The mobility of adsorbed Na on the (110) face was investigated by measuring the time correlation function of the local field emission current fluctuations for coverages of between 2 x 1013 and 3 x 1014/cm2, at 170 to 500K. Two ranges of temperature behavior were detected, within which the diffusion parameters were completely different:

2.00 x 1013/cm2, >267K:     D (cm2/s) = 2.5 x 10-8 exp[-0.27(eV)/kT]

1.25 x 1014/cm2, >260K:     D (cm2/s) = 4.0 x 10-6 exp[-0.35(eV)/kT]

2.30 x 1014/cm2, >305K:     D (cm2/s) = 6.3 x 10-3 exp[-0.58(eV)/kT]

3.00 x 1014/cm2, >275K:     D (cm2/s) = 1.4 x 10-4 exp[-0.44(eV)/kT]

2.00 x 1013/cm2, <267K:     D (cm2/s) = 1.3 x 10-12 exp[-0.055(eV)/kT]

1.25 x 1014/cm2, <260K:     D (cm2/s) = 3.2 x 10-12 exp[-0.053(eV)/kT]

R.Morin: Journal de Physique - Colloque C9, 1984, 45[12], 17-21