Recent content by Rafael

is derived from: But ρ is the free charge: $$ρ = \nabla \cdot D$$ In a system with just a electrical polarizated material there isn`t free charge (ρ = 0), so the formula above should predict that the total energy is 0.

In electrostatics, for what I understand the when I have an electric field, the density of the energy stored in it is given by the following formula: $$W = \frac{1 }{2} E \cdot D$$But when there is some material permantent polarization the above formula fails to work. Is this correct? How can...

I'm a bit confused because I have't studied perturbation theory yet. So if we take account of electron repulsion and fine structure, what happens with the linear combination I have writted? Is it impossible for helium? Does it have more energy than the others? Thanks for the answer.

Most of the books I've seen they say that the first excited state of Helium (with two electrons, one in orbital 1s and other in 2s) can have the two electrons with parallel spin (orthohelium) or anti-parallel spin (parahelium). If ##\operatorname{X_{↑}}{\left (n \right )}## represent the state...

Hi, I'm having trouble understanding angular moment of the one electron hydrogen atom. Solving Schrödinger equation on a referece system (say S) I get the energy eigenstates. They depend on three quantum numbers, n, l, m \frac{-ħ}{2 m}\nabla^{2} \Psi - \frac{e^{2}}{4 \pi \epsilon r} \Psi =...