ML LHEAT: Difference between revisions
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Description: This flag specifies whether the heat flux is calculated or not in the machine learning force field method. | Description: This flag specifies whether the heat flux is calculated or not in the machine learning force field method. | ||
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The heat flux within machine learning force fields can is decomposed into atomic contributions written as | |||
<math> | |||
\mathbf{q}(t) = \sum\limits_{i=1}^{N_{a}} \frac{d}{dt} \left( \mathbf{r}_{i} E_{i} \right), | |||
</math> | |||
<math> | |||
E_{i}=\frac{m_{i} \left|\mathbf{v}_{i} \right|^{2}}{2} + U_{i} | |||
</math> | |||
where <math>\mathbf{r}_{i}</math>, <math>\mathbf{v}_{i}</math> and <math>E_{i}</math> denote the position vector, velocity and energy of atom <math>i</math>, respectively. | |||
The thermal conductivity at temperature <math>T</math> in the Green-Kubo formalism is calculated from the correlation of the heat flux <math>\mathbf{q}</math> as | The thermal conductivity at temperature <math>T</math> in the Green-Kubo formalism is calculated from the correlation of the heat flux <math>\mathbf{q}</math> as | ||
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\kappa = \frac{1}{3Vk_{b}T^{2}} \int\limits_{0}^{\infty} \langle \mathbf{q}(t) \cdot \mathbf{q}(0) \rangle dt, | \kappa = \frac{1}{3Vk_{b}T^{2}} \int\limits_{0}^{\infty} \langle \mathbf{q}(t) \cdot \mathbf{q}(0) \rangle dt, | ||
</math> | </math> | ||
where <math>V</math> and <math>k_{b}</math> denotes the volume of the system and the Boltzmann constant, respectively. | where <math>V</math> and <math>k_{b}</math> denotes the volume of the system and the Boltzmann constant, respectively. | ||
Revision as of 07:44, 9 June 2021
ML_FF_LHEAT_MB = [logical]
Default: ML_FF_LHEAT_MB = .FALSE.
Description: This flag specifies whether the heat flux is calculated or not in the machine learning force field method.
The heat flux within machine learning force fields can is decomposed into atomic contributions written as
where , and denote the position vector, velocity and energy of atom , respectively.
The thermal conductivity at temperature in the Green-Kubo formalism is calculated from the correlation of the heat flux as
where and denotes the volume of the system and the Boltzmann constant, respectively.
The heat flux is written to the file ML_HEAT.