Bullet Points

  • Cartesian vs Spherical cords
  • Examples used are 3D box, H-atom
  • Angular momentum

Angular momentum on z axis

$\hat{L}_{z}$ and $\hat{L}_{y}$ commute, but $\hat{L}_{x}$ and $\hat{L}_{y}$ do not

Bound States and Free particle

  • Similar to 2-d problems, there are “free” states and “bound”’ states.
  • We can use separation of variables in Cartesian/spherical coordinate systems.
  • Potential can be modeled by the following: $$ V(r) \propto -\frac{1}{r} \propto \frac{1}{\sqrt{ x^{2}+y^{2}+z^{2} }}

-\frac{\hbar^{2}}{2m} \left[ \frac{d^{2}\psi}{dx^{2}}+\frac{d^{2}\psi}{dy^{2}} +\frac{d^{2}\psi}{dz^{2}} \right]= E\psi(x,y,z)

\Psi(x,y,z) = \phi_{x}(x) \phi_{y}(y)\phi_{z}(z)