The dissociation of hydrogen by tungsten

1936 ◽  
Vol 32 (4) ◽  
pp. 648-652 ◽  
Author(s):  
G. Bryce
Keyword(s):  
Tungsten Oxide ◽  
Constant Temperature ◽  
Atomic Hydrogen ◽  
Square Root ◽  
Tungsten Filament ◽  
Hydrogen Atoms ◽  
Production Of Hydrogen

The dissociation of hydrogen by a hot tungsten filament has been studied under conditions such that all the atomic hydrogen produced is effectively removed by reaction with molybdenum or tungsten oxide. The rate of production of atomic hydrogen is many times greater than was inferred from earlier work. With the tungsten at constant temperature the rate of dissociation is proportional to the square root of the pressure. A formula is given for the rate of production of hydrogen atoms per sq. cm. of the tungsten per second.

The State of Hydrogen Desorbing from Intermediates Formed by Ammonia Interaction with Tungsten Surfaces

1974 ◽  
Vol 52 (7) ◽  
pp. 1147-1154 ◽  
Author(s):  
Y. K. Peng ◽  
P. T. Dawson
Keyword(s):  
Hydrogen Atom ◽  
Atomic Hydrogen ◽  
Surface Concentration ◽  
Hydrogen Desorption ◽  
Pure Hydrogen ◽  
Adsorbed Hydrogen ◽  
Tungsten Filament ◽  
Hydrogen Atoms ◽  
Ionization Source ◽  
Hydrogen Desorbing

Ammonia interaction with a tungsten surface can generate dense adlayers containing nitrogen and hydrogen, i.e. an η-species of surface stoichiometry Ws2N3H. In thermal desorption mass spectrometry experiments, hydrogen desorbing from the η-species interacts with the glass wall in a manner similar to that previously observed for atomic hydrogen. This paper describes two mass spectrometric techniques designed to confirm this conclusion directly. The first method uses a line-of-sight geometry between the tungsten filament and the ionization source of the mass spectrometer and the results indicate that, at least, part of the hydrogen desorbing from the η-species does so atomically. In the second method a multiple wall collision geometry is used but prior saturation of the wall with D atoms will result in an HD+ ion current for desorbing H atoms. The results suggest that 26% of the hydrogen desorbs atomically. Hydrogen atom desorption from the η-species occurs at tungsten filament temperatures below those required for hydrogen atom evaporation from a pure hydrogen adlayer. It is proposed that a reduced binding energy for adsorbed hydrogen atoms and a reduced mobility of these adatoms arises from the presence of a large surface concentration of nitrogen. This will result in the rates of atomic hydrogen desorption and bimolecular recombination becoming comparable at temperatures lower than is the case for pure hydrogen interaction with tungsten. The implications of these results for the ammonia synthesis reaction are discussed.

scholarly journals Сечения образования ионов He-=SUP=-+-=/SUP=- в различных электронных состояниях при столкновениях ионов He-=SUP=-2+-=/SUP=- с атомами водорода

2020 ◽  
Vol 90 (6) ◽  
pp. 895
Author(s):  
А.А. Басалаев ◽  
В.В. Кузьмичев ◽  
М.Н. Панов ◽  
О.В. Смирнов
Keyword(s):  
Kinetic Energy ◽  
Electron Capture ◽  
Cross Sections ◽  
Atomic Hydrogen ◽  
Precision Measurements ◽  
Capture Cross ◽  
Hydrogen Atoms ◽  
Hydrogen Target ◽  
Degree Of Dissociation ◽  
Capture Cross Sections

Using collision spectroscopy based on precision measurements of the kinetic energy of projectile ions that capture an electron, we measured the state selective electron capture cross sections of formation of He^+(n) ions at collision 3^He^{2 +} ions with an energy of E = 1.4-10 keV/a.m.u. with hydrogen atoms. The atomic hydrogen target with a degree of dissociation 78% at a temperature of tungsten dissociation cell 2180K has been made.

Photodissociation of H2 near Threshold Energies

1970 ◽  
Vol 25 (2) ◽  
pp. 237-242 ◽  
Author(s):  
F. J. Comes ◽  
U. Wenning
Keyword(s):  
Electric Field ◽  
Cross Section ◽  
Configuration Interaction ◽  
Atomic Hydrogen ◽  
Molecular Hydrogen ◽  
Hydrogen Atoms ◽  
Dissociation Cross Section ◽  
Excited Molecules ◽  
Threshold Energies ◽  
Near Threshold

Abstract Measurements of the atomic hydrogen fluorescence (Lyα) yield important information on the dissociation behavior of molecular hydrogen under photon impact. Under certain assumptions the dissociation cross section of the molecule can be deduced from such experiments. By applying an appropriate electric field in the observation region those dissociations leading to the formation of metastable hydrogen atoms can be quantitatively determined. This information opens the possibility to describe the predissociation of the excited H2-molecules in the C-, D-and B″-states. The experiments show that the excited molecules in these particular states dissociate into H(1S) and H(2S) by configuration interaction with the B′-state.

THE REACTION OF DEUTERIUM ATOMS WITH ETHYLENE

1956 ◽  
Vol 34 (8) ◽  
pp. 1061-1073 ◽  
Author(s):  
S. Toby ◽  
H. I. Schiff
Keyword(s):  
Isotopic Composition ◽  
Isothermal Calorimetry ◽  
Reaction Rates ◽  
Recombination Coefficient ◽  
Tungsten Filament ◽  
Hydrogen Atoms ◽  
Atom Concentration ◽  
Metaphosphoric Acid ◽  
Detector Position ◽  
Reactant Flow

Deuterium was dissociated on a hot tungsten filament and the atom concentration measured by isothermal calorimetry. The recombination coefficient of deuterium atoms on a glass surface, coated with metaphosphoric acid, was found to be 3.8 × 10−5, and similar to that found for hydrogen atoms. The reactions of H-atoms and D-atoms with ethylene were found to be very rapid. The effects on the yields of the products and on their isotopic composition of variations of reactant flow rate, atom concentration, pressure, and atom-detector position were studied. The major products were methanes, ethanes, and ethylenes, with minor amounts of propanes and butanes. The methanes were always highly deuterated while the ethanes were slightly deuterated. A mechanism is proposed to explain the observations based on a flow pattern in the reaction zone. The possibility of differences in the reaction rates of variously deuterated intermediates is also discussed.

Stationary inverted Lyman populations and free-free and bound-free emission of lower-energy state hydride ion formed by an exothermic catalytic reaction of atomic hydrogen and certain group I catalysts

Open Physics ◽  
2010 ◽  
Vol 8 (1) ◽  
Author(s):  
Randell Mills ◽  
William Good ◽  
Peter Jansson ◽  
Jiliang He
Keyword(s):  
Catalytic Reaction ◽  
Atomic Hydrogen ◽  
Microwave Plasma ◽  
Energy State ◽  
Resonance Energy Transfer ◽  
Resonance Energy ◽  
Hydrogen Atoms ◽  
Hydride Ion ◽  
Group I ◽  
Excess Power

AbstractRb+ to Rb2+ and 2K+ to K + K2+ each provide a reaction with a net enthalpy equal to the potential energy of atomic hydrogen. The presence of these gaseous ions with thermally dissociated hydrogen formed a plasma having strong VUV emission with a stationary inverted Lyman population. Significant Balmer α line broadening of 18 and 9 eV was observed from a rt-plasma of hydrogen with KNO3, and RbNO3, respectively, compared to 3 eV from a hydrogen microwave plasma. The reaction was exothermic since excess power of about 20 mW/cc was measured by Calvet calorimetry. We propose an energetic catalytic reaction involving a resonance energy transfer between hydrogen atoms and Rb+ or 2K+ to form a very stable novel hydride ion. Its predicted binding energy of 3.0471 eV with the fine structure was observed at 4071 Å, and its predicted bound-free hyperfine structure lines matched those observed for about 40 lines to within.01 percent. Characteristic emission from each catalyst was observed. This catalytic reaction may pump a CW HI laser.

Curve-crossing collisions of excited lead atoms in flames

1981 ◽  
Vol 376 (1767) ◽  
pp. 545-564 ◽  
Keyword(s):  
Rate Constant ◽  
Atomic Hydrogen ◽  
Negative Temperature Coefficient ◽  
Negative Temperature ◽  
Model Systems ◽  
Attractive Potential ◽  
Hydrogen Atoms ◽  
Lennard Jones ◽  
Increasing Temperature ◽  
Curve Crossing

Lead atoms, present as a trace additive in a series of premixed H 2 –N 2 –O 2 flames, were excited to the 7 3 P o 1 state by 405.8 nm radiation from a nitrogen-pumped dye laser. Rate constants for spin-orbit relaxation to the 7 3 P o 0 state were obtained separately for collisions with atomic hydrogen and for collisions with the bulk flame gas, by measuring the relative intensities of fluorescence at 364.0 and 368.3 nm as a function of distance from the reaction zone in each flame. For hydrogen atoms the rate constant is typically 1 x 10 -9 cm 3 molecule -1 s -1 , decreasing with increasing temperature; for the bulk flame gas the rate constant is typically 1 x 10 -11 cm 3 molecule -1 s -1 , increasing with increasing temperature. Numerical calculations for model systems, with the use of Morse and Lennard-Jones potentials to describe the interaction of the colliding species, show that the negative temperature coefficient found for atomic hydrogen can be attributed to the crossing of attractive potential curves, corresponding to bound excited states of PbH.

Measurements of the cross section for the production of hydrogen atoms in the metastable excited 2S state

1962 ◽  
Vol 3 (2) ◽  
pp. 62-63 ◽  
Author(s):  
L. Colli ◽  
F. Cristofori ◽  
G.E. Frigerio ◽  
P.G. Sona
Keyword(s):  
Cross Section ◽  
Hydrogen Atoms ◽  
Production Of Hydrogen ◽  
The Cross

scholarly journals Design of Transversal Phase Space Meter for Atomic Hydrogen Beam Source

2016 ◽  
Vol 40 ◽  
pp. 1660101
Author(s):  
A. S. Belov
Keyword(s):  
Phase Space ◽  
Atomic Beam ◽  
Atomic Hydrogen ◽  
Ion Beam ◽  
Longitudinal Velocity ◽  
Sensitive Detector ◽  
Hydrogen Atoms ◽  
Beam Source ◽  
Hydrogen Beam ◽  
Beam Technique

For optimization of polarized atomic beam sources apparatus it is important to have detailed information about characteristics of sources of hydrogen atoms, especially, taking into account present intensity limitations of polarized atomic beam sources. Usually, longitudinal velocity distribution of hydrogen atoms produced by RF dissociator is measured while transversal phase space of unpolarized atomic hydrogen beams was not measured up to now. In this work we report and discuss a design of transversal phase space meter for pulsed atomic hydrogen beam source. The meter design is based on “two slits” method which is well known from ion beam technique. Specific feature of the meter are movable sensitive detector of hydrogen atoms and molecules.

The mechanism of the production of atomic hydrogen by hot tungsten

1936 ◽  
Vol 32 (4) ◽  
pp. 653-656 ◽  
Author(s):  
J. K. Roberts ◽  
G. Bryce
Keyword(s):  
Temperature Variation ◽  
Atomic Hydrogen ◽  
Hydrogen Molecule ◽  
Hydrogen Pressure ◽  
The Other ◽  
Square Root ◽  
Important Process ◽  
Experimental Conditions ◽  
Tungsten Atom ◽  
Tungsten Surface

The fact that the rate of production of atomic hydrogen at a tungsten surface at a given temperature is proportional to the square root of the hydrogen pressure means either that the important process is the evaporation of atoms from an adsorbed film which over the whole range of experimental conditions is sparsely occupied, or that the production of atoms is in the main due to a process in which a hydrogen molecule strikes a bare tungsten atom in the surface, one atom being adsorbed and the other evaporating and the surface being almost completely covered over the whole range of experimental conditions. Either process leads to a temperature variation in the rate of atom production in agreement with experiment. A definite decision between the two processes cannot yet be made.

Reaction of atomic hydrogen with tetrafluoroethene

1969 ◽  
Vol 47 (10) ◽  
pp. 1696-1698
Author(s):  
Lei Teng ◽  
W. E. Jones
Keyword(s):  
Electric Discharge ◽  
Discharge Tube ◽  
Atomic Hydrogen ◽  
Hydrogen Atoms

Hydrogen atoms, generated in a Wood's electric discharge tube, were allowed to react with tetrafluoroethene. The products of the reaction were found to be HF, C2F3H, C2H2, C2F2H2, C2F4H2, C2FH3, C2H4, and CHF3. The formation of the products with the exception of HF was studied quantitatively from 30–330 °C.

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