Kaltakm: Created page with "{{TAGDEF|DAMP_NEWTON|real number}} {{DEF|DAMP_NEWTON|0.8}} Description: Sets the damping factor applied to the RPA forces during Newton-step structure relaxation. ---- {{TAG|DAMP_NEWTON}} controls the step size of the Newton-step geometry update performed during [https://vasp.at/wiki/ACFDT/RPA_calculations Random Phase Approximation] (RPA) force calculations. The updated atomic positions are computed as: : '''x'''_new = '''x'''_current + DAMP_NEWTON..."

2026-03-17T14:46:16Z

Created page with "{{TAGDEF|DAMP_NEWTON|real number}} {{DEF|DAMP_NEWTON|0.8}} Description: Sets the damping factor applied to the RPA forces during Newton-step structure relaxation. ---- {{TAG|DAMP_NEWTON}} controls the step size of the Newton-step geometry update performed during [https://vasp.at/wiki/ACFDT/RPA_calculations Random Phase Approximation] (RPA) force calculations. The updated atomic positions are computed as: : '''x'''new = '''x'''current + DAMP_NEWTON..."

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{{TAGDEF|DAMP_NEWTON|real number}}
{{DEF|DAMP_NEWTON|0.8}}
Description: Sets the damping factor applied to the RPA forces during Newton-step structure relaxation.
----
{{TAG|DAMP_NEWTON}} controls the step size of the Newton-step geometry update performed during
[https://vasp.at/wiki/ACFDT/RPA_calculations Random Phase Approximation] (RPA) force calculations. The updated atomic positions are computed as:

: '''x'''new = '''x'''current + DAMP_NEWTON × '''H'''−1 · '''F'''RPA

where '''H'''−1 is the inverse of the DFT Hessian (computed during the RPA force
calculation) and '''F'''RPA are the RPA forces.{{cite|ramberger:prl:118}} The resulting updated positions are written
to the {{TAG|CONTCAR}} file (provided {{TAG|NSW}}=0). Iterating this procedure—by copying
{{TAG|CONTCAR}} to {{TAG|POSCAR}} and re-running—should converge the system toward its
ground-state structure.
{{Available|6.1.0}}

==Available options==

=== {{TAG|DAMP_NEWTON}}=1.0: No damping ===
: No damping is applied; the full Newton step is taken. This is appropriate when the RPA forces
are well-behaved and the optimization is proceeding stably.

=== {{TAG|DAMP_NEWTON}}=0.8: Default damping ===
: The default value. A mild damping factor of 0.8 is applied to the Newton step, providing a
small degree of stabilization during the iterative relaxation without significantly slowing
convergence.

=== {{TAG|DAMP_NEWTON}}<0.8: Strong damping ===
: Use smaller values if numerical instabilities are observed during the RPA relaxation.
{{NB| warning | Excessively small values will slow convergence considerably. Reduce {{TAG|DAMP_NEWTON}}
only when large or erratic RPA forces are encountered.|:}}

== Related tags and articles ==
{{TAG|CONTCAR}},
{{TAG|POSCAR}},
{{TAG|NSW}},
{{TAG|IBRION}}
{{sc|DAMP_NEWTON|HowTo|Workflows that use RPA force relaxation}}

== References ==
<references/>

DAMP NEWTON - Revision history