Recent content by Lunar_Lander

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    Spin dynamics and Larmor precession

    Homework Statement Consider an electron with spin, which should be in a homogenous magnetic field B=B0ez. This situation is described by the Hamiltonian of the shape \hat{H}=g\frac{\mu_B}{\hbar}\textbf{BS}. Consider now the time dependent state |\psi(t)> of the electron in spin space. The...
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    Optimizing Hydrogen Atom Wave Function Expectation Values

    I think I got <V>, the first solution I posted was from the indefinite integral. A^2\frac{e_0^2}{\epsilon_0}\int_0^{\infty}\exp(-2\alpha~r)r~dr A^2\frac{e_0^2}{\epsilon_0}\cdot\frac{1}{4\alpha^2}=\frac{e_0^2\alpha}{4\pi\epsilon_0}. Also, A can be found by normalizing the original wave...
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    Expectation Values of Radii in the Hydrogen Atom

    I think I got it now. First of all I learned that the 2p energy level is degenerate, thus m should have no influence on it and there is only one calculation to do for 2p. Then I tried to calculate 1s: \psi_{1s}=\frac{1}{\sqrt{\pi}}(\frac{Z}{a_0})^{3/2}\exp(-\frac{Zr}{a_0}) As we are...
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    Expectation Values of Radii in the Hydrogen Atom

    I also attempted a run at the 2p (for m=0) and it looks like this: \psi_{2p_0}^2=\frac{1}{32\pi\cdot a_0^5}\cdot r^2Z^5\exp(-\frac{2Z\cdot r}{a_0})\cdot\cos^2(\theta) <r>=\frac{1}{32\pi\cdot a_0^5}\int_0^r \int_0^{\pi} \int_0^{2\pi} r^2Z^5\exp(-\frac{2Z\cdot...
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    Expectation Values of Radii in the Hydrogen Atom

    Homework Statement Determine for the hydrogen atom states 1s and 2p the expectation value of the radius r and the associated mean square error Δr. Homework Equations Wave Functions for 1s and 2p from Demtroeder's Experimental Physics Volume 3 (it says "The normalized complete...
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    Optimizing Hydrogen Atom Wave Function Expectation Values

    Sorry, I had once seen this notation (T=\frac{\hbar}{2m}\Delta) somewhere. Would it rather be: <T>=-\int\int\int r^2\cdot\sin(\theta)\cdot\psi^2\cdot\frac{\hbar}{2m}\Delta\psi~dr~d\theta~d\phi ? I'll try the limits later on, but thanks for the help already :)!
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    Optimizing Hydrogen Atom Wave Function Expectation Values

    So, I am getting this: -4\pi\cdot A^2\frac{e_0^2}{4\pi\epsilon_0}\int \exp(-\alpha\cdot r)\cdot r~dr -A^2\frac{e_0^2}{\epsilon_0}\int \exp(-\alpha\cdot r)\cdot r~dr and A^2\frac{e_0^2}{\epsilon_0}\cdot \frac{1-\exp(-\alpha\cdot r)\cdot (\alpha\cdot r+1)}{\alpha^2} Is this correct? If...
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    Optimizing Hydrogen Atom Wave Function Expectation Values

    Thank you Vela! Would it maybe be possible for one of you to show me just how to correctly do this calculation, because my problem is that I usually need a good example and explanation on how to calculate complex things. When I look at calculations in books, those are usually good, but when I...
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    Optimizing Hydrogen Atom Wave Function Expectation Values

    "Optimizing" a Wave Function Homework Statement Consider a Hydrogen Atom, an electron in an attractive Coulomb potential of the form V(r)=-\frac{e_0^2}{4\pi\epsilon_0r}, where e0 is the elementary charge. Assume the following wave function for the electron (with α>0): \psi(r)=Ae^{-\alpha...
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    Wave Functions in a Potential Well with infinite high walls

    Homework Statement Consider a potential well with infinite high walls, i.e. V(x)=0 for -L/2\leq x \leq +L/2 and V(x)=\infty at any other x. Consider this problem (the first task was to solve the stationary Schroedinger equation, to get the Energies and Wave Functions, especially for n=1 and...
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    Free Particle and the Schroedinger Equation

    Ah, thank you! When I take the complex conjugate of ψ for taking the square, then I get \rho(x,t=0)=\frac{1}{\sqrt{2\pi}d}\exp[-\frac{(x-x_0)^2}{2d^2}]. Looks like a gaussian bell curve to me from the form of the equation. Could that be it?
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    Free Particle and the Schroedinger Equation

    An addendum, just received an E-Mail from the professor, who said that due to many people having difficulties, he would give the solution for ψ, and he said it looks like this: \psi(x,0)=\frac{1}{\pi^{1/4}\cdot 2^{1/4}\cdot d_0^{1/2}}\exp[i\cdot k_0(x-x_0)]\exp[-\frac{(x-x_0)^2}{4d_0^2}]...
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    Free Particle and the Schroedinger Equation

    Homework Statement Consider the time-dependent one-dimensional Schroedinger Equation for the free particle, i.e. let the Potential be V(x)=0. Consider a wave packet, i.e. \psi(x,t)=\int_{-\infty}^{\infty}=A(k)\exp[i(kx-\omega(k)t]dk. Consider especially the Amplitude distribution...
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    How Does Charge Interaction Affect Spring Dynamics?

    Homework Statement Charge Q1 is fixed to the ceiling by means of a spring with the spring constant D and is moved from its rest position (which is at y=h) by the two charges Q2. The gravitational force may be neglected. a) Determine the resulting force on Q1 in dependency of y. b) The...
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    What is the focal length of the second lens in an afocal system?

    For clarification, here is a picture of the system I am asking about.
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