# Semi-flexible trimers on the square lattice in the full lattice limit

## TL;DR

This study investigates the thermodynamic properties of semi-flexible trimers on a square lattice, analyzing how their entropy varies with angular flexibility using transfer matrix methods in the full lattice limit.

## Contribution

It introduces a model for semi-flexible trimers with variable angular weights and computes the entropy across different configurations, extending previous studies on straight and angular trimers.

## Key findings

- Maximum entropy occurs at equal weights for straight and angular configurations.
- Entropy varies smoothly with the angular weight parameter , .
- Results align with and extend earlier findings for specific trimer types.

## Abstract

Trimers are chains formed by two lattice edges, and therefore three monomers. We consider trimers placed on the square lattice, the edges belonging to the same trimer are either colinear, forming a straight rod with unitary statistical weight, or perpendicular, a statistical weight $\omega$ being associated to these angular trimers. The thermodynamic properties of this model are studied in the full lattice limit, where all lattice sites are occupied by monomers belonging to trimers. In particular, we use transfer matrix techniques to estimate the entropy of the system as a function of $\omega$. The entropy $s(\omega)$ is a maximum at $\omega=1$ and our results are compared to earlier studies in the literature for straight trimers ($\omega=0$), angular trimers ($\omega \to \infty$) and for mixtures of equiprobable straight and angular trimers ($\omega=1$).