For molecular modelers, refining and efficiently navigating molecular structures is a vital part of the workflow. One of the challenges is finding ways to precisely query and manipulate bond-level data. Thanks to SAMSON’s Node Specification Language (NSL), you can address this pain point with ease by using bond attributes to filter and query molecular bonds based on specific criteria.
Bond attributes in NSL provide a dedicated space for defining bond-related queries, making molecular modeling more efficient and productive. Here’s what you need to know about how bond attributes work, their types, and how to use them effectively in SAMSON’s powerful framework.
What Are Bond Attributes in NSL?
In SAMSON, bond attributes are defined within the bond attribute space (short name: b). These attributes apply specifically to bond nodes and allow users to match bonds against certain conditions. The flexibility of these attributes means you can fine-tune your search criteria, whether it involves bond lengths, order, or type.
Key Bond Attributes
Below are the main attributes related to bond nodes and their practical applications.
- Custom Type (
customType, short name:b.ct)
This attribute helps you match bonds with specific custom integer types. For example:b.ct 0: Matches bonds with custom type 0.b.ct >= 0: Matches bonds with custom type equal to or higher than 0.b.ct 0:2: Matches bonds with custom types between 0 and 2.
- Length (
length, short name:b.len)
This attribute matches bonds with specific lengths, either in angstroms or nanometers. Some examples include:b.len >= 1.5A: Matches bonds longer than 1.5 angstroms.b.len 1.2A:1.4A: Matches bonds with lengths between 1.2 and 1.4 angstroms.b.len 0.15nm:2.1nm: Matches bonds with lengths between 0.15 and 2.1 nanometers.
- Order (
order, short name:b.o)
This attribute matches bond orders using floating-point values. For example:b.o >= 2: Matches bonds with orders of 2 or greater.b.o 1.5:3: Matches bonds with orders between 1.5 and 3.
- Type (
type, short name:b.t)
This attribute is used to match bonds of specific chemical types, such as single, double, or aromatic bonds. Here are a few practical examples:b.t s: Matches single bonds.b.t s,d: Matches both single and double bonds.b.t ar: Matches aromatic bonds.
Note: The bond must have its type defined to use this attribute effectively.
Why Use Bond Attributes?
Bond attributes allow you to:
- Efficiently locate specific structural features in complex molecules.
- Identify bonds with non-standard lengths or types for further analysis.
- Query specific chemical environments, such as aromatic rings or triple bonds.
For example, a typical use case might involve selecting all double bonds (b.t d) longer than 1.3 angstroms (b.len > 1.3A) to prioritize these in optimization workflows.
By mastering bond attributes, molecular designers and modelers can streamline their workflows and quickly access relevant data, freeing time for critical decision-making and experimentation.
Learn More
Interested in exploring more about bond attributes and their applications? Head over to the official SAMSON documentation for bond attributes: https://documentation.samson-connect.net/users/latest/nsl/bond/.
SAMSON and all SAMSON Extensions are free for non-commercial use. You can get SAMSON at https://www.samson-connect.net.