What does the potential barrier energy measure?

Click For Summary

Discussion Overview

The discussion revolves around the concept of potential barrier energy, particularly in the context of charged particles and containers. Participants explore qualitative and quantitative aspects of potential barriers, including classical interpretations and tunneling phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the qualitative meaning of potential barrier energy and its relation to classical potential barriers, suggesting that if a particle's energy is less than the barrier height, it cannot pass through.
  • Another participant defines potential barrier energy as part of the potential energy function, explaining that the barrier height corresponds to the minimum work needed to escape a container.
  • It is noted that containers are often designed to be leakproof, implying that the barrier energy could be considered infinite, but it can be quantified through tunneling equations based on particle behavior.
  • A participant describes the classical analogy of a ball in a bowl to illustrate how potential barriers can be finite, even in leakproof containers.
  • One participant introduces the scenario of a vacuum vessel with gas, emphasizing that the potential energy describes the work needed to move from one location to another.
  • Another participant highlights that if gas possesses enough kinetic energy, it could overcome the potential barrier of the container walls, equating this to tunneling, while noting the lack of a classical analogy for tunneling.

Areas of Agreement / Disagreement

Participants express varying interpretations of potential barrier energy and its implications, with no consensus reached on a singular definition or approach. Multiple competing views on the nature of potential barriers and their quantification remain evident.

Contextual Notes

Participants reference classical mechanics and quantum tunneling without resolving the complexities involved in these concepts. The discussion reflects differing assumptions about the nature of potential barriers in various contexts.

iScience
Messages
466
Reaction score
5
The energy of an incident charged particle refers to its kinetic energy. What does the potential barrier energy refer to qualitatively?

EDIT: Is it just in reference to the "potential barrier" in the classical sense? where if the particle has less than the energy V, then it doesn't go through?

Also, how would one go about quantifying the barrier energy of say, the walls of a container?
 
Last edited:
Physics news on Phys.org
Potential energy.
The barrier is part of the potential energy function.

The barrier height of the walls of a container would be the minimum work required to leave the container starting from the potential energy at the bottom.
i.e. to get mass m over a hill height h requires at least mgh work, so the potential barrier height of the hill is mgh.
 
  • Like
Likes   Reactions: dlgoff
Usually we design containers that are practically leakproof, so the barrier energy is effectively infinite. But you can quantify the barrier by measuring how many particles tunnel through it and putting it into a tunneling equation.
 
We usually make containers so it takes a finite amount of work to remove stuff from them.
This translates to a finite barrier height.

The classical picture of a potential well is something like a ball in a bowl... it rolls back and forth to a height depending on it's energy. Plot the bslls gPE vs horizontal position and you will see the barrier is finite even if the bowl sides are leakproof.
 
I guess it all depends on the problem at hand. I was picturing a vacuum vessel with gas inside.
 
OK. A bottle of gas then...
If you were to describe the container in terms of the potentials that were containing the gas, you would still be describing the amount of work needed to get from one place to another ... because that is what "potential energy" means. If the gas had the kinetic energy to punch through the walls, then it's energy level would be higher than the potential barrier describing the walls.
Punching through the walls, in this case, is the same as going over the potential barrier.

There is no decent classical analogy for tunnelling.
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
1K
  • · Replies 27 ·
Replies
27
Views
3K
  • · Replies 4 ·
Replies
4
Views
1K
Replies
1
Views
1K
  • · Replies 2 ·
Replies
2
Views
1K
  • · Replies 4 ·
Replies
4
Views
6K
  • · Replies 3 ·
Replies
3
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 7 ·
Replies
7
Views
3K