13/12-2017 Ruaridh Forbes

Strong laser-field based methods such as high-harmonic generation and strong-field ionization (SFI) are considered novel probes of ultrafast molecular dynamics. Details of an experimental femtosecond time-resolved SFI study of the excited state dynamics of NO$_{2}$ using channel-resolved above-threshold ionization (CRATI) as the probe technique will be presented. CRATI makes use of PhotoElectron-PhotoIon COincidence (PEPICO) spectroscopy to study correlations in fragmentation dynamics in molecular systems. The use of PEPICO and covariance methods allows us to correlate ATI photoelectrons associated with a particular SFI electron orbital ionization channel. In disentangling the excited state dynamics of NO$_{2}$, the complex roles of one-photon excitation, multiphoton excitation to higher-lying neutral states, non-adiabatic dynamics and several neutral and ionic dissociation channels are examined. The results will likely have implications for all SFI based time-resolved studies in polyatomic molecules.