title: 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 (2)Σ(+) - X (2)Π 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 (2)Π(3/2), v = 0, J = 3/2 ground state. Theoretical calculations presented in this Communication predict that the magnetic dipole transitions in the A (2)Σ(+), v = 1 ← X (2)Π, 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.
authors.affiliation: Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Kirste
authors.forename: Xingan
authors.initials: X
authors.lastname: Wang
authors.forename: Gerard
authors.initials: G
authors.lastname: Meijer
authors.forename: Koos B
authors.initials: KB
authors.lastname: Gubbels
authors.forename: Ad
authors.initials: A
authors.lastname: van der Avoird
authors.forename: Gerrit C
authors.initials: GC
authors.lastname: Groenenboom
authors.forename: Sebastiaan Y T
authors.initials: SY
authors.lastname: van de Meerakker