What is the Difference Between Lennard Jones and Morse Potential

The key difference between Lennard Jones and Morse potential is that Lennard Jones potential provides a comparatively less accurate and less generalized description, whereas Morse potential provides a more accurate and generalized description for modeling covalent material and surface interactions.

Both Lennar Jones potential and Morse potential are important potential energy models we can use to determine the interactions between atoms or molecules.

1. Overview and Key Difference
2. What is Lennard Jones Potential
3. What is Morse Potential
4. Lennard Jones vs Morse Potential in Tabular Form
5. Summary – Lennard Jones and Morse Potential

What is Lennard Jones Potential?

Lennar Jones potential is a type of intermolecular pair potential. It can be described as the potential energy of interaction between two non-bonding atoms or molecules depending on the distance of separation. This potential was first described by Sir John Edward Lennar-Jones.

Lennard Jones and Morse Potential - Side by Side Comparison

Figure 01: An Example of Lennar Jones Potential Graph

Among other intermolecular potentials, the Lennar Jones potential is the one that has been studied most extensively. We can consider it as an archetype model for simple and realistic intermolecular interactions. This potential can model the sift repulsive and attractive interactions. Therefore, it tends to describe electronically neutral atoms or molecules.

Lennar Jones potential is a simplified model that can describe the essential features of the interactions between two or more simple atoms or molecules. The two interacting particles may repel each other at a close distance and can attract each other at a moderate distance. However, they do not interact at an infinite distance.

Moreover, we can use computer simulations and statistical mechanics to study the Lennar Jones potential and to obtain thermophysical properties of the Lennard-Jones substance. We can define both Lennar-jones potential and Lennard-jones substance as simplified but realistic models that can accurately capture the essential physical principles, including the presence of a critical and a triple point, condensation, and freezing.

What is Morse Potential?

Morse potential is a convenient interatomic interaction model for the potential energy of a diatomic molecule. It was first described by the physicist Phillip M. Morse. It gives a better approximation for the vibrational structure of the molecule than the quantum harmonic oscillator since it explicitly includes the effects of bond breaking, e.g. the existence of unbound states.

Lennard Jones vs Morse Potential in Tabular Form

Figure 02: A Graph Showing a Sample Morse Potential

Moreover, the Morse potential accounts for the anharmonicity of real bonds and the non-zero transition probability for the overtone and combination bands. Moreover, we can use this model for other interactions, including the interaction between an atom and a surface. It is very simple, which makes it not suitable for modern spectroscopy.

What is the Difference Between Lennard Jones and Morse Potential?

Both Lennar Jones potential and Morse potential are important potential energy models we can use to determine the interactions between atoms or molecules. The key difference between Lennard Jones and Morse potential is that Lennard Jones potential provides a comparatively less accurate and less generalized description, whereas Morse potential provides a more accurate and generalized description for modeling covalent material and surface interactions.

Below is a summary of the difference between Lennard Jones and Morse potential in tabular form for side by side comparison.

Summary – Lennard Jones vs Morse Potential

Lennar Jones potential is a type of intermolecular pair potential that can be described as the potential energy of interaction between two non-bonding atoms or molecules depending on the distance of separation. Morse potential is a convenient interatomic interaction model for the potential energy of a diatomic molecule. The key difference between Lennard Jones and Morse potential is that Lennard Jones potential provides a comparatively less accurate and less generalized description, whereas Morse potential provides a more accurate and generalized description for modeling covalent material and surface interactions.

Reference:

1. “Lennard-Jones Potential.” Chemistry LibreTexts, Libretexts, 15 Aug. 2020.

Image Courtesy:

1. “Graph of Lennard-Jones potential” By TimeStep89 – Wikipedia article. (CC BY 4.0) via Commons Wikimedia
2. “Morse-potential” By Somoza assumed – No machine-readable source provided. Own work assumed (based on copyright claims) (CC BY-SA 3.0) via Commons Wikimedia