Visualization of Fermi’s Golden Rule Through Imaging of Light Emission from Atomic Silver Chains

Abstract

Silver Emission Follows Golden Rule Electrons emitted from the tip of a scanning tunneling microscope (STM) can be used in certain cases to excite optical emission from surface structure. Such methods can be used to characterize the “particle-in-a-box” states created in chains of varying lengths of metal atoms on surfaces. Chen et al. (p. 981 ) were able to spatially resolve photon emission for silver chains up to 10 atoms long, assembled on a nickel-aluminum alloy surface. The emission maxima correlated with the nodes seen in the derivative of STM current with voltage. This correlation follows from Fermi's golden rule, which connects the initial and final states of the radiation transition through the momentum operator and leads to a better understanding of the light-emission process.