554
NOTES
For a heatJingrate dT/dt, I becomes I
=
olWOlc'exp( -
li
Wt 1
IC' dT)
(3)
Solviiig and expanding ( 3 ) with the heating rate one gets
Vol. 66
TRANSLATIONAL ENERGY ACCOMMODATION I N THE S I C K E L C H L O R I N E SURFACE REACTION1 BYJ. D. MCKINLEY Natzonal Bureau of Standards, Washington, D. C. Receaved September 11, 1961
A method of measuring the transfer of translational energy in gas-surface collisions is described. The experiments are part of an experimental inIf the number of trapped electrons undergoing vestigation of the kinetics of the high temperature radiationless recombination is negligible, No and surface reaction between chlorine and nickel.2 Mass N can be expressed in t e r m of the int#egralsof the spectrometric measurements were made of a colliemission intensities and the number of radiating mated beam of unreacted chlorine reflected from electrons so that the specific rate coiistant, from the nickel surface at surface temperatures between (4), becomes 1100 and 16OOOK. By a simple modification of the mass spectrometer ion source it was possible to measure the flux and density of this beam. The latter equals the flux divided by the average velocity of the beam molecules, and the ratio of the two Equations 1 to 5 may be used to analyze the quantities gives the average beam velocity. The data as illustrated below, using the experimental accommodation coefficient of the beam gas on the curve a t 100°I
