Force Field Dialog Box

Specify a force field for the current task, and optional custom charges.

To open this dialog box, click the Force Field button in any panel that has it.

  • Features
  • Additional Resources

Force Field Dialog Box Features

Note

The force fields available in the dialog box depend on the application from which it is opened. This topic lists all available force fields.

Force field option menu

Choose the force field for the current task. The choices are OPLS_2005, OPLS4, OPLS5, and MLFF and are dependent on having the appropriate license. The default is OPLS4 if it is available, otherwise it is OPLS_2005, unless you set the default in the Force Field settings section of the Preferences Panel.

Use customized version option

Use your customized version of the OPLS4 or OPLS5 force field, rather than the standard version in the distribution. Only available when you choose OPLS4 or OPLS5 from the Force field option menu and you have the appropriate license. This option is set by default to the value of the Use custom parameters by default option in the Preferences panel, under Jobs - Force field, when the current panel is opened. The default directory for the customized version can also be specified as a preference, in the same location.

If the customized version is missing or invalid, the text of this option turns orange and an orange warning icon is displayed to the right, with a tooltip about the problem.

Parameter set button

Select the set of custom parameters for the OPLS4 or OPLS5 force field. Opens the Set Custom Parameters Location Dialog Box. Only available when you choose OPLS4 or OPLS5 from the Force field option menu and you have the appropriate license.

OPLS5 Metals force field options button ()

Click this button to open a popdown pane with options for enabling the OPLS5 Metals force field. This button is only displayed when OPLS5 is selected as the force field.

Enable OPLS5 Metals force field (beta) option

Select this option to use the OPLS5 Metals force field for systems containing supported metals. The supported metals are Ca, Fe, Ir, Mg, Pt, Zn. The OPLS5 Metals force field is significantly slower than the standard OPLS5 force field. Only available after the input structures have been analyzed successfully and the criteria for using the OPLS5 Metals force field has been met.

Analyze Structures button

Click this button to analyze the input structures and determine whether the OPLS5 Metals force field can be used. The analysis checks that the structures contain supported metal elements and that the coordination environment around each metal center is compatible with the OPLS5 Metals force field. If the structures meet the criteria, the Enable OPLS5 Metals force field (beta) option becomes available. If the input structures change after the analysis, the analysis must be repeated.

Custom Charges button

Specify custom charges for the force field, taken from an atom-level property. Opens the Custom Atom Charges Dialog Box.

When you choose MLFF as the force field, you can select the machine learning force field model to use, for some workflows including a Custom model that you have trained yourself using the MLFF Fine-tuning Panel. See Machine Learning Force Fields.

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