The International Astrophysics Network was established in 1994. It presents a very powerful research association to predict the formation and actually detect hitherto unobserved molecules in extraterrestrial environments based on cutting-edge laboratory crossed beams and surface scattering experiments combined with electronic structure theory, statistical calculations, and kinetic models. The prime directive of this network is to unravel the underlying dynamics and reaction mechanisms on how complex, (astrobiologically) important molecules are synthesized from the bottom up via single atoms, radicals, and small molecules in the interstellar medium, in atmospheres of planets and their satellites, in cometary comae, as well as in extraterrestrial ices. This research holds also strong links to combustion processes, chemical vapor deposition, non- classical organic and organo-metallic chemistry, and to atmospheric chemistry.

Our network is organized as follows. The experiments involve reactive scattering studies and employ a novel crossed beams machine (gas phase chemistry; Kaiser), a recently commissioned gas phase photodissociation machine (Stranges), and gas-surface scattering setups (Kaiser/Mason). Both ‘gas phase’ machines investigate how molecules are formed (crossed beams) and destroyed (photolysis) in the interstellar medium, planetary atmospheres, and combustion processes. The surface scattering experiments untangle the interaction of extraterrestrial ices , carbonaceous surfaces, and minerals with charged particles, UV/VUV photons, and atoms.

All experiments are pooled together with electronic structure calculations and computations of rate constants to verify elucidated reaction mechanisms theoretically in collaboration with Bettinger, Head-Gordon, Schleyer, Schaefer, Mebel, Hanacchi, and Osamura. The potential energy surfaces will be utilized also to perform dynamics calculations, which will in turn be compared to the experimental data to bridge the theoretical understanding of reactive scattering of complex systems with actual experiments.

These data (rate constants, branching ratios, reaction products and intermediates) are then incorporated in collaboration with Herbst into  reaction networks modeling the evolution of interstellar environments (cold molecular clouds, circumstellar envelopes, star forming regions). Very recently, a collaboration was also established with Howard, Richter, and Green to incorporate these results also into cutting-edge combustion chemistry networks. Since the laboratory experiments predict further the existence of hitherto unobserved molecules in the interstellar medium and in planetary atmospheres, these species will be searched for in those environments in collaboration with Turner and Chin.

The spectroscopic transitions necessary to carry out the astronomical observations are either taken from databases, are going to be computed, and will be determined experimentally (optical and ultraviolet) in collaboration with Salama. Note that the proposed experiments also assist an analyses of current and prospective data of in situ analyses of planetary and satellite atmospheres via space probes (Cassini-Huygens; Deep Impact; Neptune Orbiter; Pluto Express) and remote sensing spectroscopic observations with telescopes (Stratospheric Observatory for Far Infrared Astronomy; Space Infrared Telescope Facility).

This synergistic approach combines sophisticated laboratory experiments, electronic structure theory, statistical and quasi classical trajectory calculations, kinetic models, and actual astronomical observations to address generalized concepts in understanding the dynamics of elementary atom-radical and radical-radical reactions in combustion processes and in extraterrestrial environments systematically. The unique power of this network to predict and actually find hitherto unobserved molecules in astronomical environments was demonstrated explicitly in the first astronomical detection of cyanoallene towards the Orion Molecular Cloud employing the 100 m telescope in Effelsberg (Germany) and the 15 m dish at SEST (Chile) (Chin, Kaiser). The search for interstellar cyanobenzene is currently in progress.

astrochemistry network

Network Members

Holger F. Bettinger
University of Bochum (Germany)
Yinan Chin
Tamkang University (Taiwan)
William H. Green
Yacine Hannachi
University of Bordeaux (France)
Martin Head-Gordon
University of California at Berkeley (USA)
Eric Herbst
Ohio State University (USA)
Jack B. Howard
Nigel Mason
The Open University (UK)
Alexander M. Mebel
IAMS (Taiwan)
Yoshihiro Osamura
Rikkyo University (Japan)
Henning Richter
Farid Salama
Henry F. Schaefer
Paul v. R. Schleyer
University of Georgia (USA)
Domenico Stranges
University La Sapienza (Italy)
Barry Turner