**4. Antenna states and processes**

Antenna states of atomic particles or their groups are the states between them resulting from the reemission of photons without work production and heat dissipation. Below is shown that а comparison of the efficiencies of the reversible and irreversible photon reemissions occuring in parallel made it clear that it is impossible to attain very high efficiencies in the conversion of solar heat into work without the reversible photon reemissions as antenna process.
