Molecular modelers often encounter the challenge of efficiently optimizing molecular geometries while maintaining control over specific aspects of their structures. Whether you’re designing novel compounds or refining pre-existing structures, interactive minimization tools can become invaluable assets. SAMSON, the integrative molecular design platform, offers an intuitive and comprehensive approach to this task with its interactive minimization capabilities.
What is Interactive Minimization?
Interactive minimization allows users to refine molecular geometries while simultaneously interacting with their structures. Instead of relying on purely automated workflows, SAMSON enables you to actively participate in the optimization process and tailor results to meet specific scientific goals.
In SAMSON, the minimization process employs the Universal Force Field (UFF), a versatile and widely-used force field tailored to ensure fast and reliable results. This allows users to focus on designing better models while the platform handles geometry optimizations efficiently.
How to Perform Interactive Minimization?
Getting started with interactive minimization in SAMSON is simple:
- Begin by selecting
Edit > Minimizefrom the menu or use the shortcut key Z to kickstart the process. - Once active, the minimizer optimizes the geometry of all molecules in the active document by default.
- You can further modify minimizer options in the Minimize section of the Preferences panel to adapt to specific needs.

Fine-Tuning Minimization – Targeting Single Molecules
Among the standout interactive minimization features in SAMSON is its ability to selectively work on specific molecules. This avoids unnecessary alterations to other molecules in the document.
Follow these steps to minimize a single molecule:
- Uncheck the Include all atoms in the document option located in Interface > Preferences > Editors > Minimize.
- Use the Selecting tool to highlight the molecule or connected component you wish to minimize.
- Start minimization by clicking
Edit > Minimize.
Note: Minimizing a selected molecule brings the entire connected structure of the selected atom(s) into the calculation scope. For minimizing only a specific structural part, refer to the techniques outlined in this section.
A More Granular Approach: Minimizing Parts of a Molecule
If you wish to exclude specific parts of a molecule from optimization, you can use SAMSON’s freeze feature. By freezing atoms, you prevent them from moving during the minimization process. They stay in their fixed positions, allowing minimization to focus only on selected parts.
Here’s how you can minimize a specific portion of a molecule:
- Select the entire molecule or leave the selection empty.
- Click
Edit > Freezeto fix atoms in place. - Select the specific parts of the molecule to be minimized.
- Click
Edit > Unfreezeto allow movement only for the selected atoms. - Start minimization with
Edit > Minimize. - When done, stop minimization or unfreeze the entire system using
Edit > Unfreeze.
Frozen atoms are visually distinguishable with a dark blue overlay in the viewport, ensuring clarity during workflows.
Conclusion
SAMSON’s interactive minimization tools provide modelers with precise control, intuitive workflows, and powerful customization. From working on entire systems to targeting individual sections, the platform ensures an adaptable and efficient geometry optimization experience. Explore these capabilities to simplify and refine molecular design workflows.
For a deeper dive into minimization techniques within SAMSON, visit the full documentation.
Note: SAMSON and all SAMSON Extensions are free for non-commercial use. Download SAMSON today at https://www.samson-connect.net.
