  A resonance-induced change in the resistivity of the surface state electrons
(SSE) exposed to the microwave (MW) radiation is observed. The MW frequency
corresponds to the transition energy between two lowest Rydberg energy levels.
All measurements are done with electrons over liquid 3He in a temperature range
0.45-0.65 K, in which the electron relaxation time and the MW absorption
linewidth are determined by collisions with helium vapor atoms. The input MW
power is varied by two orders of magnitude, and the resistivity is always found
to increase. This effect is attributed to the heating of electrons with the
resonance MW radiation. The temperature and the momentum relaxation rate of the
hot electrons are calculated as a function of the MW power in the cell, and the
Rabi frequency is determined from the comparison of the theoretical result with
the experiment. In addition, the broadening of the absorption signal caused by
the heating is studied experimentally, and the results are found to be in good
agreement with our calculations.
