Hydrogen atom beams

M. Che, M. Richard, and D. OUvier ferromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-exchanged X-zeolites by hydrogen molecules or hydrogen atom beams, J. Chem. Soc. Faraday Trans. 176,1526-1534 (1980). 

Fig. 4. Hydrogen atomic beam apparatus and scheme for laser cooling and magnetic trapping of hydrogen atoms.

Fig. 24 - Experimental set-up for two-photon spectroscopy in a Hydrogen atomic beam.

Borodi G, Luca A, Mogo C, Smith M, Gerhch D. (2007) On the combination of a low energy hydrogen atom beam with a cold multipole ion trap to be submitted to Rev. Sci. Instr. 

Even if such high power levels cannot be sustained, it should still be possible to observe two-photon excitation with the help of more sensitive detection methods. Towards this end, U. Boesl and E. Hildum in our laboratory have recently completed construction of a hydrogen atomic beam apparatus, which permits the detection of 2S atoms via photoionization. The resulting charged particles are observed with a time-of flight mass spectrometer. Despite transit time broadening and uncompensated relativistic second order Doppler shifts, we hope to achieve line widths on the order of 1 Mhz in this... 

Plainly, the agreement between calculation and experiment is too good to be accidental. Our notched beam is a useful basis for interpreting the spectrum of the hydrogen atom. 

Based on the data of hydrogen and oxygen atoms scattering by the surface of ZnO film obtained by the method of atom beams we calculated the degree of ionization of chemosorbed particles on the film using the variation of its conductivity (see Table 3.1) [23]. 

Atoms of metals are more interesting tiian hydrogen atoms, because they can form not only dimers Ag2, but also particles with larger number of atoms. What are the electric properties of these particles on surfaces of solids The answer to this question can be most easily obtained by using a semiconductor sensor which plays simultaneously the role of a sorbent target and is used as a detector of silver adatoms. The initial concentration of silver adatoms must be sufficiently small, so that growth of multiatomic aggregates of silver particles (clusters) could be traced by variation of an electric conductivity in time (after atomic beam was terminated), provided the assumption of small electric activity of clusters on a semiconductor surface [42] compared to that of atomic particles is true. 

For this purpose, the authors used a special vacuum cell with a controlled focused electron beam incident on a zinc oxide film target. In these experiments, the role of the film was twofold. It served as an adsorbent and as a high-sensitivity detector of hydrogen atoms (10 at/cm ). Hydrogein atoms were produced due to surface dissociation of adsorbed molecular hydrogen. This process was induced by heating or bombardment of the adsorbed layer by an electron beam. 

Since our main objective was to remove all the chlorine and hydrogen atoms from the polymer chain, C-PVC films were further exposed to the UV radiation of the medium pressure mercury-lamp. This led to a dark brown material w.hich was found to be unable to carry an electrical current, even after extended irradiation time. Therefore we turned to a powerful laser source, a 15 W argon ion laser tuned to its continuous emission at 488.1 nm. At that wavelength, the degraded polymer film absorbs about 30 % of the incident laser photons. The sample was placed on a X-Y stage and exposed to the laser beam at scanning rates in the range of 1 to 50 cm s, in the presence of air. 

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