Comprehensive evaluation and compilation of H3+ spectroscopy

Since its initial detection in 1980, there have been 17 laboratory studies of the H-3(+) infrared spectrum, reporting 895 transition.,, from a variety of fundamental, overtone, combination, and hot bands, The results of these two decades of labor, however, are difficult to utilize. There is no comprehensive list of the observed H-3(+) transitions, and the literature contains errors in frequency measurement and assignment due to the inherent difficult of the measurements and the complexity of the spectrum. This paper resolves these problems while assembling all of the data into a single source. We have reviewed all reported transitions of H-3(+) for reliability in frequency measurement and have reassigned them based on a comparison with recent theoretical calculations. We have also developed a complete labeling scheme for all energy levels below 9000 cm(-1), which alleviates the confusion in assigning H-3(+) transitions that results from the difficulty of labeling the rovibrational energy levels of a molecule with such strong mixing. Our comprehensive linelist was then used to produce a set of 526 experimentally determined energy levels, which facilitates direct comparison with theoretical calculations and prediction of the "forbidden" pure rotation spectrum Of H-3(+). (C) 2001 Elsevier Science.