Simulations of molecular dynamics carried out for Cu particles with si
zes up to about 17 000 atoms, i.e. up to 70 Angstrom in diameter, have
shown that the surface atoms move in a much more anharmonic potential
than the bulk atoms. Since the fraction of surface atoms increases wi
th decreasing particle size, the pair distribution functions become mo
re and more asymmetric when going to smaller particles. This anharmoni
city may introduce significant errors in the apparent bond distance an
d in the coordination number when determined by use of the standard EX
AFS analysis formalism which assumes that the thermal vibrations are h
armonic. Such errors in the coordination numbers will result in large
errors in the calculated particle sizes. Consequently, a method was de
veloped to correct these errors. In the present work we have extended
the simulation of molecular dynamics to other metals, such as Pt, in a
n attempt to make the above model generally applicable to all transiti
on metals. Since the motion of the atoms in Pt particles is found to b
e more harmonic than the atomic motion in Cu particles, the correction
s for Pt are smaller than for Cu.