A two-way electron paramagnetic resonance cavity for magnetic dipole transition (MDT) and electric dipole transition (EDT) was manufactured. There are two openings to fit the sample cell for MDT and for EDT in the cylindrical TE011 mode. One opening is located on the axis of the cavity and the other is located away from the axis. EPR spectra obtained from the mixture of oxygen and nitrogen oxide when the sample cell was inserted in each opening showed the selective transition of the MDT or of the EDT of the species. When de electric field parallel to the steady magnetic field was applied to the nitrogen oxide located away from the axis, each of the EDT peaks was divided into two peaks, one of which was higher than the other. The magnitude of the splitting was proportional to the electric field strength, in agreement with the theory. The permanent electric dipole moment 0.159 × 10−18 cgs esu obtained agreed with the value reported in the literature.
Isao Suzuki and Yoshihisa Kaneko, "Two-Way Electron Paramagnetic Resonance (EPR) Cavity and Stark Effect on Nitrogen Oxide," Appl. Spectrosc. 34, 296-299 (1980)