Survey of H 3 Transitions between 3000 and 4200 cm

Most of a large gap in the laboratory rovibrational spectrum of H 3 between the ν 2 fundamental and the first overtone has been filled using a recently automated color center laser spectrometer which scans between 3000 and 4200 cm. A narrow-bore liquid-nitrogen-cooled He/H 2 discharge is used to produce rotationally and vibrationally hot H 3 . With the high-temperature plasma and the improved sensitivity of the spectrometer we were able to probe very high-energy rovibrational levels, several in the region of the barrier to linearity where theoretical calculations are expected to break down.