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Homework Help: Atomic Spectra

  1. Feb 28, 2006 #1
    A molecule with angular momentum L and moment of inertia I has a rotational energy [tex]E = L^2 / 2I[/tex]. Since angular momentum is quantized, find the wavelength of the photons emitted in n=2 to n=1 transition of the H2 molecule. This molecule has a moment of inertia [tex]I = [tex]0.5mr^2[/tex], where m = 938Mev/c^2 and r = 0.074nm.

    My attempt is to say [tex]L = [[l(l+1)]^.5}\hbar[/tex] and use l =2 for n=2 state and l = 1 for n=1. Put these values for L into the equation for E.
    Then E2 - E1 = [tex] \triangle E. [/tex]

    [tex] \triangle E = hf, v = \lambda f. [/tex]

    => [tex] \lambda = hv / \triangle E = hc / \triangle E [/tex]

    I've no idea if I'm on the right track, couldn't find anything similar in the textbook.
    Last edited: Feb 28, 2006
  2. jcsd
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