Reactions of Hot Hydrogen Atoms in Gaseous Hydrogen Chloride and Hydrogen Bromide

1973 ◽  
Vol 51 (5) ◽  
pp. 656-666 ◽  
Author(s):  
D. K. Jardine ◽  
N. M. Ballash ◽  
D. A. Armstrong
Keyword(s):  
Carbon Dioxide ◽  
Cross Section ◽  
Hydrogen Bromide ◽  
Gaseous Hydrogen ◽  
Initial Kinetic Energy ◽  
Zero Energy ◽  
Hydrogen Atoms ◽  
Abstraction Reaction ◽  
Thermal Region ◽  
The Cross

Hydrogen atoms of initial kinetic energy E0 = 1.15 or 2.1 eV were produced photolytically and their reactions with HCl were studied at 300 °K using bromine as a scavenger. The fraction, FH, undergoing reaction 2 while hot was found to be 0.79 ± 0.02 and 0.55 ± 0.02 for E0 = 2.1 and 1.15 eV, respectively.[Formula: see text]For 2.1 eV atoms a similar result was obtained at 200 °K with chlorine as scavenger. On the addition of carbon dioxide as a moderator FH decreased in a manner consistent with the kinetic theory of hot atom reactions. Comparison of the present results with previous work on the D + DCl abstraction reaction showed that the cross section of the latter is probably 20 to 50% higher than that of H + HCl. The cross section of reaction 2 appears to increase with energy over most of the 0.1 to 1.1 eV range and possibly also above it. Its average magnitude over this energy region was estimated to be [Formula: see text].For atoms of E0 = 1.15 eV reacting in HBr FH is close to unity. The threshold of reaction 3′[Formula: see text]is near zero energy and its cross section rises rapidly, becoming [Formula: see text] in the thermal region for 300 °K.

Hg(63P1)-sensitized decomposition of HNCO vapor and HNCO–H2 mixtures; the reaction of hydrogen atoms with HNCO

1968 ◽  
Vol 46 (4) ◽  
pp. 527-530 ◽  
Author(s):  
N. J. Friswell ◽  
R. A. Back
Keyword(s):  
Quantum Yield ◽  
Cross Section ◽  
Initial Step ◽  
Primary Process ◽  
Hydrogen Atoms ◽  
Direct Photolysis ◽  
A Value ◽  
The Cross

The Hg(63P1)-sensitized decomposition of HNCO vapor has been briefly studied at 26 °C with HNCO pressures from about 3 to 30 Torr. The products detected were the same as in the direct photolysis, CO, N2, and H2. The quantum yield of CO was appreciably less than unity, compared with a value of 1.5 in the direct photolysis under similar conditions. From this and other observations it is tentatively concluded that a single primary process occurs:[Formula: see text]From a study of the mercury-photosensitized reactions in mixtures of HNCO with H2, it was concluded that hydrogen atoms react with HNCO to form CO but not N2. The initial step is probably addition to form NH2CO. From the competition between reaction [1] and the corresponding quenching by H2, the cross section for reaction [1] was estimated to be 2.3 times that of hydrogen.

The application of variational methods to atomic scattering problems V. The zero energy limit of the cross-section for elastic scattering of electrons by hydrogen atoms

1957 ◽  
Vol 241 (1227) ◽  
pp. 522-530 ◽  
Keyword(s):  
Elastic Scattering ◽  
Variational Methods ◽  
Cross Section ◽  
Trial Function ◽  
Central Field ◽  
Zero Energy ◽  
Hydrogen Atoms ◽  
Scattering Problems ◽  
Atomic Scattering ◽  
Exchange Polarization

Calculations have been made using the central-field, exchange and exchange-polarization approximations. In agreement with previous work it is found that the wave functions are profoundly modified by inclusion of exchange. The exchange radial equations are solved by numerical integration and by variational methods; consideration of the form of the equations for moderately large radial distances suggests an improved two-parameter trial function which is found to give satisfactory results. Polarization, i. e. the inclusion of the interelectronic distance r 12 in the trial function, is much more important for the symmetric than for the anti-symmetric case. A symmetric exchange-polarization trial function is obtained which appears more satisfactory than those previously employed. It may be hoped that the final result for the zero-energy elastic scattering cross-section, Q (0) = 5·76 x 10 -15 cm 2 , is correct to within about 15%.

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

The determination of cross sections for quenching of resonance radiation of metal atoms III. Results for thallium

1968 ◽  
Vol 303 (1475) ◽  
pp. 467-475 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Cross Section ◽  
Cross Sections ◽  
Rate Constants ◽  
Resonance Radiation ◽  
Metal Atoms ◽  
The Cross

The intensity of fluorescence of thallium has been measured in hydrogen-oxygen flames diluted with each of the gases, argon, helium, nitrogen and carbon dioxide and the measurements used to obtain the following values for the quenching cross section (Å 2 ) for the 7 s 2 S ½ state of thallium σ 2 H 2 = 0.03, σ 2 O 2 = 13.2 ± 1.5, σ 2 N 2 = 6.4 ± 0.2, σ 2 H 2 O = 1.75 ± 0.2, σ 2 CO = 13.6 ± 0.8, σ 2 CO 2 = 32.5 ± 1.5, σ 2 Ar ≤ 0.1, σ 2 He ≤ 0.12. These values for the cross sections have been used to re-calculate the rate constants of the reactions, Tl + H + X → H X + Tl*, where X = H, OH, Cl or Br, from the data obtained by Phillips & Sugden (1961). The re-calculated values are lower than the original ones by a factor of 2.2.

Monte-Carlo simulation of hydrogen-atom recombination

1973 ◽  
Vol 333 (1595) ◽  
pp. 419-434 ◽  
Keyword(s):  
Hydrogen Atom ◽  
Cross Section ◽  
Rate Constant ◽  
Relative Velocity ◽  
Classical Trajectory ◽  
Hydrogen Atoms ◽  
Order Of Magnitude ◽  
The Cross ◽  
The Right ◽  
Right Order

Classical trajectory calculations have been used to calculate the cross-section (and hence the rate constant) for the recombination of hydrogen atoms on a third hydrogen atom, in the temperature range 500–6000 K. The model involves the stabilization of a quasi-bound molecule in an encounter with the third atom. The results indicate that the cross-section for direct stabilization is small and insensitive to the relative velocity, whereas the cross-section for exchange stabilization is large at low velocities and decreases rapidly as the relative velocity is increased. The calculated rate constant, although of the right order of magnitude at 500 K, does not exhibit the anomalous features previously observed experimentally at higher temperatures.

scholarly journals Local Deplanation Of Double Reinforced Beam Cross Section Under Bending

2015 ◽  
Vol 45 (4) ◽  
pp. 31-40 ◽  
Author(s):  
Anguel Baltov ◽  
Ana Yanakieva
Keyword(s):  
Cross Section ◽  
Recycled Concrete ◽  
Thin Layers ◽  
Zero Energy ◽  
Transitional Area ◽  
Composite Layers ◽  
External Moment ◽  
The Cross ◽  
Bending Of Beams ◽  
Reinforcing Layer

Abstract Bending of beams, double reinforced by means of thin composite layers, is considered in the study. Approximate numerical solution is proposed, considering transitional boundary areas, where smooth quadratic transition of the elasticity modulus and deformations take place. Deplanation of the cross section is also accounted for in the areas. Their thickness is found equalizing the total stiffness of the cross section and the layer stiffness. Deplanation of the cross section of the transitional area is determined via the longitudinal deformation in the reinforcing layer, accounting for the equilibrium between the internal and the external moment, generated by the longitudinal stresses in the cross section. A numerical example is given as an illustration demonstrating model’s plausibility. The model allows the design and the calculation of recycled concrete beams double reinforced by means of thin layers. The approach is in agreement with modern design of nearly zero energy buildings (NZEB).

Spin-change cross-sections

1961 ◽  
Vol 262 (1308) ◽  
pp. 132-135 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Change Process ◽  
Change Processes ◽  
Hydrogen Atoms ◽  
Atomic Systems ◽  
The Cross

A quantal formulation of spin-change processes in collisions of atomic systems is presented. The cross-section for the spin-change process in the collision of two hydrogen atoms is computed for temperatures up to 10000°K and the results given in a table.

The attachment of slow electrons in carbon dioxide

1960 ◽  
Vol 254 (1277) ◽  
pp. 229-241 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Kinetic Energy ◽  
Cross Section ◽  
Electron Affinity ◽  
Negative Ions ◽  
Negative Ion ◽  
Initial Kinetic Energy ◽  
A Value ◽  
Normal Electron ◽  
Peak Cross Section

The formation of positive and negative ions in carbon dioxide has been investigated by means of a Lozier apparatus. The negative ion process was interpreted as CO 2 + e → CO( X 1 Σ + ) + O - (2 P 0 ). The (peak) cross-section for electron attachm ent was found to be 5·07 ± 0·5 x 10 -19 cm 2 at 7·8 eV, and the ionization cross-section reached a m axim um value of 6·80 x 10 -16 cm 2 at 85 eV. Measurements of the electron affinity of oxygen by the normal electron impact method yielded a value of 1·6 ± 0·2 eV for O - ions formed with an initial kinetic energy of 1·8 eV. It is shown that this apparent value of electron affinity must be corrected, because of the initial kinetic energy of the ions and the energy spread of the source electrons, and then yields a value of 1·2 ± 0·3 eV.

scholarly journals Charge Exchange Collisions Involving Multielectron Atoms (Lithium and Sodium)

1968 ◽  
Vol 21 (6) ◽  
pp. 793 ◽  
Author(s):  
JG Lodge ◽  
RM May
Keyword(s):  
Excited State ◽  
Cross Section ◽  
Charge Exchange ◽  
Correction Factor ◽  
Ground State ◽  
Hydrogen Atoms ◽  
Sodium Atoms ◽  
The Cross ◽  
Multielectron Atoms

The cross section for forming both ground state and excited state hydrogen atoms by charge exchange between protons and lithium or sodium atoms is calculated. These calculations are performed using the Brinkman-Kramers approximation along with a multiplicative correction factor; the target lithium and sodium atoms are first described by simple "effective-Z" wavefunctions, and then the lithium case is treated more accurately both by including the inner electrons and by using a more accurate numerical lithium wavefunction.

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