THE INTERACTIONS OF NITROGEN AND CARBON MONOXIDE ON POLYCRYSTALLINE TUNGSTEN

1964 ◽  
Vol 42 (6) ◽  
pp. 1256-1269 ◽  
Author(s):  
L. J. Rigby
Keyword(s):  
Carbon Monoxide ◽  
Mass Spectrometer ◽  
Tungsten Wire ◽  
Activation Energies ◽  
Β Phase ◽  
Polycrystalline Tungsten

Desorption spectra from a polycrystalline tungsten wire have been obtained with a mass spectrometer to study: (a) the effect of preadsorbed nitrogen on the adsorption of carbon monoxide; (b) the reversibility and rearrangement of the carbon monoxide monolayer; and (c) the slow replacement of carbon monoxide by nitrogen. Surface coverages have been measured, and the activation energies of desorption obtained for all phases of carbon monoxide and the β phase of nitrogen.

Rates of reaction of Ascaris haemoglobins with ligands

1965 ◽  
Vol 163 (991) ◽  
pp. 206-214 ◽  
Keyword(s):  
Nitric Oxide ◽  
Carbon Monoxide ◽  
Ascaris Lumbricoides ◽  
Kinetic Data ◽  
Body Wall ◽  
Equilibrium Constants ◽  
Activation Energies ◽  
The Body ◽  
Ph Values ◽  
Round Worm

The combination of the body wall and perienteric fluid haemoglobins of the pig round worm, Ascaris lumbricoides , with oxygen, carbon monoxide, and nitric oxide has been followed over a range of temperature and pH values. The rates for the perienteric fluid haemoglobin were NO: 4.7 x 10 6 M -1 S -1 ; O 2 : 1.5 x 10 6 ; CO: 1.7 x 10 5 . The rates for body-wall haemoglobin were 30% less in each case. The rate of dissociation of carbon monoxide is 0.018 S -1 at 20 °C for the perienteric fluid haemoglobin and 0.039 for the body-wall haemoglobin. These rates are similar to those for mammalian haemoglobin. As was already known, the velocity of dissociation of oxygen from these haemoglobins is much lower. The velocity of dissociation for perienteric fluid haemoglobin was difficult to study because of the presence of methaemoglobin. The rates of all the reactions studied were close to those which would be predicted from the activation energies if the reactions were assumed to be kinetically normal. Over-all equilibrium constants for the reactions with oxygen and carbon monoxide have been calculated from the kinetic data. The half-saturation value for the perienteric fluid haemoglobin at 20 °C is 0.0015 mm Hg O 2 . The value for the body-wall haemoglobin is 0.11 mm . The ratio of the oxygen and the carbon monoxide equilibrium constants, M , is 0.075 for perienteric fluid haemoglobin and 0.82 for body-wall haemoglobin. Neither of these values conforms to the relation between log 10 M and the span of haemoglobin observed for mammalian haemoglobins and myoglobin.

Massenspektrometrische Untersuchungen an α,α’-Bis-acetylen-ketonen / Mass Spectrometric Investigations with α,α’-Bis-acetylenic ketones

1971 ◽  
Vol 26 (10) ◽  
pp. 1003-1007 ◽  
Author(s):  
Eugen Müller ◽  
Adolph Segnitz ◽  
Klaus-Peter Zeller
Keyword(s):  
Carbon Monoxide ◽  
Mass Spectrometer ◽  
Ion Source ◽  
Mass Spectrometric

In the ion source of a mass spectrometer α,α’-bis-acetylenic ketones rearrange by elimination of carbon monoxide giving diyne-ion radicals.

Search for 129Xe in Mineral Grains from Allende Inclusions: An Exercise in Miniaturized Rare Gas Analysis

1980 ◽  
Vol 35 (3) ◽  
pp. 257-266
Author(s):  
J. H. Reynolds ◽  
G. R. Lumpkin ◽  
P. M. Jeffery
Keyword(s):  
Mass Spectrometer ◽  
Tungsten Wire ◽  
Gas Analysis ◽  
Ion Source ◽  
Rare Gas ◽  
Minor Phase ◽  
Counting System ◽  
The One ◽  
Almost All

Abstract A static mass spectrometer, modified by installation of a Baur-Signer (Zürich) ion source and an ion-counting system, was used to detect xenon from single mineral grains from inclusions in the C3 meteorite Allende. The grains were melted in small conical heaters wound from tungsten wire. In almost all cases excess 129Xe from 129I decay was detected, in concentrations varying from < 1000 to 600,000 atoms per microgram. Inferred iodine concentrations increased on the average from pentlandite (0.6 ppb), to hedenbergite (21 ppb), to olivine (92 ppb), to enstatite (203 ppb) to melilite (422 ppb), but vary widely from one grain to another of the same mineral, indicating that the iodine resides in some minor phase which is included “spottily” in the bulk phases over which we had good mineralogical control. About 23,000 atoms of fissiogenic 132Xe, presumably from 244Pu decay, was detected in the largest melilite sample analyzed, but we cannot determine from this study whether the 244Pu is “spotty” like 129I or is uniformly distributed in the melilite. One can foresee that if the samples could be loaded into previously outgassed heater cones, a system such as the one described in this paper would have 132Xe blanks of ~ 50,000 atoms. It is likely that in such a system the detectability for excess Xe achieved in this paper (~ 20,000 atoms) could be substantially improved. We also ran St. Severin troilite, which contains less than ~ 33 atoms of excess 129Xe per microgram, and a single chondrule from Alllegan, wich contains higher concentrations of radiogenic xenon than were previously reported by Podosek from runs on a pile-irradiated sample.

THE ADSORPTION AND REPLACEMENT OF HYDROGEN ON POLYCRYSTALLINE TUNGSTEN

1965 ◽  
Vol 43 (6) ◽  
pp. 1020-1035 ◽  
Author(s):  
L. J. Rlgby
Keyword(s):  
Carbon Monoxide ◽  
Second Order ◽  
Tungsten Filament ◽  
Α Phase ◽  
Polycrystalline Tungsten

Desorption spectra have been obtained which show that there are at least three β phases of hydrogen desorbed from a tungsten filament. The β2 phase was desorbed with second-order kinetics. The replacement of hydrogen by nitrogen and by carbon monoxide was observed, and simple replacement mechanisms are proposed for these processes and the replacement of carbon monoxide by nitrogen. When carbon was preadsorbed on the surface, the β1 phase of hydrogen and all the β phases of carbon monoxide and nitrogen were reduced, but the α phase of carbon monoxide was increased. A concept of identical and nonidentical sites is introduced to explain these results.

Photoelectron spectroscopy of the α-Fe(111)-carbon monoxide surface

1977 ◽  
Vol 356 (1684) ◽  
pp. 37-45 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Oxide Layer ◽  
Photoelectron Spectroscopy ◽  
Activation Energies ◽  
Surface Species ◽  
Molecular Binding ◽  
Oxygen Bond ◽  
Monolayer Coverage

Photoelectron spectroscopy of the α-Fe(111)-carbon monoxide surface at 300 K demonstrates a mixed chemisorption régime: dissociation of carbon monoxide and formation of a ‘carbide-oxide’ layer at sub-monolayer coverage is followed by associative molecular binding at higher coverages. No new surface species are detected in mixed carbon monoxide-hydrogen adlayers but preadsorption of dihydrogen considerably reduces the extent of dissociation of subsequently sorbed carbon monoxide. Some general remarks are made on the activation energies for cleavage of the carbon-oxygen bond at various surfaces.

Negative activation energies and curved Arrhenius plots. 2. Hydroxyl + carbon monoxide

1984 ◽  
Vol 88 (25) ◽  
pp. 6435-6441 ◽  
Author(s):  
Michael Mozurkewich ◽  
John J. Lamb ◽  
Sidney W. Benson
Keyword(s):  
Carbon Monoxide ◽  
Activation Energies ◽  
Arrhenius Plots
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