Magnetic field induced rotation of the polarization plane of hydroxyl radical free induction decay in the terahertz region

Abstract

Effect of the external longitudinal magnetic field on the optical free induction decay (FID) of the hydroxyl radical was investigated in detail. The experiments were performed on a rotational transition of OH (2Π3/2(J = 5/2) ← 2Π3/2(J = 3/2) at 83.8 cm−1) using the terahertz free electron laser. The rotation of the plane of polarization of FID as a function of time after the excitation of the radical was measured for various magnetic fields. The effect of nonmonotonic rotation of FID polarization plane in magnetic field was experimentally discovered. Numerical simulation of FID of the hydroxyl radical in a magnetic field has been carried out.