Rydberg states of triatomic hydrogen and deuterium

TL;DR

This paper investigates Rydberg states of triatomic hydrogen and deuterium, extending previous calculations to longer wavelengths, which are relevant for astrophysical and laboratory observations.

Contribution

It provides new calculations of Rydberg states of H$_3$ and D$_3$ at wavelengths near 10-13 microns, expanding understanding of their spectral properties.

Findings

Calculated Rydberg transition wavelengths near 10-13 microns.

Extended previous work on H$_3$ Rydberg states to longer wavelengths.

Included D$_3$ Rydberg states in the analysis.

Abstract

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.