After recombination of hydrogen the one of probable mechanism of formation CMBR fluctuations there can be a scattering by small density inhomogeneities if they have peculiar velocities and opacity for electromagnetic emission. Peculiar velocities of various spatial scale are predicted in all models of evolution.
At the same time, opacity can be caused by the various reasons. At a stage, when temperature of matter and radiation becomes less 500 - 600 K, opacity can arise as a result of scattering in molecule lines, if there were various chemical elements, namely: He, D, Li, C, N, O.
In all these cases is shown essential feature of fluctuations - very strong frequency dependence of effect. Search of spectral-spatial fluctuations of cosmic background emission was carried out with south sector of a radio telescope RATAN-600 at wavelength 6.2 cm in April 1999, February 2000 and February 2001.
For increase the time of accumulation of a signal with our antenna the drift curves near celestial poles were used at declination +89.5 . Width of the diagram of the antenna at this height was 45" х 7', so the source passed horizontal diagram during 343 seconds, that increase a sensitivity more, than 10 times.
For study of the signal spatial characteristics in each channel of spectrometer power spectrum of fluctuations were calculated (squares of amplitudes) on a right ascension with the help of the FFT code.
The measured spectra of spatial fluctuations look completely flat. The irregularity of spectra however is appreciable in the spatial periods about 4' (physical period on record - 32 minutes).
The irregularity is not random, because not only proves by observation in two different cycles, but also disappears on a spectrum of difference of signal or at connection instead of antenna the cold matched load.
Comparison of amplitude of an observable spectral detail with modelling spectra of artificial sine wave signal mixed with observable of noise signal, has shown, that it has approximately 0.003 K antenna temperature, that is three times more than root mean square noise fluctuations, and, on the other hand, - about 10^-3 from delta Т/Т.
For the first rotational line of a molecule LiH at angular scale 4' we have the linear size of protoobject L approximately 180 kpc, that corresponds to it mass approximately 10¹⁴ Mo. Taking the appropriate constants for optical thickness and assuming that peculiar velocity is about 60 km/s, we obtain an estimate of an abundance of these molecules less than 3 x 10¹⁴.
This estimate approximately by 3 order reduces a range of estimations available in different works and it is quite reasonable from the point of view kinetic of molecules in nonequilibrium condition at presence of gradients of velosity and density. However final conclusion about physical conditions in such objects requires more careful investigations.