Astrochemistry is one of the scientific frontiers in which many intriguing open questions remain that directly and indirectly impact our lives, and thus, it garners significant attention. These open questions revolve around the origins of life and the complex chemistry occurring in astronomical systems, and the resulting research indirectly influences our lives through the innovation that occurs. We aimed to help understand the complex chemistry occurring the interstellar medium (ISM) by using electrical discharge sources with rotational spectroscopy to study sulfur and metal containing molecules and polycyclic aromatic hydrocarbons (PAHs). While there is evidence that these species exist in the ISM, especially molecules containing sulfur, astronomers have been unable to detect more complex species bearing sulfur and metals. It is possible that these species could be found on ice grains and not in the gas phase; however, they could then be released into the gas phase so that we can detect them with radio telescopes. Also, PAHs are thought to have been a source of sequestered carbon; however, until recently, direct evidence by the individual identification of a PAH had not been able to prove their existence. Then in 2021 indene was detected, followed by the detections of the substituted PAHs, cyano-naphthalene and cyano-indene were made. We now know that these PAHs exist in the ISM, but we do not know to what extent. Thus, our research aimed to help answer the questions: Where is sulfur being sequestered?, Why are we not detecting more and bigger sulfur containing species?, and What other species of PAHs can we detect?
We aimed to answer these questions through the following objectives. First, we implemented a discharge source and laser ablation in the existing broadband rotational spectrometer at the University of Valladolid to produce new sulfur/metal bearing species and PAHs. With rotational spectroscopy, we can generate accurate line lists and obtain rotational parameters that help guide astronomers in their searches for new molecular species. We then developed a controlled reactive chemistry source that enabled us to engineer chemical reactions so that we may explain the chemistry that is occurring in the formation of new molecular species. With this we provide a new tool not only for the astrochemistry community but also for the atmospheric chemistry community. Finally, we set out to detect these species in astronomical datasets through international collaborations using state-of-the-art astronomical surveys.
