Measurement of the positron work functions of iron, molybdenum, titanium, and vanadium

Measurements are reported of the positron work functions of submonolayer contaminated polycrystalline surfaces of copper, iron, molybdenum, titanium, and vanadium. The positron work functions ψ+ were obtained by measuring the spectrum of slow positrons re-emitted by the metal surfaces when bombarded with KeV energy positrons. It is found that ψ+Cu = -0.6 ± 0.2 eV, ψ+Mo = 2.3 ± 0.2 eV, ψ+v = -0.7 ± 0.2 eV, ψ+Fe = -1.2 ± 0.2 eV, and that ψ+Ti is positive