Attosecond Time-Resolved Electron Dynamics in the Hydrogen Molecule

Recent advances in the generation and characterization of extreme-ultraviolet pulses, generated either by intense femtosecond lasers or by free electron lasers, are pushing the frontier of time-resolved investigations down to the attosecond domain, the relevant timescale for electron motion. The quantum nature of the intertwined electronic and nuclear motion requires theoretical models going beyond the Born-Oppenheimer approximation and taking into account electron correlation, representing a challenge for the computational power available nowadays. Understanding how the electron dynamics inside molecules can influence chemical reactions presents important implications in several fields and allows for the development of new technologies. In this paper, we report on experimental and theoretical results of an investigation in H₂/D₂, where for the first time control of molecular dynamics with attosecond resolution was achieved. The data represent the first evidence of the control of the electron motion in a molecule undergoing a chemical reaction on the subfemtosecond scale.