Brief Introduction to H₃⁺

Royal Society Discussion Meeting

Spectroscopic Databases

Online Intensity Calculator

Links to H₃⁺ Related Sites

Since the initial detection of its infrared spectrum in 1980, there have been 18 laboratory studies of the H₃⁺ spectrum, reporting approximately 900 transitions from a variety of fundamental, overtone, combination, and hot bands. Recently (C. M. Lindsay and B. J. McCall, J. Mol. Spectrosc. 210, 60-83 (2001)), the results of these two decades of labor have been carefully re-evaluated and compiled into a database of experimental transitions. In that work, every reported transition of H₃⁺ was reviewed for reliability in frequency measurement (and uncertainty) and was reassigned based on a comparison with the most accurate theoretical calculations available. Additionally, a complete labeling scheme was developed for all energy levels below 9000 cm^-1, which alleviated the confusion in assigning H₃⁺ transitions that results from the difficulty of labeling the ro-vibrational energy levels of a molecule with such strong mixing. This comprehensive linelist was then used to produce a set of ~500 experimentally determined energy levels, which facilitates a direct comparison with theoretical calculations and the prediction of the "forbidden'' pure rotation spectrum of H₃⁺.

Below are the electronic versions of the transition and energy data. These databases will corrected should any errors be identified in the future and updated to include additional experimental data as it becomes available. Below the database links is a history of the database, keeping track of changes made to either of them. Figures and other supplemental material pertaining to this study is available here.

Here are the databases: