Quantum Mechanics: Substitution and Coulomb Potential in Schrodinger Equation

spaghetti3451
Messages
1,311
Reaction score
31

Homework Statement



(i) Briefly indicate how substitution of operators corresponding to dynamical variables in an eigenvalue equation leads to the Schrodinger equation \left( \frac{-ħ^{2}}{2m} ∇^{2} + V \right)ψ = Eψ.

(ii) What is the Coulomb potential, V(r), of an electron, charge e, in a hydrogen atom at distance r from the nucleus?

(iii), (iv), (v) left out for the moment

Homework Equations



The Attempt at a Solution



(i) (T + V) = E : law of conservation of energy

Multiply by ψ to obtain an eigenvalue equation: (T + V)ψ = Eψ

Substitute operators \widehat{T} and \widehat{V} corresponding to the dynamical variables T and V in the eigenvalue equation: ( \widehat{T} + \widehat{V} ) ψ = Eψ

\widehat{T} = \frac{\widehat{p}^{2}}{2m} = \frac{(-iħ∇)^{2}}{2m} = \frac{-ħ^{2}}{2m} ∇^{2}

\widehat{V} = V

So, the eigenvalue equation becomes the Schrodinger equation \left( \frac{-ħ^{2}}{2m} ∇^{2} + V \right)ψ = Eψ.(ii) V(r) = \frac{-e^{2}}{4πε₀r}

Any comments would be greatly appreciated.
 
Physics news on Phys.org
yep, your answers look good to me.
 
Thread 'Need help understanding this figure on energy levels'
This figure is from "Introduction to Quantum Mechanics" by Griffiths (3rd edition). It is available to download. It is from page 142. I am hoping the usual people on this site will give me a hand understanding what is going on in the figure. After the equation (4.50) it says "It is customary to introduce the principal quantum number, ##n##, which simply orders the allowed energies, starting with 1 for the ground state. (see the figure)" I still don't understand the figure :( Here is...
Thread 'Understanding how to "tack on" the time wiggle factor'
The last problem I posted on QM made it into advanced homework help, that is why I am putting it here. I am sorry for any hassle imposed on the moderators by myself. Part (a) is quite easy. We get $$\sigma_1 = 2\lambda, \mathbf{v}_1 = \begin{pmatrix} 0 \\ 0 \\ 1 \end{pmatrix} \sigma_2 = \lambda, \mathbf{v}_2 = \begin{pmatrix} 1/\sqrt{2} \\ 1/\sqrt{2} \\ 0 \end{pmatrix} \sigma_3 = -\lambda, \mathbf{v}_3 = \begin{pmatrix} 1/\sqrt{2} \\ -1/\sqrt{2} \\ 0 \end{pmatrix} $$ There are two ways...
Back
Top