Multiphoton Ionization as a clock to Reveal Molecular Dynamics with Intense Short X-ray Free Electron Laser Pulses

TL;DR

This paper uses multiphoton ionization induced by intense short X-ray free electron laser pulses to study and map molecular dynamics and timing in N2, revealing internuclear separations and ionization timing.

Contribution

It introduces a method to measure molecular ionization timing and dynamics using multiphoton ionization as a clock with X-ray free electron lasers.

Findings

Mapped internuclear separation for each ionization step

Measured average time intervals between photoabsorption events

Demonstrated control of ionization dynamics by varying pulse duration

Abstract

We investigate molecular dynamics of multiple ionization in N2 through multiple core-level photoabsorption and subsequent Auger decay processes induced by intense, short X-ray free electron laser pulses. The timing dynamics of the photoabsorption and dissociation processes is mapped onto the kinetic energy of the fragments. Measurements of the latter allow us to map out the average internuclear separation for every molecular photoionization sequence step and obtain the average time interval between the photoabsorption events. Using multiphoton ionization as a tool of multiple-pulse pump-probe scheme, we demonstrate the modification of the ionization dynamics as we vary the x-ray laser pulse duration.