One dimensional Coulomb potential

In summary, the potential V(x) is given by a piecewise function depending on the value of x. The time independent Schrodinger equation can be derived from this potential, and the ground state wave function can be found by considering the approximated equation for small x. However, to find the exact solution, the boundary condition X(0) = 0 must be applied, which will give the discrete spectrum of energy levels.
  • #1
ShayanJ
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Consider the potential below:
[itex]
V(x)=\left\{ \begin{array}{cc} -\frac{e^2}{4\pi\varepsilon_0 x} &x>0 \\ \infty &x\leq 0 \end{array} \right.
[/itex]
The time independent Schrodinger equation becomes:
[itex]
\frac{d^2X}{dx^2}=-\frac{2m}{\hbar^2} (E+\frac{e^2}{4\pi\varepsilon_0 x})X
[/itex]
I want to find the ground state wave function.This is how I did it:
[itex]
Y=\frac{X}{x} \Rightarrow x\frac{d^2Y}{dx^2}+2\frac{dY}{dx}+(\frac{2mE}{\hbar^2}x+\frac{me^2}{2 \pi \varepsilon_0\hbar^2})Y=0
[/itex]
But because bound states of this potential are for small x and the ground state has a very very small x,I assumed [itex] x\to 0 [/itex] and considered the approximated equation below:
[itex]2\frac{dY}{dx}+\frac{me^2}{2\pi \varepsilon_0 \hbar^2}Y=0[/itex],whose answer is [itex] Y=A\exp{ (-\frac{me^2}{4\pi \varepsilon_0 \hbar^2}x)} [/itex] and so [itex] X=Ax\exp{ (-\frac{me^2}{4\pi \varepsilon_0 \hbar^2}x)}[/itex]
My problems are:
1-There is noting in X that indicates it is the ground state.What should I do about it? Is it an issue at all?
2-How can I find energy levels?
Thanks
 
Last edited:
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  • #2
You have to solve the exact equation. Finally, applying the boundary condition
X(0) = 0
(because of the unfinite potential step) should deliver the discrete spectrum of solutions.
 

1. What is a one dimensional Coulomb potential?

A one dimensional Coulomb potential is a mathematical model that describes the electrostatic force between two charged particles in one dimension. It is derived from Coulomb's law, which states that the force between two charged particles is directly proportional to the product of their charges and inversely proportional to the square of the distance between them. In one dimension, this potential only takes into account the distance between the particles along a straight line.

2. How is the one dimensional Coulomb potential expressed mathematically?

The one dimensional Coulomb potential is expressed as V(x) = kQq/|x|, where V(x) is the potential energy between two particles with charges Q and q separated by a distance x, and k is the Coulomb constant (8.99 x 10^9 N·m^2/C^2).

3. What does the one dimensional Coulomb potential tell us about the behavior of charged particles?

The one dimensional Coulomb potential tells us that charged particles will experience a force that is directly proportional to the product of their charges and inversely proportional to the distance between them. This means that particles with opposite charges will be attracted to each other, while particles with like charges will repel each other.

4. How does the one dimensional Coulomb potential differ from the three dimensional Coulomb potential?

In one dimension, the Coulomb potential only takes into account the distance between particles along a straight line, while in three dimensions, it takes into account the distance between particles in all three directions. This means that the one dimensional potential is a simplified version of the three dimensional potential, and is only applicable in certain scenarios.

5. What are some real-world applications of the one dimensional Coulomb potential?

The one dimensional Coulomb potential is used in various fields, such as electrostatics, plasma physics, and quantum mechanics. It is also used to understand the behavior of charged particles in one dimension, which can be applied to systems such as charged particles in a wire or particles in a one-dimensional lattice structure. Additionally, the concept of the one dimensional Coulomb potential is important in understanding the behavior of particles in more complex systems, such as in three dimensions.

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