  Models of steady-state plane-parallel shock waves propagating through the
unperturbed hydrogen gas of temperature T=6000K and density rho = 1e-10 gm/cm^3
are computed for upstream velocities from 15 km/s to 70 km/s. The shock wave
structure is considered in terms of the self-consistent solution of the
radiation transfer, fluid dynamics and rate equations for 2 <= L <= 4 atomic
bound levels with a continuum. The radiative flux Frad emergent from the shock
wave was found to be independent of the lower limit nu_L of the frequency range
provided that nu_L < nu_2, where nu_2 is the Balmer continuum head frequency,
At the same time the decrease of nu_L is accompanied by decrease of the Lyman
continuum flux and leads to smaller heating and weaker ionization of the
hydrogen gas in the radiative precursor. For all models the size of the
radiative precursor is of 10^4 cm and corresponds to several mean free paths of
photons at the frequency of the Lyman continuum edge nu_1. The compression
ratio at the discontinuous jump gradually increases with increasing upstream
velocity U_1, reaches the maximum of \rho^+/\rho^- = 3.62 at U_1 = 55 km/s and
slowly decreases for larger U_1 due to the strong rize of the preshock gas
temperature. The radiative flux from the shock wave was determined as a
function of the upstream velocity U_1 and its ratio to the total energy flux in
the shock wave C_2 was found to range within 0.18 < Frad/C_2 < 0.92 for 15 km/s
<= U_1 <= 65 km/s. Thus, at upstream velocities U_1 > 60 km/s the shock wave
losses more than 90% of its total energy due to radiation. For all shock wave
models the role of collisional processes in both bound-bound and bound-free
atomic transitions was found to be negligible in comparison with corresponding
radiative processes.
