Communication: Visible Line Intensities Of The Triatomic Hydrogen Ion From Experiment And Theory

The visible spectrum of H-3(+) is studied using high-sensitivity action spectroscopy in a cryogenic radiofrequency multipole trap. Advances are made to measure the weak ro-vibrational transitions from the lowest rotational states of H-3(+) up to high excitation energies providing visible line intensities and, after normalisation to an infrared calibration line, the corresponding Einstein B coefficients. Ab initio predictions for the Einstein B coefficients are obtained from a highly precise dipole moment surface of H-3(+) and found to be in excellent agreement, even in the region where states have been classified as chaotic. (c) 2014 AIP Publishing LLC.