Potential Energy of a Pair of Neutral Atoms
by Charlotte Bunch
Potential Energy of a Pair of Neutral Atoms
At first glance it seems silly to think that there would be any kind of interaction between two neutral atoms because they are in fact neutral. This means that there are equal amounts of positive and negative charges in the atom therefore resulting in a zero net charge on each. However, this is not the case due to the way the election cloud around each nucleus behaves at certain distances.
A Mathematical Model
We know that interactions between atoms are similar to the behavior of a spring. And we can approximate the formula for interatomic potential energy as[math]\displaystyle{ U = (1/2)ks^2 - E_M }[/math]
When graphed, this equation gives us
However the potential energy needs to reach zero as the atoms get further apart. The Morse approximation accounts for this.
- Morse approximation
- [math]\displaystyle{ U_M = E_M*[1-e^{-α(r-r_{eq})}]^2 - E_M }[/math]
The new graph looks like this INSERT GRAPH
A Computational Model
How do we visualize or predict using this topic. Consider embedding some vpython code here Teach hands-on with GlowScript
Simple Example
There are three cases that describe the potential energy between two neutral atoms.
- Far apart:
There is relatively no force on each atom due to the other because the forces of attraction and repulsion of like and unlike charges pretty much cancel out. - Close together:
Polarization distorts the electron cloud in such a way that the two atoms feel an attractive force towards each other. Solid objects are held together by this electric force of attraction. - Much closer:
As the two atoms are pushed closer and closer together they will begin to repel. This is because of the positions of the protons and electrons.
Connectedness
- How is this topic connected to something that you are interested in?
- How is it connected to your major?
- Is there an interesting industrial application?
History
Philip Morse
The Morse approximation is accredited to Philip Morse, who wrote a paper around 1930 about interatomic interactions. He was an engineer and physicists who wanted to get physically applicable results to his findings. Because of this he went on to assist the United States in World War II. He discovered a way to use acoustics to aid the US in detonating German mines.
See also
Are there related topics or categories in this wiki resource for the curious reader to explore? How does this topic fit into that context?
Further reading
Books, Articles or other print media on this topic
External links
Internet resources on this topic