Calculate energy of wavefunctions for a particle in infinite spherical well

In summary, the problem involves calculating the energy of wavefunctions 1s, 2p, and 3d for a particle in a 2nm sphere with infinite potential energy outside and zero potential energy inside. The solution involves solving the free particle for an arbitrary l, applying a boundary condition for the wave function at the surface of the sphere, and obtaining a transcendental equation for E.
  • #1
h2obrain
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Homework Statement


Consider a particle in a 2nm sphere with infinite potential energy outside and zero potential energy inside the sphere. Calculate the energy of the following wavefunctions: 1s, 2p, 3d


Homework Equations


H(hat) = p(hat)^2/2m(sub zero) + V(r)
V(r) = ∞ when r ≥ 2 nm
V(r) = 0 when r< 2 nm


The Attempt at a Solution


for 1s l=0
spherical Bessel fxn is j(sub zero)(x)=(sin x)/x
E(sub k0) = [(k(pi))^2*h(bar)^2]/[2m(sub 0)r(sub 0)^2]

I am so lost! Please help!
 
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  • #2
This problems are all solved by the same logic. First you should solve the free particle inside the sphere, which will give a solution on functions of the possition, that also depend on l (like the spherical Bessel functions).

Then apply the boundary condition that the wave function vanishes at the surface of the sphere (since you have infinite potential outside it), from this condition you'll find and equation something like j_l(alpha*R)=0. This is an equation for alpha, which will depend on the energy, so, summing up:

1: Solve the free particle for an arbitrary l.
2: Apply boundary condition for the wave function to in the surface of the sphere.
3: You should get a trascendental equation for E.

Hope this helps. (sorry for the sloppy english)
 

FAQ: Calculate energy of wavefunctions for a particle in infinite spherical well

What is the formula for calculating the energy of a particle in an infinite spherical well?

The formula for calculating the energy of a particle in an infinite spherical well is En = (n2h2)/(8ma2), where n is the principal quantum number, h is Planck's constant, m is the mass of the particle, and a is the radius of the well.

What is the significance of the energy levels in an infinite spherical well?

The energy levels in an infinite spherical well represent the allowed energy states that a particle can occupy within the well. These levels are quantized, meaning they can only take on discrete values, and they determine the probability of finding the particle at a certain energy level.

How does the energy of a particle in an infinite spherical well vary with the principal quantum number?

The energy of a particle in an infinite spherical well is directly proportional to the square of the principal quantum number. This means that as the principal quantum number increases, so does the energy of the particle. This relationship is represented by the formula En = (n2h2)/(8ma2).

Can the energy of a particle in an infinite spherical well have a negative value?

No, the energy of a particle in an infinite spherical well cannot have a negative value. This is because the particle is confined within the well and cannot have any energy lower than the lowest allowed energy state, which is E1 = (h2)/(8ma2).

How does the energy of a particle in an infinite spherical well compare to the energy of a free particle?

The energy of a particle in an infinite spherical well is quantized, meaning it can only take on discrete values. In contrast, the energy of a free particle can have any value within a continuous range. Additionally, the energy levels in an infinite spherical well are determined by the size of the well and the mass of the particle, while the energy of a free particle is determined by its velocity and mass.

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