Communication: Magnetic dipole transitions in the OH A 2Σ + ← X 2Π system

Abstract

We report on the observation of magnetic dipole allowed transitions in the well-characterized A 2Σ + - X 2Π band system of the OH radical. A Stark decelerator in combination with microwave Rabi spectroscopy is used to control the populations in selected hyperfine levels of both Λ-doublet components of the X 2Π 32, v 0, J 32 ground state. Theoretical calculations presented in this Communication predict that the magnetic dipole transitions in the A 2Σ +, v 1 ← X 2Π, v 0 band are weaker than the electric dipole transitions by a factor of 2.58 × 10 3 only, i.e., much less than commonly believed. Our experimental data confirm this prediction. © 2012 American Institute of Physics.