Enormous Yield of Photoelectrons from Small Particles

A new ac bridge technique allows detailed photoelectric studies on very small particles suspended in gases. The photoelectric yield $Y$ near threshold $\Phi$ still follows the Fowler-Nordheim law $Y=c{(h\nu -\Phi )}^2$; yet $c$ is generally much larger compared to surfaces of extended solids. For Ag particles of radius 20 Å in an airlike mixture of ${\mathrm{N}}_2$ and ${\mathrm{O}}_2$, $c\simeq 100c_0$, where $c_0$ applies to a macroscopic Ag surface in the same environment.