New perspectives in attosecond physics

Recent advances in the generation and characterization of extreme ultraviolet (XUV) pulses are pushing the frontier of time-resolved investigations down to the attosecond domain, the relevant timescale for electronic correlation. In molecules the description of electron-electron interaction and of the correlation among electronic and nuclear degrees of freedom requires theoretical models going beyond the Born-Oppenheimer approximation and represents a challenge for the computational power available nowadays. Understanding how the electron dynamics inside a molecule can influence the outcome of a chemical reaction has attracted increasing efforts in the last years leading to the birth of attochemistry. We report on the first experiment demonstrating an attosecond control of the charge localization in a dissociating molecule of D+2. The experiment was performed by combining a state-of-the-art isolated attosecond source and the velocity map imaging technique. The experimental observations and the theoretical predictions clearly indicate the relevance of the autoionization of the doubly excited states Q1 for the interpretation of the attosecond electron localization. Further information about the autoionization mechanism, such as the lifetime of the Q1 levels, could be inferred by studying the photoelectron angular distribution in the molecular frame by measuring in coincidence the electrons and ions emitted in the photodissociation process.