EDIFF: Difference between revisions

Revision as of 10:56, 2 February 2022

EDIFF = [real]
Default: EDIFF = $10^{-4}$

Description: EDIFF specifies the global break condition for the electronic SC-loop. EDIFF is specified in units of eV.

The relaxation of the electronic degrees of freedom stops if the total (free) energy change and the band-structure-energy change ('change of eigenvalues') between two steps are both smaller than EDIFF (in eV). For EDIFF=0, strictly NELM electronic self-consistency steps will be performed.

Mind: In most cases, the convergence speed is exponential, so often, the cost for the few additional iterations is small. For high precision calculations, we recommend decreasing EDIFF to 1E-6. For finite difference calculations (e.g. phonons), even EDIFF = 1E-7 might be required in order to obtain very accurate results.

Related Tags and Sections

EDIFFG

Examples that use this tag

Contents

@@ Line 1: / Line 1: @@
 {{TAGDEF|EDIFF|[real]|<math>10^{-4}</math>}}
-Description: {{TAG|EDIFF}} specifies the global break condition for the electronic SC-loop. EDIFF is specified in units of eV.
+Description: {{TAG|EDIFF}} specifies the global break condition for the electronic SC-loop. {{TAG|EDIFF}} is specified in units of eV.
 ----
-The relaxation of the electronic degrees of freedom will be stopped if the total (free) energy change and the band structure energy change ('change of eigenvalues') between two steps are both smaller than {{TAG|EDIFF}} (in eV). For {{TAG|EDIFF}}=0, strictly {{TAG|NELM}} electronic SC-steps will be performed.
+The relaxation of the electronic degrees of freedom stops if the total (free) energy change and the band-structure-energy change ('change of eigenvalues') between two steps are both smaller than {{TAG|EDIFF}} (in eV). For {{TAG|EDIFF}}=0, strictly {{TAG|NELM}} electronic self-consistency steps will be performed.
-'''Mind''': In most cases the convergence speed is exponential, so often the cost for the few additional iterations is small. For high precision calculations, we recommend to decrease {{TAG|EDIFF}} to 1E-6. For finite difference calculations (e.g. phonons), even {{TAG|EDIFF}} = 1E-7 might be required in order to obtain very accurate results.
+{{NB|mind|In most cases, the convergence speed is exponential, so often, the cost for the few additional iterations is small. For high precision calculations, we recommend decreasing {{TAG|EDIFF}} to 1E-6. For finite difference calculations (e.g. phonons), even {{TAG|EDIFF}} {{=}} 1E-7 might be required in order to obtain very accurate results. }}
 == Related Tags and Sections ==