Recent content by JulienB

If it interests somebody, at the end I took the general expression for hydrogen-like atoms of Bethe & Salpeter, derived in their book "Quantum Mechanics of One- and Two-Electron Atoms". The excerpt where the equation (eq. (22.12)) is can be found here...

@Charles Link Hi and thanks for your answer. So you say that the wave functions are the same? Julien.

Homework Statement Hi everybody! Here is the problem: Hyperfine splitting of Deuterium Balmer alpha line: Consider the ##3p_{3/2}## to ##2s_{1/2}## transition in deuterium. Find the number of transition lines and their frequency shifts with respect to the transition without hyperfine...

Homework Statement Hi everybody! I have a problem related to first-order perturbation theory, and I'm not sure I'm tackling the problem correctly. Here is the problem: Consider a hydrogen atom in an externally applied electric field ##\vec{F}##. Use first-order perturbation theory to find the...

@TSny Ah yes, I oversaw the x,y,z dependence indeed. Your explanation makes sense about the basis. I think I can close this topic now, thank you very much for your input. Julien.

Okay here is my new attempt: ##\psi_{220}(r,\theta)=\sqrt{\frac{16}{15}} \frac{1}{\sqrt{\pi}} \left( \frac{\hbar}{m\omega} \right)^{1/4} \left( \frac{m\omega}{\hbar} \right)^2 r^2 e^{-\frac{m\omega}{2\hbar} r^2} \sqrt{\frac{5}{16\pi}} (3 \cos^2\theta-1)## ##=\frac{1}{\sqrt{3}\pi} \left(...

@TSny Oops sorry I made a mistake. ##m=0## in the problem. My bad. @vela Good point, I didn't realize that... Okay I guess I go back to the drawing board, I will post my progress as soon as I have something. Thank you very much for your help. Julien.

Homework Statement Hi everybody! In my quantum mechanics introductory course we were given an exercise about the 3D quantum harmonic oscillator. We are supposed to write the state ##l=2##, ##m=2## with energy ##E=\frac{7}{2}\hbar \omega## as a linear combination of Cartesian states...

@vela Thanks for your answer. Indeed I didn't know how to numerically integrate using Matlab until now. Thanks a lot, I got now the same result as you!Julien.

I found the mistake, it was in my first substitution: either I forgot a ##-## or to invert the limits of integration. The result is now ##R_\text{visible} = 18.493##kW##\cdot##m##^{-2}## which represents about ##4{\%}## of the total electromagnetic power. I think it is a reasonable figure, what...

Actually I made a typing mistake in Matlab. The result is now ##R_\text{visible}= -18.493##kW##\cdot##m##^{-2}## which is better than before, except for the minus sign. Maybe I inverted my limits of integration by mistake somewhere.

Homework Statement Hi everybody! I am asked to calculate how much of the total radiated power of a light bulb at temperature ##T=2300##K is contained within ##400##nm and ##750##nm. I am also given the average emissivity of tungsten ##\epsilon_\text{ave}=0.288## and the emissivity within the...

@Bandersnatch thanks again for your answers, that pretty much cleared up my confusion (...for now :) ). Thanks I will check it out. I think I cannot guess further without knowing more. Oh so it is only light pollution from the Milky Way you mean? Crazy! And thanks for all those links you've...

Hi and thanks for your answer. I am aware that the anisotropies are tiny, but still the GHz maps (whether the wavelengths have been shifted or not) have this white light splitting the sphere into two (which the temperature mapping does not have). Do you happen to know more about that? Julien.

Hi and thanks @PeterDonis and @Bandersnatch for your very interesting answers! If I may, I'd like to ask @Bandersnatch a few specifications about what you are saying. Yes I actually do think of the Big Bang as you describe it, i.e. matter escaping an infinitesimal volume. I'd like to emphasize...