Photofield emission from transition-metal surface states

Studies of photofield emission from surface states on W(100), Mo(100), and Ir(111) are reported. The yield of photofield electrons from the W(100) surface states are analyzed for photon energies between 2.41 and 3.54 eV. The polarization dependence of the photofield current from W(100) and Ir(111) surface states is measured and found to depend on the normal component of the vector potential A. Little evidence for the nonlocal coupling of the different components of A at a transition-metal surface is found.