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Find units of transition dipole moment

  1. Jul 24, 2012 #1
    I have been trying to figure out which formula for the relationship between oscillator strength and transition dipole moment is correct.

    Wiki had the following formula:


    f = 4.703 \times 10^{29} \bar{v} \mu^{2}_{ge}\,\!


    \bar{v}\,\! is the mean absorption frequency of the band in cm–1

    \mu^{2}_{ge}\,\!, refers to the square of the transition dipole moment between the ground state and the excited state.

    What I am unsure about is how they got the value of the constants and the units for it.

    In another reference I had this formula:

    f =[(8*pi*massofelectron)/(3*planck's const*electric)charge^2)] *vbar*u^2

    When I calculate the constant using this formula I get 4.49 * 10^41. Moreover I am also confused about whether vbar is frequency or wavenumber. Since wavenumber is in cm^-1 the units don't cancel out and f is no longer dimensionless. Has anyone done this kind of calculation?

    The values that I have in order to calculate the transition dipole moment is energy and f.

    I use E = planck's const*frequency to get frequency and then c= frequency*wavelenth to get the wave number and plug it in the equation. In either case the value I get is very off. Can you please help me figure out where I am missing the point?
  2. jcsd
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