Coherence of the electron dynamics during generation of high-order harmonics in molecules

点击翻译按钮获取中文摘要

The generation of high-order harmonics from molecules in strong laser pulses is an important diagnostic tool to gain insight into structure and dynamics of the molecules. High-order harmonic generation takes place as a sequence of ionisation, dynamics of the emerging electron and ion and recombination into the initial state. If the ionisation step prepares a coherent wavepacket in the ion, the wavepacket dynamics can be extracted from the observed spectrum by mapping the photon energies to a range of electron excursion times. If, however, the state of ion and electron is entangled, then the wavepacket dynamics is not fully coherent and possibly not observable. In cooperation of the groups in Hannover and Zürich, the calculation of the degree of coherence from molecular propoerties is to be investigated. The aim is the formulation of a theory that, unlike previous models, describes the general case of partially coherent wavepacket dynamics in high-order harmonic generation. This theory will be connected with existing and planned experiments at the ETH Zürich. In this context, the relaxation of molecular orbitals in the course of ionisation shall be investigated as well.