Femtosecond photoionization of RbI

Abstract

The photodissociation of RbI at 267 nm was studied by femtosecond pump–probe ionization. The probe process of multiphoton ionization by 800 nm resulted in complicated electron and ion signals for dissociation on a purely repulsive curve. The Rb ion signal, produced by dissociative ionization of RbI, has a fast decay and a delayed rise. Transient zero-kinetic-energy electrons were found in the time-resolved photoelectron spectrum, as well as electrons from normal three-photon ionization. Both electron and ion signals were successfully simulated using a classical trajectory method. It is understood that resonance between excited states and their crossings play important roles during the multiphoton ionization probe process.