As a molecular modeler, you’ve likely faced challenges in specifying and selecting molecular bonding characteristics efficiently. Understanding bond attributes can save you time and help you improve your structural modeling accuracy. In this post, we’ll introduce you to SAMSON’s bond Node Specification Language (NSL) attributes. These attributes help identify specific bonds in molecular models with precision, using attributes like bond type, length, and order.
Why Are Bond Attributes Useful?
Molecular models often involve intricate networks of bonds, and distinguishing among these bonds is crucial when analyzing or refining a structure. With SAMSON’s NSL bond attributes, you can:
- Filter bonds based on their types (single, double, aromatic, etc.).
- Specify bond lengths or ranges to narrow down your focus.
- Analyze bonds by their numeric order or custom types.
In practice, this means greater efficiency when working with large, complex molecular systems.
Examples of Key Bond Attributes
The bond attribute space in SAMSON uses convenient short names, making it easier to create concise expressions for matching specific bonds. Here are some of the key attributes:
1. customType (b.ct)
The bond.customType attribute is useful when working with bonds that have specific custom types defined. It accepts integer values. For instance:
b.ct 0: Matches bonds with custom type 0.b.ct >= 0: Matches bonds with custom types greater than or equal to 0.b.ct 0:2: Matches bonds with custom types within the range 0-2.
2. length (b.len)
Need to locate bonds based on their length? The bond.length attribute makes it easy to set specific ranges or thresholds. Here are examples:
b.len >= 1.5A: Matches bonds with length greater than or equal to 1.5 angstroms.b.len 1.2A:1.4A: Matches bonds with length between 1.2 and 1.4 angstroms.b.len 0.15nm:2.1nm: Matches bonds with length between 0.15 and 2.1 nanometers.
3. order (b.o)
The bond.order attribute enables filtering by bond order and supports floating-point values. For example:
b.o >= 2: Matches bonds with an order of 2 or higher.b.o 1.5:3: Matches bonds with an order between 1.5 and 3.
4. type (b.t)
This powerful attribute identifies bonds based on predefined bond types. Supported bond types include single, double, triple, am (amide), ar (aromatic), and more. Examples include:
b.t s: Matches single bonds.b.t s,d: Matches both single and double bonds.b.t du,un: Matches dummy and undefined bonds.
These classifications allow for incredibly efficient filtering, especially helpful during molecular analysis or design iterations.
Conclusion
Bond attributes in SAMSON’s NSL are an indispensable tool for molecular modelers who need precision in selecting and analyzing molecular bonds. To learn more about these attributes and how they can be used, visit the full documentation page: SAMSON Bond Attributes.
SAMSON and all SAMSON Extensions are free for non-commercial use. Get started today by downloading the platform at SAMSON Connect.