Laboratory experiments and chemical models

NANOCOSMOS has developed a custom-designed vacuum chamber for the study of gas-phase molecular species through rotational spectroscopy. The innovative breakthrough is the coupling of the chamber to the new NANOCOSMOS millimeter broad band receivers. These receivers are twins of those built for the Yebes 40 meter radio telescope. We call the whole experimental setup as GACELA – Gas Cell for Laboratory Astrophysics.

Our experiments address the characterization of molecules that represent a considerable fraction of all the molecular species detected in the interstellar medium – ISM – but present rotational parameters not precise enough to allow their detection in the ISM. Therefore, we have used GACELA to measure the rotational spectrum of 4 molecular species in the frequency ranges 31.5–50 GHz (Q band) and 72–116.5 GHz (W band) in the laboratory. At the same time, we support these spectroscopic studies with high-level ab initio calculations. Finally, we use the derived experimental rotational parameters to allow the search of these molecular species in astrophysical environments.

We have complemented the GACELA experiments with other techniques like Fourier transform microwave (FTMW) spectroscopy at UVA (11 molecular compounds), absorption spectroscopy (2 molecular compounds) and cryogenic trapping machine experiments (7 protonated molecular species).

Below, we show a summary table on the performed experimental characterizations and techniques. We also include the Nanocosmos publication when clicking on the compound. For Polycyclic aromatic hydrocarbons (PAHs), proceed far below after the table (new page).

Gas cell for Laboratory Astrophysics (GACELA)

The Gas Cell for Laboratory Astrophysics (GACELA) consists of a stainless-steel chamber 1 meter long and a diameter of 60 cm. It is equipped with two teflon windows that allows the study of gases through rotational spectroscopy inside the chamber.

Hence, the team coupled the new NANOCOSMOS millimeter broad band receivers into the setup. These receivers are twins of those built for the Yebes 40 meter radio telescope. A series of vacuum chamber ports allow the injection of gas and liquids to perform plasma generation, ultraviolet photochemistry and optical spectroscopy. GACELA was built at the Segainvex Laboratories located at the Universidad Autónoma de Madrid.

Outstanding publications on our experimetal setup:

1) Broad-band high-resolution rotational spectroscopy for laboratory astrophysics  (J. Cernicharo, J. D. Gallego, J. A. López-Pérez, and 32 co-authors). Astronomy & Astrophysics, 2019 June; 626, A34. Published online 2019, June 7.

2) Using radio astronomical receivers for molecular spectroscopic characterization in astrochemical laboratory simulations: A proof of concept (I. Tanarro, B. Alemán, P. de Vicente, and 26 co-authors). Astronomy & Astrophysics, 2018 Jan; 609: A15. Published online 2017 Dec 22.

GACELA addresses an innovative potential to perform novel experiments on plasma physics, photochemistry and ices. We also address the spectroscopical characterization of a gas injected in the cell. Thus, we performed a first set of experiments in February 2018 with the detection of CH3CN in a few seconds with a very high signal-to-noise ratio (S/N). The whole system was further improved and we have made multiple runs in the full-experimental phase from May 2018.

Check our posts on the GACELA setup