The High Resolution Infrared Spectrum of HCl. Astrophys J Lett 2016;833:L32. [PMID: 28261442 PMCID: PMC5331965 DOI: 10.3847/2041-8213/833/2/l32]

Broad band high resolution rotational spectroscopy for Laboratory Astrophysics

We present a new experimental setup devoted to the study of gas phase molecules and processes using broad band high spectral resolution rotational spectroscopy. A reactor chamber has been equipped with radio receivers similar to those used by radio astronomers to search for molecular emission in space. The whole Q (31.5-50 GHz) and W bands (72-116.5 GHz) are available for rotational spectroscopy observations. The receivers are equipped with 16×2.5 GHz Fast Fourier Transform spectrometers with a spectral resolution of 38.14 kHz allowing the simultaneous observation of the complete Q band and one third of the W band. The whole W band can be observed in three settings in which the Q band is always observed. Species such as CH3CN, OCS, and SO2 are detected, together with many of their isotopologues and vibrationally excited states, in very short observing times. The system permits automatic overnight observations and integration times as long as 2.4×105 seconds have been reached. The chamber is equipped with a radiofrequency source to produce cold plasmas and with four ultraviolet lamps to study photochemical processes. Plasmas of CH4, N2, CH3CN, NH3, O2, and H2, among other species, have been generated and the molecular products easily identified by their rotational spectrum, and mass spectrometry and optical spectroscopy. Finally, the rotational spectrum of the lowest energy conformer of CH3CH2NHCHO (N-Ethylformamide), a molecule previously characterized in microwave rotational spectroscopy, has been measured up to 116.5 GHz allowing the accurate determination of its rotational and distortion constants and its search in space.

First Laboratory Detection of Vibration-Rotation Transitions of 12CH+ and 13CH+ and Improved Measurement of their Rotational Transition Frequencies

The long-searched C-H stretches of the fundamental ions CH+ and 13CH+ have been observed for the first time in the laboratory. For this, the state-dependent attachment of He atoms to these ions at cryogenic temperatures has been exploited to obtain high-resolution rovibrational data. In addition, the lowest rotational transitions of CH+, 13CH+ and CD+ have been revisited and their rest frequency values improved substantially.

Accurate Frequency Determination of Vibration-Rotation and Rotational Transitions of SiH. THE ASTROPHYSICAL JOURNAL 2017;849:60. [PMID: 29142330 PMCID: PMC5683345 DOI: 10.3847/1538-4357/aa8fca]

The fundamental 28SiH+ ion has been characterized in a collaborative work, utilizing a hollow-cathode-discharge laser-spectrometer and a cryogenic ion trap spectrometer. Twenty-three vibration-rotation transitions around 4.75 μm have been detected with high accuracy. This has facilitated the first direct measurement of the pure rotational transition J = 1 ← 0 at 453056.3632(4) MHz in the trap spectrometer. The measured and accurately predicted transitions enable the search for this ion in space with IR and sub-mm telescopes.