tex2html_wrap171 . No coupling to tex2html_wrap172 so can ignore spin. In the ground state tex2html_wrap173 so tex2html_wrap174 . For the ground state, this is 0 to first order.

In second order, you get: tex2html_wrap175 . numerator not 0 for l=1 and n tex2html_wrap176 1. Approximation gives: tex2html_wrap177


tex2html_wrap179 tex2html_wrap180

tex2html_wrap181 tex2html_wrap182 = quadratic stark effect. Polarization= tex2html_wrap183 . Polarizability= tex2html_wrap184 polarization. This is tex2html_wrap185 . Actual calculation gives tex2html_wrap186 which agrees well with experimentation.

For excited states:

For n=2, there is 8 fold degeneracy

With spin orbit coupling, you get a 6 fold degeneracy on tex2html_wrap187 .

Weak fileds - tex2html_wrap176 non-degenerate P.T. = tex2html_wrap176 2nd order quadratic.

Strong fields, then 2s and 2p are degenerate.

tex2html_wrap190 . Constructing a 4x4 matrix, you get:

tex2html_wrap191 . Diagonilizing, you get: the roots, 0,0, tex2html_wrap192 . The eigen states are tex2html_wrap193 , tex2html_wrap194 . This is the linear stark effect. Only shows up for strong fields, when lamb shifts and spin orbit coupling are neglectable. This means tex2html_wrap195 .

psfile jl@crush.caltech.edu index