Determination of the electric dipole moment of KrH +

Abstract

By measuring the isotope shifts of the rotational g R-factors of different isotopic species the electric dipole moment of the molecular ion KrH + was determined. For that purpose we studied the Zeeman effect of the J = 1 ← 0 transition of KrH + at 494.5 GHz and the J = 2 ← 1 transition of KrD + at 503 GHz. In a magnetic field of 4.950 T the rotational transition splits into two Δ M = ±1 components, resulting in splittings of approximately 41.8 MHz (KrH +) and 21.1 MHz (KrD +). It turned out that there is a major influence of the zero-point vibrations on the experimentally determined electric dipole moment, which results in an uncertainty of the interpretation of the experimental data. The ions were generated in a modified anomalous discharge placed in a superconducting magnet. The transitions were observed by direct absorption of the harmonics of a 70-GHz klystron, using the tunable FIR sideband spectrometer at Nijmegen university.