A computed line list for the H2D+ molecular ion

TL;DR

This paper presents a comprehensive and validated computed line list for H2D+ with over 22 million transitions, useful for high-temperature astrophysical applications and spectral modeling.

Contribution

It provides the first extensive, high-accuracy line list for H2D+ covering a wide frequency range and temperature applicability, validated through consistency checks.

Findings

Line list contains over 22 million transitions.

Valid for temperatures up to 3000 K.

Includes synthetic spectra and partition functions.

Abstract

A comprehensive, calculated line list of frequencies and transition probabilities for the singly deuterated isotopologue of H3+, H2D+, is presented. The line list, called ST1, contains over 22 million rotational-vibrational transitions occurring between more than 33 thousand energy levels; it covers frequencies up to 18500 cm-1. All energy levels with rotational quantum number, J, up to 20 are considered, making the line list useful for temperatures up to at least 3000 K. About 15% of these levels are fully assigned with approximate rotational and vibrational quantum numbers. The list is calculated using a previously proposed, high accuracy, ab initio model and consistency checks are carried out to test and validate the results. These checks confirm the accuracy of the list. A temperature-dependent partition function, valid over a more extended temperature range than those previously published, and cooling function are presented. Temperature-dependent synthetic spectra in the frequency range 0 - 10000 cm-1 are also given.