[en] Short communication. 6 refs

[en] High-resolution observations at 8579.5 A [Cl II] and 8617 A [Fe II] were carried out with a tilting-filter Fabry-Perot photometer mounted at the Cassegrain focus of the 182 cm (f/9) Asiago telescope in 56 and 43 positions, respectively, across the Orion Nebula (M42) using a 38'' beam

[en] Design and performance of a heatable, easily alignable Pt-nozzle source (pinhole) are described, providing sufficient O₂ intensity in both pure gas and seeded beam operation for crossed beam experiments with metal atoms and mass spectrometric detection. At the chosen skimmer-nozzle distance, nozzle Knudsen numbers around K/subn/approx. =10^-2 gave optimum velocity ratio and intensity for all gas mixtures at nozzle temperatures from 300 to 1300 K. The oven design is particularly suited for effusive metal beams at T<1200 K

[en] Dissociation energy (D₀=4.29+-0.05 eV), threshold energy (E=0.83+-0.05 eV) and forward scattering at a collisional energy Esub(c)=1.1 eV have been found by crossing a thermal beam of Yb atoms with a supersonic seeded beam of He + O₂ at collisional energies up to Esub(c)=1.4 eV. (Auth.)

[en] Comets with large gas production offer a unique chance to observe a H₂-flux of about 10⁵ photon cm^-2s^-1sr^-1 (1 Rayleigh) at wavelengths 8497.4 A, 8560.2 A and 8747.9 A - i.e., where photon counting methods are still applicable. It is shown that population of the vibrational levels, giving rise to these quadrupole overtone transitions, is dominated by photodissociation of methane, and that the emission even of quadrupole lines is not attenuated by collisional quenching. Wavelength scanning by +-1 A is shown to be enough to discriminate between cometary and atmospheric emissions by phase-sensitive subtraction techniques. Solid angle of Ω<10^-7 sr has to be used, whence follows that a large ground-based telescope combined with a tilting Fabry-Perot-filter is best suited for detection of the near-infrared H₂-emissions at reasonable counting rates and sufficient rejection of the atmospheric background. (Auth.)

[en] The search for extraterrestrial and, in particular, interstellar molecules has suddenly increased in the last ten years after the discovery of many complex organic molecules by radioastronomy. Since some very interesting lines are not detectable in the radio region, but only in the middle and far infrared, heterodyne techniques seem to be a powerful tool for interstellar line detection in the submillimetric region and the detection of CO at 870 μ in Orion (Philipps and Huggins, 1977) represents an encouraging success for further efforts in this new field of research. In this work of possibility of observing interstellar lines at heterodyne laser wavelengths already available in laboratory has been considered. Relative intensities for some representative rotational lines of interstellar molecules at three typical temperatures (10, 20, 50 K) have also been computed assuming thermodynamic equilibrium and optically thin regions. The results achieved with hetrodyne laser techniques developed in the laboratory are discussed here in order to study the possibility for ground and space astronomical observations. (Auth.)

[en] In the last years an appreciable experimental effort has been devoted to the ion-atom low energy collisional range investigation. Charge transfer reactions have been studied also with particular interest and applications to astrophysics, ionospheric physics and plasma physics. In spite of the experimental and theoretical efforts, cross section parameters for many charge transfer reactions are still affected by large uncertainty. In the energy range 10-10⁴ eV the experimental technique, which seems to permit the highest accuracy for cross section measurements, is the crossed beam technique, which was here used in the attempt to develope and improve new systems for the investigation of reaction mechanisms occurring in the interstellar medium and in planetary atmospheres. Therefore a novel device was designed for charge transfer reactions in the energy range 20-200 eV and the system was adapted to the molecular beam apparatus of universal type. (Auth.)