Stability of relaxation processes in a quantum system as a main factor for achieving the high long-term frequency stability of a standard

The processes of synchronous Zeeman´s relaxation are investigated with simultaneous observing population difference, M_z (τ₁) - and coherence, M_x (τ₂), - components within a spin of system of ⁸⁷Rb atoms in cells with antirelaxation coating, when changing cell volume, operating temperature and pumping light intensity with D₁ - line. The existence of total relaxation `degeneracy´ is experimentally determined which is characterized through (τ₁ ≈ τ₂) - condition being necessary for achieving a high long-term frequency stability of standards (in particular, quantum magnetometers). The procedure for investigating relaxation processes developed by the author could be useful for the realization of atomic frequency standards with a high long-term frequency stability.