Momentum-resolved above-threshold ionization of deuterated water

Abstract

We present momentum-resolved coincidence measurements of strong-field single and double ionization of deuterated water $({\mathrm{D}}_{2}\mathrm{O})$ using intense few-cycle laser pulses. We measure the vector momentum of electrons and ions resulting from the laser-molecule interaction. This enables us to measure the photoelectron spectrum for electrons in coincidence with fragment ions having different momenta, which can be related to different final states of the cation and dication. The photoelectron spectra for different fragment ion momenta show striking differences, which can be interpreted in terms of the removal of electrons from different molecular orbitals, including the highest occupied molecular orbital (HOMO), as well as more deeply bound ones (e.g., HOMO-2). We discuss our measurements in light of calculations which model the strong-field light matter interaction.