Introduction to the N-state model

The modelling of motion in molecules using experimental data consists of either continuous or discrete distributions. These can be visualised respectively as either an infinite number of states or a limited set of N states. The N-state model analysis in relax models the molecular dynamics using an ensemble of static structures.

This analysis supports a number of data types including:

The main idea is to evaluate the quality of a fixed ensemble of structures. relax will not perform structural optimisations. The evaluation includes:

Note that this analysis will also handle single structures. Hence you can use the N-state model in relax with N set to 1 to find, for example, a single alignment tensor for a single structure using RDCs, PCSs, or both together. This is useful for comparing a ensemble to a single structure to determine if any statistically significant motions are present.

The primary references for the N-state model analysis in relax are:

The relax user manual (PDF), created 2024-06-08.