THE INTERACTIONS OF RARE-GASES AND ISOTOPIC PAIRS WITH GRAPHITIC CARBON

Thesis/Dissertation · Mon Jan 01 04:00:00 EST 1962

OSTI ID:4723088

Sams, Jr, J R

Data previously obtained in this laboratory for the interactions of gas atoms with surfaces at very low coverages indicated the desirability of using a well-defined, lowsurface-area, homogeneous solid as adsorbent. The highprecision adsorption apparatus, which had been constructed for this purpose, was employed in the present study to obtain data for the interactions of several gases with the highly graphitized carbon black P33 (2700). Neon, argon, krypton, and xenon have been investigated in the secondorder interaction region. The data have been analyzed in terms of a virial-coefficients treatment analogous to that used in imperfect gas theory, to yield gas-surface interaction energies and estimates of the adsorbent surface area. Four different models for the interaction potential and five formulas for obtaining apparent areas from the data have been examined. Third-order interaction data for argon with P33 have been analyzed through a two- dimensional gas treatment. Relations between this treatment and the gassurfuce virial expansion are presented, and the two treatments are shown to be consistent. An independent estimate of the surface area is obtained, and agrees well with values found from second-order data. Data for the argon-P33 system have been obtained for surface coverages up to about 1.5 layers. Heats and entropies of adsorption as a function of coverage obtained from these data are presented and discussed. BET estimates of the area are discussed in light of the independent values mentioned above. The interactions of two isotopic pairs (H/sub 2/-D/sub 2/ and CH/sub 4/-CD/sub 4/) in the second-order region have been studied. In the case of the hydrogen experiments, D/sub 2/ is found to give the anticipated higher interaction energy. The methane results are surprising in that CH/sub 4/ interacts more strongly with the surface than does CD/sub 4/. This inverse effect cannot be explained on the basis of the mass effect on the vibrational levels, and for this reason no quantum mechanical correction has been included in the configuration integral. It is suggested that the second effect which is apparently present may be a rotational one, or may be due to a change in polarizability of the molecules in deuterium substitution. (Dissertation Abstr., XXIII. No. 8)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-17-020050
• OSTI ID: 4723088
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ADSORPTION
ARGON
ATOMS
CARBON
CHEMICAL REACTIONS
CHEMISTRY
DEUTERIUM COMPOUNDS
EXPANSION
HYDROGEN
ISOTOPE EFFECTS
KRYPTON
LABORATORY EQUIPMENT
NEON
QUANTUM MECHANICS
RARE GASES
SOLIDS
SURFACES
THERMODYNAMICS
XENON