Interaction energy
Encyclopedia
In physics
, interaction energy is the contribution to the total energy
that is caused by an interaction
between the objects being considered.
The interaction energy usually depends on the relative position of the objects. For example,
is the electrostatic
interaction energy between two objects with charges
, 
.
,
where
and 
are the energies of the isolated objects (monomers), and 
the energy of their interacting assembly (dimer).
For larger system, consisting of N objects, this procedure can be generalized to provide a total many-body interaction energy:
.
By calculating the energies for monomers, dimers, trimers, etc., in an N-object system, a complete set of two-, three-, and up to N-body interaction energies can be derived.
The supermolecular approach has an important disadvantage in that the final interaction energy is usually much smaller than the total energies from which it is calculated, and therefore contains a much larger relative uncertainty.
Physics
Physics is a natural science that involves the study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.Physics is one of the oldest academic...
, interaction energy is the contribution to the total energy
Energy
In physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
that is caused by an interaction
Interaction
Interaction is a kind of action that occurs as two or more objects have an effect upon one another. The idea of a two-way effect is essential in the concept of interaction, as opposed to a one-way causal effect...
between the objects being considered.
The interaction energy usually depends on the relative position of the objects. For example,
is the electrostaticElectrostatics
Electrostatics is the branch of physics that deals with the phenomena and properties of stationary or slow-moving electric charges....
interaction energy between two objects with charges
, .Supermolecular interaction energy
A straightforward approach for evaluating the interaction energy is to calculate the difference between the energies of isolated objects and their assembly. In the case of two objects, A and B, the interaction energy can be written as:,where
and are the energies of the isolated objects (monomers), and the energy of their interacting assembly (dimer).For larger system, consisting of N objects, this procedure can be generalized to provide a total many-body interaction energy:
.By calculating the energies for monomers, dimers, trimers, etc., in an N-object system, a complete set of two-, three-, and up to N-body interaction energies can be derived.
The supermolecular approach has an important disadvantage in that the final interaction energy is usually much smaller than the total energies from which it is calculated, and therefore contains a much larger relative uncertainty.
See also
- EnergyEnergyIn physics, energy is an indirectly observed quantity. It is often understood as the ability a physical system has to do work on other physical systems...
- ForceForceIn physics, a force is any influence that causes an object to undergo a change in speed, a change in direction, or a change in shape. In other words, a force is that which can cause an object with mass to change its velocity , i.e., to accelerate, or which can cause a flexible object to deform...
- InteractionInteractionInteraction is a kind of action that occurs as two or more objects have an effect upon one another. The idea of a two-way effect is essential in the concept of interaction, as opposed to a one-way causal effect...
- Perturbation theory (quantum mechanics)Perturbation theory (quantum mechanics)In quantum mechanics, perturbation theory is a set of approximation schemes directly related to mathematical perturbation for describing a complicated quantum system in terms of a simpler one. The idea is to start with a simple system for which a mathematical solution is known, and add an...
- PotentialPotential*In linguistics, the potential mood*The mathematical study of potentials is known as potential theory; it is the study of harmonic functions on manifolds...