Autoionization and ultrafast relaxation dynamics of highly excited states in N-2

Abstract

We have used the velocity-map imaging (VMI) technique to measure autoionization dynamics in molecular nitrogen initiated by a train of attosecond pulses. The pump-probe measurements show clear evidence of a crossing between potential energy curves of the highly excited N-2(+) ion and of the N-2(2+) ion. It is found that the autoionization becomes energetically allowed when the two nuclei are still very close (similar to 3 A), in contrast with observations in other diatomic molecules, and that it can be coherently manipulated by a strong femtosecond infrared pulse.