Adsorption of H/sub 2/ and D/sub 2/ on Fe(110). 1. Helium scattering as a probe of adsorption. Interim report

Technical Report · Thu Jul 30 04:00:00 EDT 1987

OSTI ID:5974402

Kurz, E A; Hudson, J B

Results of thermal-energy atom scattering (TEAS) measurements of hydrogen and deuterium adsorption-desorption kinetics on iron (110) are presented in detail, with emphasis on the strength and pitfalls inherent in this recently developed technique. It is shown that, for this system, adlayer coverage is directly related to the height of the specularly scattered peak from an incident helium atomic or deuterium molecular beam. The scattered peak height was used to monitor surface concentration as adsorption or desorption occurred, and at equilibrium. Measurements were carried out both at constant temperatures and during temperature programmed desorption. The cross sections for helium scattering from deuterium and hydrogen on Iron (110) were found to be 3.4 A squared and 3.5 A squared, respectively. The cross section for D/sub 2/ scattering from adsorbed deuterium on Fe(110) was measured as 11.0 A squared. The initial sticking coefficient and the rate of adsorption were found to be independent of temperature for both H/sub 2/ and D/sub 2/. The desorption kinetics were found to be second order, with activation energies of 26.5 kcal/mole (D/sub 2/) and 25.0 kcal/mole (H/sub 2/). The isosteric heats of adsorption are 24.7 kcal/mole (D/sub 2/) and 24.2 kcal/mole (H/sub 2/).

• Research Organization: Rensselaer Polytechnic Inst., Troy, NY (USA). Dept. of Materials Engineering
• OSTI ID: 5974402
• Report Number(s): AD-A-183354/0/XAB; TR-2
• Country of Publication: United States
• Language: English

Related Subjects

656003* -- Condensed Matter Physics-- Interactions between Beams & Condensed Matter-- (1987-)
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ACTIVATION ENERGY
ADSORPTION
ATOMS
CROSS SECTIONS
DESORPTION
DEUTERIUM
DIMENSIONS
ELECTROMAGNETIC RADIATION
ELEMENTS
ENERGY
FLUIDS
GASES
HEIGHT
HELIUM
HYDROGEN
HYDROGEN ISOTOPES
IRON
ISOTOPES
KINETICS
LIGHT NUCLEI
METALS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
PROBES
RADIATIONS
RARE GASES
SCATTERING
SORPTION
SORPTIVE PROPERTIES
STABLE ISOTOPES
SURFACE PROPERTIES
SURFACES
THERMAL RADIATION
TRANSITION ELEMENTS