Periodic Reporting for period 3 - eDrop (Droplet Photoelectron Imaging)
Okres sprawozdawczy: 2022-11-01 do 2024-04-30
Building on our proof-of-principle studies, we propose to exploit the versatility of the droplet approach to address fundamental questions regarding electron dynamics in liquids and across interfaces: Can this new tool provide the missing data for low-energy electron scattering in water and other liquids and resolve the issue of the “universal curve”? How do slow electrons scatter across liquid-gas and buried liquid-liquid/solid interfaces and how does this depend on the composition and curvature of the interface? How is the ultrafast relaxation dynamics of electrons following above-band-gap excitation influenced by electron scattering and confinement effects? Low-energy electron scattering is a determining factor in radiation chemistry and biology and a central aspect of the solvated electron dynamics, while interfacial processes play a key role in atmospheric aerosols. Droplet photoelectron imaging opens up new ways to study such phenomena.
Exploiting such finite-size effects enabled us to retrieve accurate information about how slow electrons lose energy and change their direction when they travel through liquid water; i. e. information about electron scattering in liquid water. Detailed knowledge of electron scattering in water is, for example, crucial for a better understanding of energy dissipation processes that are relevant to radiation chemistry and biology.
The hydrated electron is a species that is supposed to play an important role in the chain of radiation damage processes in biological material. Hence, knowledge of its electronic properties and about its formation upon excitation of aqueous systems by light are important to assess its role in radiation damage. Additionally, the influence of spatial confinement on those properties needs to be assessed. We have performed a series of experimental studies, revealing that spatial confinement has no major influence on the electronic properties nor on the relaxation dynamics of the hydrated electron. However, a clear system size dependence was observed for its probability of formation.
Because of the finite size of aerosol particles, sunlight is amplified in their interior. Our investigations show that all light-induced reaction steps in atmospheric aerosol particles will take place 2 to 3 times faster in these particles as a result of the light amplification - likely with important implications regarding the role of such light induced processes in atmospheric processes.