  It is shown that taking into account a recoil for radiation scattering in the
Ly-alpha line can lead to a noticable acceleration of primordial hydrogen
recombination. Thus for LambdaCDM model a decrease of ionization degree exceeds
1% for redshifts z in a range 800 - 1050 achieving approximately 1.3% at z=900.
Corresponding corrections to the cosmic microwave background power spectra can
achieve 1.1% for TT spectra and 1.7% for EE ones. Radiative transfer in these
calculations was treated in a quasistationary approximation. Numerical
solutions are also obtained in diffusion approximation for a nonstationary
problem of Ly-alpha line radiative transfer under partial frequency
redistribution with a recoil. An evolution of a local line profile is traced to
as well as an evolution of a relative number of uncompensated transitions from
2p state down to 1s one. It is shown that taking into account nonstationarity
of Ly-alpha line radiative transfer can lead to an additional acceleration of
primordial hydrogen recombination.
