A STUDY OF THE THERMAL ACCOMMODATION OF HELIUM, NEON, ARGON, KRYPTON AND XENON DURING ADSORPTION OF POTASSIUM AND CESIUM ON TUNGSTEN

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

OSTI ID:4755315

Roach, D V

The thermal accommodation coefficient (A. C.) is a measure of the efficiency of energy transfer at a gas-solid interface. The accommodation coefficients of He, Ne, Ar, Kr, and Xe were measured on a W surface as the latter acquired chemisorbed layers of Cs and of K at a steady rate by exposure of the filament to the vapor of these metals at their respective equilibrium pressures. In every case, as the coverage of the tungsten surface increased, the A. C. values increased to a maximum and subsequently decreased, then leveled sharply to a final fixed value, or in some cases went through a shallow minimum to the same final fixed value. These final values of the A. C. were intermediate between the maximum values and the values characteristic of a clean tungsten surface. The contact potential difference change (the negative of the change of the work function) was measured as adsorption of K occurred at one W filament of a vacuum diode at 0.00 deg C. The work function calculated using an average work function of 4.53 volts for W decreased to a minimum of 2.21 volts with a subsequent increase to a fixed final value of 2.58 volts. The times required to acquire coverages to give the minimum work function and the final fixed value were comparable to the times required to reach the maximum and final fixed value of the A. C. The A. C. of helium was used to identify the change of coverage upon establishment of a steady state between Cs vapor at a pressure of about 5 x 10/ sup -10/ mm (-37.32 deg C) and adsorbed Cs at each of several filament temperatures (273 deg K to 800 deg K). (M.P.G.)

• Research Organization: Originating Research Org. not identified
• NSA Number: NSA-17-016027
• OSTI ID: 4755315
• Country of Publication: Country unknown/Code not available
• Language: English

Related Subjects

ADSORPTION
ARGON
CESIUM
CHEMISORPTION
CHEMISTRY
DIFFERENTIAL EQUATIONS
EFFICIENCY
ELECTRIC POTENTIAL
ELECTRODYNAMICS
ENERGY
EQUATIONS
FERMIONS
FIELD THEORY
HELIUM
INTERACTIONS
ISOSPIN
KRYPTON
LAGRANGIAN
LAYERS
MATHEMATICS
MOMENTUM
NEON
NUMERICALS
PARTICLE MODELS
PERTURBATION THEORY
POTASSIUM
PRESSURE
SCATTERING
SEMICONDUCTORS
STABILITY
SURFACES
TEMPERATURE
THERMODYNAMICS
TUNGSTEN
VACUUM
VAPORS
WIRES
XENON