Correlated electronic and nuclear motion in molecules

• Applicant: Dr. Claus-Peter Schulz
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2013 to 2019
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 233471155

In this project we will investigate time-resolved electronic and nuclear dynamics in molecules. In particular, we want to study the coupling of electronic degrees of freedom and the coupling of electronic and nuclear degrees of freedom, in small diatomic to mid-size polyatomic molecules, and on timescales ranging from attoseconds to a few femtoseconds. In the initial phase of the project strong field ionization (SFI) will be utilized to probe the induced adiabatic and non-adiabatic multi-electron dynamics. To this end, we aim to measure the fragment ion and electron momentum in coincidence and with full angular resolution, thereby allowing us to study the breakdown of the single active electron (SAE) approximation in the molecular frame. In a later stage of the project two-colour XUV+IR pump-probe spectroscopy will be used to study purely electronic dynamics and coupled electronic and nuclear dynamics induced in molecules. Two different scenarios will be investigated. After SFI the breakdown of the SAE approximation leads to the production of a coherent superposition of electronic states in the molecular ion, and hence to electronic dynamics on the attosecond to few-femtosecond timescale, which may couple to nuclear dynamics as well. In this scenario we will use attosecond pulses to probe this coupled electronic and nuclear dynamics. In the second scenario we will study purely electronic dynamics and coupled electronic and nuclear dynamics induced in molecules by an ionizing attosecond pulse. The ensuing dynamics will be probed by the field of an IR pulse, which coherently couples different excited ionic states.These experiments will be enabled by bringing together three forefront technologies: (i) a high repetition rate (400 kHz) few-cycle laser based on Optical Parametric Chirped Pulse Amplification (OPCPA) technology, (ii) attosecond pulse generation by high harmonic generation in a tight-focussing geometry, and (iii) the use of a reaction microscope that allows simultaneous and coincident determination of the full 3D momentum vectors of several charged reaction fragments (electrons, ions), and thereby to follow in real time the evolution of the electronic and nuclear structure of the molecules.

• DFG Programme: Research Grants
• Participating Person: Professor Dr. Marc Vrakking