Revealing and controlling nuclear dynamics following inner-shell photoionization of N2

TL;DR

This study uses advanced simulation techniques to explore and control ultrafast nuclear dynamics in N2 after inner-shell photoionization, revealing how laser parameters influence molecular dissociation processes.

Contribution

It introduces a hybrid energy analysis method and demonstrates time-resolved control of nuclear dynamics in N2 using a femtosecond IR probe.

Findings

Autoionization leads to dissociative and non-dissociative states in N++2.

A hybrid technique effectively extracts the nuclear KER spectrum.

Laser parameters significantly influence nuclear dynamics.

Abstract

In this work, we apply the Monte Carlo wave packet method to study the ultrafast nuclear dynamics following inner-shell photoionization of N2 exposed to an ultrashort intense X-ray pulse. The photon energy of the X-ray pulse is large enough to remove a 1s electron from the N atom in N2. The intermediate state in N+2 is highly excited so that autoionization takes place from this state to the dissociative or non-dissociative electronic states of ungerade and gerade symmetries in N++2. The possible vibrational resonances allowed by the non-dissociative states prevents a direct extraction of the nuclear kinetic release (KER) spectrum from the nuclear wave packets in N++2. Therefore, we propose a hybrid technique by combining the advantages of two energy analysis strategies to obtain the final nuclear KER spectrum of the process. A femtosecond IR probe pulse, which couples the electronic states in N++2 together, is applied to achieve a time-resolved imaging and controlling of the ultrafast dynamics that takes place during double ionization of N2. The influence of the laser parameters including the peak intensity, pulse duration and pump-probe delay, on the nuclear dynamics is also investigated.