Pavol Jusko

ION TRAP STUDIES OF H– + H → H2 + e – BETWEEN 10 AND 135 K

Thermal rate coefficients for forming H2 via associative detachment in H– + H collisions were determined using the combination of a 22-pole ion trap (22PT) with a skimmed effusive beam of atomic hydrogen penetrating the ion cloud. The temperature of both reactants have been varied independently (ion trap: T 22PT = 10-150 K, neutral beam accommodator T ACC = 10, 50, 120 K). Using various combinations, the temperature range between 10 and 135 K has been accessed for the first time experimentally. The effective number density of H (typically some 108 cm–3) is determined in situ via chemical probing with CO+ 2 ions. With decreasing temperature, the measured thermal rate coefficients decrease slowly from 5.5 × 10–9 cm3 s–1 at 135 K to 4.1 × 10–9 cm3 s–1 at 10 K. The relative error is 10%, while the absolute values may deviate systematically by up to 40%, due to uncertainties in the calibration reaction. Significant improvements of the versatile and sensitive experiment are possible, e.g., by using electron transfer from H to D+ as calibration standard.

Stabilization of H+–H2 collision complexes between 11 and 28K

Formation of via association of H+ with H2 has been studied at low temperatures using a 22-pole radiofrequency trap. Operating at hydrogen number densities from 1011 to 1014u2009cm−3, the contributions of radiative, kr, and ternary, k3, association have been extracted from the measured apparent binary rate coefficients, k*=kr+k3[H2]. Surprisingly, k3 is constant between 11 and 22u2009K, (2.6±0.8)×10−29u2009cm6u2009s−1, while radiative association decreases from kr(11u2009K)=(1.6±0.3)×10−16u2009cm3u2009s−1 to kr(28u2009K)=(5±2)×10−17u2009cm3u2009s−1. These results are in conflict with simple association models in which formation and stabilization of the complex are treated separately. Tentative explanations are based on the fact that, at low temperatures, only few partial waves contribute to the formation of the collision complex and that ternary association with H2 may be quite inefficient because of the ‘shared proton’ structure of .

Interaction of O− and H2 at low temperatures

Reactive collisions between O(-) and H2 have been studied experimentally at temperatures ranging from 10 K to 300 K using a cryogenic radiofrequency 22-pole ion trap. The rate coefficients for associative detachment, leading to H2O + e(-), increase with decreasing temperature and reach a flat maximum of 1.8 × 10(-9) cm(3) s(-1) at temperatures between 20 K and 80 K. There, the overall reaction probability is in good agreement with a capture model indicating efficient non-adiabatic couplings between the entrance potential energy surfaces. Classical trajectory calculations on newly calculated potential energy surfaces as well as the topology of the conical intersection seam leading to the neutral surface corroborate this. The formation of OH(-) + H via hydrogen transfer, although occurring with a probability of a few percent only (about 5 × 10(-11) cm(3) s(-1) at temperatures 10-300 K), indicates that there are reaction paths, where electron detachment is avoided.

Collisional-radiative recombination Ar{sup +} + e + e: Experimental study at 77-180 K

Rate coefficients for collisional-radiative recombination (CRR) of Ar{sup +} ions with electrons have been measured at temperatures from 77 to 180 K in a helium-buffered flowing-afterglow (Cryo-FALP) experiment at electron densities n{sub e} from 10{sup 8} to 10{sup 10} cm{sup -3}. The measured ternary rate coefficient K{sub CRR} at 77 K is (1.1{+-}0.4)x10{sup -17} cm{sup 6}s{sup -1} and the observed variation with temperature agrees well with the theoretical T{sup -4.5} dependence.

Software-Hardware Mapping in a Robot Design

In this paper we present a way how to change the design of a small robot for Eurobot contest from a design with a lot of hardcoded, hard to maintain and hard to extend functionality to a more universal design with much better maintainability and upgradability by use of software-hardware mapping. In the process, we show how the change of communication topology and software design rework helped to achieve the goal.

Interactions of H? Anions with Atomic Hydrogen?Ion Trap study at 10?100 K

Results of an experimental study of the associative detachment reaction H + H− → H2 + e− and a description of the ion trap apparatus combined with a variable temperature beam of atomic hydrogen are presented.

Robot Localisation in Known Environment Using Monte Carlo Localisation

In this paper we present our approach to localisation of a robot in a known environment. The decision making and the driving is much harder to be done without the knowledge of the exact position. Therefore we discuss the importance of the localisation and describe several known localising algorithms. Then we concentrate on the one we have chosen for our application and outline the implementation supporting various inputs. Combining of the measurements is also discussed. In addition to well known inputs like odometry and other simple inputs we describe deeper our beaconing system which proved to be very useful.