Methanol is ubiquitous in star-forming regions, and has recently been detected in a protoplanetary disk. Astrochemical models have shown that methanol photolysis contributes to complex organic chemistry in interstellar ices. While some methanol photolysis branching ratios have been measured, infrared condensed-phase measurements rely on assumptions about the chemistry, and mass spectrometric measurements cannot distinguish structural isomers. To address these challenges, we are using pure rotational spectroscopy to quantitatively probe the methanol photolysis products. We use a VUV laser to dissociate methanol in the throat of a supersonic expansion, and probe the products downstream after cooling is complete. We then use a rotational diagram analysis to determine the relative density of each product relative to methanol. We have detected the methoxy, hydroxymethyl, and formaldehyde photolysis products. We present here the experimental setup and the initial results and discuss these results in the context of interstellar chemistry.

Microwave-millimeter/submillimeter wave double-resonance spectroscopy has been developed with the use of technology typically employed in chirped pulse Fourier transform microwave spectroscopy and fast-sweep direct absorption (sub)millimeter-wave spectroscopy. This technique offers the high sensitivity provided by millimeter/submillimeter fast-sweep techniques with the rapid data acquisition offered by chirped pulse Fourier transform microwave spectrometers. Rather than detecting the movement of population as is observed in a traditional double-resonance experiment, instead we detected the splitting of spectral lines arising from the AC Stark effect. This new technique will prove invaluable when assigning complicated rotational spectra of complex molecules. The experimental design is presented along with the results from the double-resonance spectra of methanol as a proof-of-concept for this technique.

O(1 D) insertion reactions with stable precursors have proved an efficient way of producing important prebiotic molecules that are highly reactive and otherwise unstable under laboratory conditions. In 2015, Hays et al. b reported successful production of gaseous methanol and vinyl alcohol by exothermic O(1 D) insertion into methane and ethylene, respectively, and collected their rotational spectra in the millimeter/submillimeter region. Prior to this, in 2013 Hays et al. c reported a computational study predicting the formation of methanediol, methoxymethanol and aminomethanol, through O(1 D) insertion into methanol, dimethyl ether and methylamine, respectively. These species are all important prebiotic molecules and have been shown to be stable under interstellar conditions. We therefore seek to collect their spectra for comparison to interstellar observations. Here we will report experimental progress toward producing and characterizing the spectra of aminomethanol and methanediol using O(1 D) insertion reactions and millimeter/submillimeter spectroscopy.

Methanol is one of the most abundant and important molecules in the interstellar medium, playing a key role in driving more complex organic chemistry both on grain surfaces and through gas-phase ion-molecule reactions. Methanol photolysis produces many radicals such as hydroxyl, methoxy, hydroxymethyl, and methyl that may serve as the building blocks for more complex organic chemistry in star-forming regions. The branching ratios for methanol photolysis may govern the relative abundances of many of the more complex species already detected in these environments. However, no direct, comprehensive, quantitative measurement of methanol photolysis branching ratios is available. Using a 193 nm excimer laser, the gas phase photolysis of methanol was studied in the (sub)millimeter range, where the rotational spectroscopic signatures of the photolysis products were probed. Here we present preliminary results from this experiment.

Aminomethanol (HOCH 2 NH 2) is a molecule of astrochemical interest as it is thought to be the precursor to the simplest amino acid, glycine. To date, no laboratory spectrum has been recorded because it is unstable under normal laboratory conditions. As a result, a millimeter spectrometer was developed to study the products of O(1 D) insertion into methylamine, with the goal of producing aminomethanol. Here we present the results of this study, including other observed reaction products and a preliminary assignment of aminomethanol.