analysis. Thank you very much for your tips and hints. Best regards, Zhao — Reply to this email directly, view it on GitHub <#7>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEYH5LHCESEORCSMLRQC7XTY42K7PAVCNFSM6AAAAABGCMP2ZKVHI2DSMVQWIX3LMV43ASLTON2WKOZSGIZTOOBTGA4DINI> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[hongyi-zhao]

Hi @gmp007,

Thank you for your comments. Do you agree with the following formula to calculate the enthalpy of formation?

[gmp007]

That looks correct to me. Think about formation enthalpy as formation energy at 0 K. Broadly defined, formation enthalpy is temperature-dependent.

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On Fri, Apr 12, 2024 at 10:16 AM hongyi-zhao ***@***.***> wrote: Hi @gmp007 <https://github.com/gmp007>, Thank you for your comments. Do you agree with the following formula to calculate the enthalpy of formation? <https://mattermodeling.stackexchange.com/questions/4260/how-to-calculate-the-enthalpy-of-formation> image.png (view on web) <https://github.com/zhongliliu/elastool/assets/11155854/0274ff85-f866-4069-af1c-6cf9c8712426> — Reply to this email directly, view it on GitHub <#7 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEYH5LBKX45FFJCW6PNQ3B3Y47UCHAVCNFSM6AAAAABGCMP2ZKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDANJRHA2DOOJZGY> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[hongyi-zhao]

Broadly defined, formation enthalpy is temperature-dependent.

In general, however, this form of temperature-dependent should be complex and difficult to calculate, at least within the framework of the DFT.

[gmp007]

Yes, no temperature in DFT, but one can incorporate temperature in various forms, e.g., QHA.

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On Fri, Apr 12, 2024 at 10:49 AM hongyi-zhao ***@***.***> wrote: Broadly defined, formation enthalpy is temperature-dependent. In general, however, this form of temperature-dependent should be complex and difficult to calculate, at least within the framework of the DFT. — Reply to this email directly, view it on GitHub <#7 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEYH5LFNDVKTSL2QKAW5BJ3Y47X67AVCNFSM6AAAAABGCMP2ZKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDANJRHEYDOMZUHE> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[hongyi-zhao]

About the QHA, I recently noticed the question asked here with the topic "Debye temperature calculation formula in the QuasiharmonicDebyeApprox class":

As for the above question, I have tried to think and understand it, but finally I still do not understand how the circle 1 and circle 2 shown in the above figure correspond. I'm not sure if you'd be able to give some hints and ideas on this question.

[gmp007]

Hi Zhongliliu, I cannot comment on whether it is correct or not. One has to fully derive it to be sure. QHA is just adding the vibrational free energy of the nuclei to the zero-temperature free energy from DFT. I am not sure what you need this formula for to start with. If you need Debye temperature, ElasTool provides it using the sound velocity, which corresponds to the acoustic phonon in terms of vibrational properties.

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On Fri, Apr 12, 2024 at 9:42 PM hongyi-zhao ***@***.***> wrote: About the QHA, I recently noticed the question asked here <materialsproject/pymatgen#3608>: image.png (view on web) <https://github.com/zhongliliu/elastool/assets/11155854/67a8bc6f-3821-4021-b499-db6144422fef> As for the above question, I have tried to think and understand it, but finally I still do not understand how the circle 1 and circle 2 shown in the above figure correspond. I'm not sure if you'd be able to give some hints and ideas on this question. — Reply to this email directly, view it on GitHub <#7 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEYH5LDPIZ2ZBWUDMNWKKN3Y5CEPTAVCNFSM6AAAAABGCMP2ZKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDANJSHEZDCOJTG4> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[zhongliliu]

Hi Chinedu, Elastool does not use QHA. The formation enthalpy can be obtained using other code, such as PhaseGO which deals with QHA. Zhongli At 2024-04-13 10:00:28, "gmp007" ***@***.***> wrote: Hi Zhongliliu, I cannot comment on whether it is correct or not. One has to fully derive it to be sure. QHA is just adding the vibrational free energy of the nuclei to the zero-temperature free energy from DFT. I am not sure what you need this formula for to start with. If you need Debye temperature, ElasTool provides it using the sound velocity, which corresponds to the acoustic phonon in terms of vibrational properties.

On Fri, Apr 12, 2024 at 9:42 PM hongyi-zhao ***@***.***> wrote: About the QHA, I recently noticed the question asked here <materialsproject/pymatgen#3608>: image.png (view on web) <https://github.com/zhongliliu/elastool/assets/11155854/67a8bc6f-3821-4021-b499-db6144422fef> As for the above question, I have tried to think and understand it, but finally I still do not understand how the circle 1 and circle 2 shown in the above figure correspond. I'm not sure if you'd be able to give some hints and ideas on this question. — Reply to this email directly, view it on GitHub <#7 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AEYH5LDPIZ2ZBWUDMNWKKN3Y5CEPTAVCNFSM6AAAAABGCMP2ZKVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDANJSHEZDCOJTG4> . You are receiving this because you were mentioned.Message ID: ***@***.***>

— Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[gmp007]

I want to believe this is taken care of. I am going to close this thread. Let us know if you need further assistance.