Hyperfine structure transition of Cs-133: calculation?

[Marco Masi]

I'm looking for the theoretical calculation of the hyperfine structure transition frequency of Ca-133 which is used in atomic clocks to define the second according to SI-Units. Google, Google... there is a lot about the hyperfine Hamiltonian of hydrogen, but couldn't find none about that of Ca-133. I would like to see how that famous 9,192,631,770 Hz frequency which defines our earthly time standard is calculated through theory. Can anyone help?

 

[blue_leaf77]

I think it should be Caesium not Calsium.

 

[Marco Masi]

I think it should be Caesium not Calsium.

Opss... You are right, Cs-133... not Ca. Thanks.