1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Probability of a spin flip transition in neutral hydrogen

  1. Nov 29, 2013 #1
    1. The problem statement, all variables and given/known data

    I'd like to calculate the probability of a spin flip transition occurring in the ground state of neutral hydrogen. That is, the transition from parallel to anti-parallel spin configuration of the electron and proton. This transition produces the 21-cm line.

    2. Relevant equations


    3. The attempt at a solution

    The answer is well known to be [tex] 2.9\times10^{-15} s^{-1} [/tex]
    but I'm not sure how to get there. Right now I'm mostly just looking for a rough outline of what it would take.
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?