Experimental observation of excess-photon detachment of negative ions

Abstract

Negative chlorine ions are stored in a Penning trap and are exposed to short (35 ps) and intense (up to 3×${10}^{12}$ W/${\mathrm{cm}}^2$) optical pulses with a wavelength of 1064 nm. The detached electrons are detected in energy-resolved measurements. Absorption is observed of up to two photons in excess of what is required on the basis of the electron affinity.