The possibility of positronium detection at radio wavelengths is investigated in detail. For orthopositronium, the fine structure lines of the n = 2 level (1.62 cm, 2.30 cm and 3.48 cm) may be probably detected by radiotelescopes of next generations with the sensitivity around 1 microJansky. The spin-flip line of the ground state (0.147 cm) may be observed from sources with a narrow annihilation line by modern telescopes with the sensitivity around 10 microJansky. In the fine structure and spin-flip lines a maser effect is produced. The expected radio fluxes in the spin-flip line can reach detected limits for certain source geometries and optimal physical conditions inside the source.
@article{arxiv.astro-ph/9912550,
title = {Space Positronium Detection by Radio Measurements},
author = {V. Burdyuzha and Ph. Durouchoux and V. Kauts},
journal= {arXiv preprint arXiv:astro-ph/9912550},
year = {2007}
}