Improved determination of the 1(0)-0(0) rotational frequency of NH3D+ from the high resolution spectrum of the v4 infrared band

TL;DR

This study precisely measures the v4 infrared band spectrum of NH3D+ to accurately determine its rotational transition frequency, aiding astronomical line identification.

Contribution

The paper provides a highly accurate rotational frequency for NH3D+ derived from high-resolution spectroscopy, improving previous estimates and supporting astronomical line assignments.

Findings

Derived rotational frequency: 262817(6) MHz

Supports identification of NH3D+ in space

Enhanced spectral data accuracy

Abstract

The high resolution spectrum of the v4 band of NH3D+ has been measured by difference frequency IR laser spectroscopy in a multipass hollow cathode discharge cell. From the set of molecular constants obtained from the analysis of the spectrum, a value of 262817(6) MHz (3sigma) has been derived for the frequency of the 1(0)-0(0) rotational transition. This value supports the assignment to NH3D+ of lines at 262816.7 MHz recorded in radio astronomy observations in Orion-IRc2 and the cold prestellar core B1-bS.