Laboratory spectroscopy of H-3(+)

The experimental, determination of the low-lying rovibrational energy level s of H-3(+) using high-resolution, high-sensitivity infrared laser spectros copy has confirmed this ion's equilateral triangle equilibrium geometry, pr ovided direct information on its quantum mechanical characteristics, and en abled its extensive study in planetary ionospheres and in the interstellar medium. Since the discovery of the nu(2) <-- 0 fundamental band, the laboratory spe ctroscopy of H-3(+) has been pushed to higher energies through the study of vibrational hot bands, overtones, forbidden bands and combination bands. W e review the 20 years of laboratory spectroscopy of this important ion, dis cuss our recent work on the nu(1) + 2 nu(2)(2) <-- 0 and 2 nu(1) + nu(2) <- - 0 bands, and examine the prospects for the future of H-3(+) spectroscopy.