H3 plays a key role in interstellar chemistry as the initiator of ion–molecule chemistry. The amount of H3 observed in dense interstellar clouds is consistent with expectations, but the large abundance of H3 seen in diffuse clouds is not easily explained by simple chemical models. A crucial parameter in predicting the abundance of H3 in diffuse clouds is the rate constant for dissociative recom...

A fundamental problem in astrochemistry concerns the synthesis and survival of complex organic molecules (COMs) throughout the process of star and planet formation. While it is generally accepted that most complex molecules and prebiotic species form in the solid phase on icy grain particles, a complete understanding of the formation pathways is still largely lacking. To take full advantage of ...

Rotational excitation of interstellar PN molecules induced by collisions with H2 is investigated. We present the first ab initio four-dimensional potential energy surface (PES) for PN–H2 van der Waals system. The PES was obtained using an explicitly correlated coupled cluster approach single, double, and perturbative triple excitations [CCSD(T)-F12b]. method interpolating moving least squares u...

The formation routes of two structural isomers—propenal (C2H3CHO) and cyclopropanone (c-C3H4O)—were investigated experimentally by exposing ices of astrophysical interest to energetic electrons at 5.5 K thus mimicking the interaction of ionizing radiation with interstellar ices in cold molecular clouds. The radiationinduced processing of these ices was monitored online and in situ via Fourier T...

The discovery and synthesis of fullerenes led to the hypothesis that they may be present and stable in interstellar space. As first evidence for the largest molecule ever detected in space, we have recently detected two new diffuse interstellar bands (DIBs) in the near-infrared that are consistent with laboratory measurements of the C 60 cation. The inferred abundance (up to 0.9 % of cosmic car...

In this chapter we describe how elements have been and are still being formed in the galaxy and how they are transformed into the reservoir of materials present in protostellar environments. We discuss the global cycle of matter from stars, where nucleosynthesis produces heavy elements that are ejected through explosions and winds into the interstellar medium (ISM), through the formation and ev...

The carriers of the diffuse interstellar bands (DIBs) is one of the longest standing problems in astronomical spectroscopy. This completely unattributed absorption spectrum stretches from the UV to near-IR and can be seen in multiple interstellar sightlines with the strongest features at 443 nm and 578 nm. Additionally, the number of known features grows with every observation. No known molecul...