We present preliminary results of an spectral-line survey at 1, 2, and 3 mm of the galactic center cloud Sgr B2(N). With the current data, several simple prebiotic molecules have been conclusively identified, while several more complex molecules have not. When complete, this survey will provide an accurate database of the gas-phase organic inventory in Sgr B2(N).

We present a new gas-grain chemical model that allows the grain-surface formation of saturated, complex, organic species from their constituent functional-groups–basic building blocks that derive from the cosmic ray-induced photodissociation of the granular ice mantles. The surface mobility of the funtional-group radicals is crucial to the reactions, and much of the formation of complex molecules occurs at the intermediate temperatures (~20–40 K) attained during the warm-up of the hot core. Our model traces the evolution of a large range of detected, and as yet un-detected, complex molecules.

Water maser emission has been detected only toward three planetary nebulae (PNe). In particular, in K3-35, the first PN where water vapor maser emission was detected, the components are located in a torus-like structure with a radius of 85 AU and also at the surprisingly large distance of 5000 AU from the star, in the tips of the bipolar lobes. The existence of these water molecules in PNe is puzzling, probably related to some unknown mechanism shielding them against the ionizing radiation. We report the detection of HCO+ (J = 1 − 0) emission toward K 3-35, that not only suggests that dense molecular gas (~105 cm−3) is present in this PN, but also that this kind of PN can enrich their surroundings with organic molecules.

Filmy-QCC is an organic material synthesized in the laboratory, and it exhibits red photoluminescence (PL). The peak wavelength of the PL ranges from 650 to 690 nm, depending on the mass distribution of polycyclic aromatic hydrocarbon (PAH) molecules, and the emission profile is a good match for that of the extended red emission in the Red Rectangle nebula. The quantum yield of the PL ranges from 0.009 to 0.04. When filmy-QCC is dissolved in cyclohexane, it exhibits blue PL in the wavelength range of 400–500 nm with a quantum yield of 0.12–0.16. The large width of the red PL and the large wavelength difference between the PL of the filmy-QCC as a solid film and in a solution indicate that there is a strong interaction between the components of filmy-QCC. The major components of filmy-QCC are PAHs up to 500 atomic mass units. Our laboratory data suggest that the blue luminescence observed in the Red Rectangle nebula is probably caused by small PAHs in a gaseous state, and the extended red emission is caused by larger PAHs in dust grains.

We present results of the mid-IR spectra decomposition for planetary nebulae and compact H ii regions in our Galaxy and Magellanic Clouds. The striking correlation between the required PAH component with “7.7” μm band shifted to about 7.8 μm and electron densities of the modeled sources allows us to argue that this PAH component may be in fact PAH anions (PAH−).

We report on recent developments in the study of diffuse interstellar bands in the Local Group galaxies. We present preliminary results on the detection of the 5780 Å DIB toward 17 targets in the vicinity of NGC 206 in M31.

Dehydrogenated coronene molecules have been proposed as the carrier of the interstellar UV extinction bump and of some diffuse interstellar bands. To test this hypothesis, we have undertaken a combined a) theoretical and b) experimental work on the subject. a) We use the (time–dependent) density functional theory to study the effect of hydrogenation on the UV absorption cross–section of neutral and ionised coronene molecules. b) For the visible and near–UV, these calculations provide useful guidelines to analyse and interpret the electronic spectra obtained with the PIRENEA experimental set-up dedicated to astrochemistry.

The recent combination of new computational chemistry techniques and high performance computational hardware is allowing unprecedented levels of accuracy in the calculations of physical quantities such as potential energy surfaces and rotational-vibrational spectra. Previous results exist in the literature for the first three most stable conformers of glycine at the aug-cc-pVDZ basis set. In this work, we extend the known results, presenting calculations of the four most stable conformers of glycine using the aug-cc-pVQZ basis set. We compare our calculations to experimental values and show that our current calculations differ by <2% from measured values, much better than results from previous years. When searching for molecules in the Interstellar Medium this small difference suggests that computational methods are becoming well-suited for the task. The natural question to ask is: at what point will the small deviation from experimental values render our computations just as reliable as experiments? We feel that the current results show that we are indeed close to this goal.

We present the results of a systematic analysis of the solid state features identified in the circumstellar environments of a large sample of evolved stars with ISO/SWS and Spitzer/IRS spectroscopy. The sample includes several hundred stars with a wide variety of progenitor masses evolving from the early AGB phase to the PN stage. Our observations are used to propose an evolutionary scheme in which the results obtained can be interpreted as a consequence of the nucleosynthesis processes that take place in this short phase of the stellar evolution, in particular the third dredge-up and hot bottom burning, which in turn are also strongly modulated by the stellar metallicity.

To understand the origin of protein/nucleic acid based life as we know it on Earth, we must “follow” the nitrogen. Because of its unique hydrogen bonding characteristics, nitrogen is the key element in catalytic and/or informational proteins and nucleic acids essential to cell function and reproduction. We present evidence that HCN is the original source of prebiotic protein and nucleobase nitrogen. We also present chemically rational models supporting the radical hypothesis that the polymerization of HCN yields ab initio mundi prebiotic protein and polynucleobase macromolecules of sufficient size and complexity to allow the spontaneous generation of pre-RNA World biopolymers capable of catalysis and information transfer.

A small fraction of primitive meteorites and interplanetary dust particles (IDPs) consists of grains of presolar stardust. These grains have extremely unusual isotopic compositions, relative to all other planetary materials, indicating that they condensed in the outflows and explosions of prior generations of stars (Clayton & Nittler 2004). Identified presolar grain types include silicate, oxide and carbonaceous phases. The latter include graphitic carbon, diamond and SiC. Although many of these phases do not have a direct connection to organic chemistry, this is not true of the graphitic spherules. Many of these, with isotopic compositions indicating an origin in C-rich asymptotic giant branch (AGB) star outflows, have a structure consisting of naonocrystalline cores surrounded by well-graphitized C (Bernatowicz et al. 1996). The cores include isotopically anomalous polycyclic aromatic hydrocarbons (Messenger et al. 1998) and represent a link between molecular chemistry and dust condensation in stellar outflows. Meteorites and IDPs also contain abundant isotopically anomalous organic matter, including distinct organic grains, some of which probably formed in stellar outflows and/or the interstellar medium (ISM) (Busemann et al. 2006, Floss et al. 2004). In some IDPs, deuterium- and 15N-enriched organic matter is closely associated with presolar silicate grains (Messenger et al. 2005, Nguyen et al. 2007), suggesting an association in the ISM prior to Solar System formation.

We set up a framework for calculating in a precise and controlled way the collisional properties of several molecules of astrophysical meaning. The quantities that are relevant for astrophysics are rotational and vibrational quenching/excitation rates by means of collisions of H2 with water and some organic molecules (HC3N, H2CO). We calculate those rates by means of successively determining a intermolecular potential energy surface and calculating inelastic cross sections and rates classically and/or quantum mechanically. These calculations are part of the European Union FP6 Molecular Universe program.

We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interpla-netary radiation analogs conditions. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using a photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70–80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a stable cation.

A spectral line survey of Orion KL has been performed over the frequency range of 486–492 GHz and 541–577 GHz using the Odin satellite. Over 1000 lines have been identified from 40 different molecular species, including several organic compounds such as methyl cyanide (CH3CN), methanol (CH3OH, 13CH3OH), and dimethyl ether (CH3OCH3).

We report on a search for interstellar CH2D+. Four transitions occur in easily accessible portions of the spectrum; we report on emission at the frequencies of these transitions toward high column density star-forming regions. While the observations can be interpreted as being consistent with a detection of the molecule, further observations will be needed to secure its identification. The CH2D+ rotational spectrum has not been measured to high accuracy. Its lines are weak, as the dipole moment induced by the inclusion of deuterium in the molecule is small. Astronomical detection is favored by observations toward strongly deuterium-fractionated sources. However, enhanced deuteration is expected to be most significant at low temperatures. The sparseness of the available spectrum and the low excitation in regions of high fractionation make secure identification of CH2D+ difficult. Nonetheless, owing to the importance of CH3+ to interstellar chemistry, and the lack of rotational transitions of that molecule owing to its planar symmetric structure, a measure of its abundance would provide key data to astrochemical models.

Aromatic Infrared Bands (AIBs) show significant profile variations in different astrophysical environments. Theoretical IR data is used to develop emission models to understand these variations. A good match with the observed “7.7” μm feature from different regions is obtained.

The present work shows the proportion of interstellar meteors from different mass ranges (exceeding 20 orders of mass scale) detected by various observational techniques. Having analysed the IAU Meteor Data Center, we find that the mass index of interstellar particles continuously increases towards higher masses, but there is a significant change between 10−10 − 10−11 kg. This break is possibly caused by different physical processes leading to different populations of interstellar particles and might be connected with their origin.

We report a spectral line survey of the circumstellar envelopes of evolved stars at millimeter wavelengths. The data allow us to investigate the chemical processes in different physical environments and evolutionary stages. A total of more than 500 emission features (mostly rotational transitions of molecules) are detected in the survey. Our observations show that the sources in different evolutionary stages have remarkably different chemical composition. As a star evolves from AGB stage to proto-planetary nebula, the abundances of Si-bearing molecules (SiO, SiCC, and SiS) decrease, while the abundances of some long-chain molecules, such as CH3CN, C4H, and HC3N, increase. After further evolution to planetary nebula, the abundances of neutral molecules dramatically decrease, and the emission from molecular ions becomes more intense. These differences can be attributed to the changes of the role that dust, stellar winds, shock waves, and UV/X-rays from the central star play in different evolutionary stages. These results will provide significant constraints on models of circumstellar chemistry.

The UV irradiation of interstellar/circumstellar ice analogs is known to lead to the formation of organic compounds such as amino acids and maybe nucleobases. In this work, the mechanisms of formation and distribution of amino acids, chosen as tracers for the organic compounds formed in such experiments, are studied and compared with meteoritic data.

Carbonaceous extraterrestrial matter is observed in a wide variety of astrophysical environments. Spectroscopic signatures reveal a large variety of chemical structure illustrating the rich carbon chemistry that occurs in space. In order to produce laboratory analogues of the carbonaceous cosmic dust, a new chemical reactor has been built in the Laboratoire de Photophysique Moléculaire. It is a low pressure flat burner providing flames of premixed hydrocarbon/oxygen gas mixtures, closely following the model system used by the combustion community. In such a device the flame is a one-dimensional chemical reactor offering a broad range of combustion conditions and sampling which allows production of many and various by-products. In the present work, we have studied the effect of ion irradiation (200-400 keV), at the Laboratorio di Astrofisica Sperimentale in Catania, on several samples, ranging from strongly aromatic to strongly aliphatic materials. Infrared and Raman spectra were monitored to follow the evolution of the films under study, and characterize the irradiation process-induced modifications.