A New Angle: Choosing Spherical Coordinates Instead of RectangularTaking a Good Look at Central Potentials in 3DBreaking down the Schrödinger equationThe angular part of ψ(r, θ, ϕ)The radial part of ψ(r, θ, ϕ)Handling Free Particles in 3D with Spherical CoordinatesThe spherical Bessel and Neumann functionsThe limits for small and large ρHandling the Spherical Square Well PotentialInside the square well: 0 < r < aOutside the square well: r > aGetting the Goods on Isotropic Harmonic Oscillators