Measurement of the oscillator strength of the E2 transition Cs(6S-5D)

We have measured the transition probability of the elctric quadrupole transition Cs (6S-5D) as 21 +- 1.5 s-1 using two-photon ionization of the ground state 6S, and the 5D as an intermediate state. It was previously measured by a number of methods with conflicting results. Our measurement is in agreement with a laser absorption-fluorescence measurement, and in disagreement with the results of anomalous dispersion, emission, and electron impact techniques. Our result is in agreement with a very recent relativistic calculation. (orig.)