SCALEE: Difference between revisions
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{{TAGDEF|SCALEE|[real]|1}} | {{TAGDEF|SCALEE|[real]|1}} | ||
Description: This tag specifies the scaling of the energies and forces. | Description: This tag specifies the scaling constant of the energies and forces. | ||
---- | ---- | ||
In thermodynamic integration the free energy difference between two systems is defined as | |||
<math> \Delta F = \int\limits_{0}^{1} d\lambda \langle U_{1} - U_{0} \rangle </math> | |||
where | |||
For thermodynamic integration this parameter controls the coupling parameter <math>\lambda</math>. | For thermodynamic integration this parameter controls the coupling parameter <math>\lambda</math>. | ||
Revision as of 08:59, 31 March 2020
SCALEE = [real]
Default: SCALEE = 1
Description: This tag specifies the scaling constant of the energies and forces.
In thermodynamic integration the free energy difference between two systems is defined as
[math]\displaystyle{ \Delta F = \int\limits_{0}^{1} d\lambda \langle U_{1} - U_{0} \rangle }[/math]
where
For thermodynamic integration this parameter controls the coupling parameter [math]\displaystyle{ \lambda }[/math].
This parameter is only used if SCALEE[math]\displaystyle{ \ne }[/math]1.
Usually the thermodynamic integration is carried out from the ideal gas to the liquid state.
If the file DYNMATFULL exists in the calculation directory (from a previous calculation using PHON_NSTRUCT=-1) and SCALEE[math]\displaystyle{ \ne }[/math]1, the second order Hessian matrix is added to the force and thermodynamic integration from a harmonic model to a fully interacting system is carried out. Here the Hamiltonian for a certain integration point along the thermodynamic integration pathway is given as
[math]\displaystyle{ H_{\lambda} = (1-\lambda) H_{\mathrm{harmonic}} + \lambda H_{\mathrm{ab initio}}. }[/math]
Related Tags and Sections
VCAIMAGES, IMAGES, NCORE IN IMAGE1, PHON_NSTRUCT