Rydberg states of triatomic hydrogen and deuterium

The triatomic hydrogen ion (H$_3^+$) has spurred tremendous interest in astrophysics in recent decades, and Rydberg states of H$_3$ have also maintained an important role for understanding H$_3^+$ experiments. In a previous study [J. Chem. Phys. \textbf{133}, 234302 (2010)], radiative transitions between neutral H$_3$ Rydberg states were calculated at wavelengths near 7 microns, and could be compared with mid-infrared laser lines observed in hydrogen/rare gas discharges. The present study extends the investigation to wavelengths near 10 -- 13 microns. Rydberg states of D$_3$ are also treated.