  It is shown that passive gravitational mass operator of a hydrogen atom in
the post-Newtonian approximation of the general relativity does not commute
with its energy operator, taken in the absence of gravitational field.
Nevertheless, the equivalence between the expectation values of passive
gravitational mass and energy is shown to survive at a macroscopic level for
stationary quantum states. Breakdown of the equivalence between passive
gravitational mass and energy at a microscopic level for stationary quantum
states can be experimentally detected by studying unusual electromagnetic
radiation, emitted by the atoms, supported and moved in the Earth gravitational
field with constant velocity using spacecraft or satellite.
