ADSORPTION ISOTHERM AND THE STATES OF ADSORPTION

166
J. HORIUTI and T. Toy A
tic ally constant. It requires - 2 e V to make a defect or so-called damage
inside metals2!l, hence about one half of this amount of energy to make an
imperfection on the surface. Since this amount of energy is hardly supplied
thermally over the temperature range in question, we might safely exclude
any possibility of rearrangements of surface metal atoms, hence admit a constant
distribution of sites over the energy of single adatom independent of
temperature.
One of the present authors has deduced 22 ) the distribution function F(E)
from the adsorption isotherm v=v(p) observed at different temperatures
according to the equation
v = r: fJ(E, f/) F(E) dE,
(2. v)
where F(E) dE is the number of sites with the energy of adatom lying between
E and E+dE in terms of the amount of gas fully adsorbed there
and fJ or v the fraction of these sites occupied or the total amount of gas
adsorbed at the hydrogen pressure P. The fJ is expressed in accordance
with the premised absence of interaction among adatoms by the Langmuir
type function
{ ( E-f/)}-I
fJ = l+exp -f