  We have performed ab initio calculations of the frequency shift induced by a
static electric field on the cesium clock hyperfine transition. The
calculations are used to find the frequency shifts due to blackbody radiation.
Our result ($\delta \nu/E^2=-2.26(2)\times 10^{-10}$Hz/(V/m)$^2$) is in good
agreement with early measurements and ab initio calculations performed in other
groups. We present arguments against recent claims that the actual value of the
effect might be smaller. The difference ($\sim$ 10%) between ab initio and
semiempirical calculations is due to the contribution of the continuum spectrum
to the sum over intermediate states.
