THE DESCRIPTION OF THE MULTIQUANTUM EFFECTS IN ELECTRON-PARAMAGNETIC-RESONANCE-SPECTROSCOPY USING THE BLOCH-EQUATION

The Bloch equations are applied to describe the response of the two-le vel system, irradiated with bichromatic microwave field under conditio n of electron paramagnetic resonance in the wide range of saturation c ondition and relaxation times. The generation of I:he intermodulation effects in such systems has been demonstrated. Numerical procedures of solving a set of stiff, nonlinear differential equations are applied. The line shapes of the generated signals have been simulated for diff erent microwave amplitudes and relaxation rates. The dependence of the intermodulation signals on omega(2) -omega(1), the frequency differen ce between two incident microwave: fields, is studied. The influence o f a significant saturation factor on this dependence is demonstrated a nd explained. Then an estimation of the relaxation rates from the inte rmodulation sidebands is examined on the basis of the classical model. In the case when the frequency separation between two alternating fie lds is less than relaxation rates, analytical formulas for the intermo dulation signals have been found. (C) 1998 American Institute of Physi cs.