Carbon nanotubes (CNTs) have become essential structures in nanotechnology, offering unique electrical, mechanical, and chemical properties. Researchers often need to create them for simulations or structural modeling. However, what should be a straightforward task often turns into a tedious one: building nanotubes atom-by-atom or importing ready-made models can lack flexibility when you want full control over geometry or bond alignments.
In this post, we present a practical, step-by-step method for constructing custom carbon nanotubes directly in SAMSON using pattern builders. This approach is not only intuitive but also allows precise control over each step, from ring construction to tubular replication. You can build nanotubes adapted to your pipeline — whether you’re doing quantum calculations, coarse-grained modeling, or simply visualizing nanostructures.
Why build nanotubes manually?
- ⚙️ Custom geometry: You can tweak ring size, interlayer spacing, and orientation.
- 🔄 Interactive control: Widgets make it easy to rotate, translate, and replicate structures precisely.
- 🔬 Better simulation prep: Build structures you know are aligned and chemically meaningful before minimization.
Step-by-step nanotube construction
- Create a ring structure
Start with a basic carbon ring. You can build this manually or use existing templates. Remove hydrogen atoms if necessary to allow bonding downstream. Use the rotation tools to align ring edges properly. - Activate the Circular Pattern Editor (W)
This will replicate the ring around a central axis. Increase the number of copies (e.g., 12) to form a closed circular structure. Adjust the radius until adjacent atoms are close enough to form bonds. Click Accept when satisfied. - Align your ring
Use the Edit > Align functionality to snap your ring onto a known plane, such as the XY plane. This ensures your nanotube will grow uniformly along an axis. - Activate the Linear Pattern Editor (L)
Now stack your ring along the Z-axis to replicate it into a tube. Use a translation increment of about 2 Å to maintain realistic bond lengths. If needed, add a small rotational twist between rings to match bonding preferences. Again, use the on-screen widget or numeric inputs for accuracy. - Accept and minimize
Finalize the tube structure by accepting the pattern. Use the Minimize tool to relax atomic positions and add hydrogens if required. This ensures the geometry is chemically valid for simulations.
Result: A custom carbon nanotube
The resulting structure can now be functionalized, simulated, or exported. Built from the ground up, it will match your specific needs — be it radius, chirality, or length. You can always go back and adjust parameters to explore different configurations.
This approach empowers you to create nanostructures directly, interactively, and without scripting. To see this method in action, check out the related tutorial extract from the SAMSON 2025 webinar.
To learn more about circular and linear pattern tools, visit the official SAMSON documentation page on Creating Patterns.
SAMSON and all SAMSON Extensions are free for non-commercial use. Download it at https://www.samson-connect.net.