  The emission from dark ages halos in the lines of transitions between lowest
rotational levels of hydrogen and hydrogen deuteride molecules is analyzed. It
is assumed molecules to be excited by CMB and collisions with hydrogen atoms.
The physical parameters of halos and number density of molecules are
precalculated in assumption that halos are homogeneous top-hat spheres formed
from the cosmological density perturbations in the four-component Universe with
post-Planck cosmological parameters. The differential brightness temperatures
and differential spectral fluxes in the rotational lines of H$_2$-HD molecules
are computed for two phenomena: thermal luminescence and resonant scattering of
CMB radiation. The results show that expected maximal values of differential
brightness temperature of warm halos ($T_K\sim$200-800 K) are at the level of
nanokelvins, are comparable for both phenomena, and are below sensitivity of
modern sub-millimeter radio telescopes. For hot halos ($T_K\sim$2000-5000 K)
the thermal emission of H2-ortho molecules dominates and the differential
brightness temperatures are predicted to be of a few microkelvins at the
frequencies 300-600 GHz, that could be detectable with telescopes of a new
generation.
