Grant: Discovery Grants Program - Individual

Today we have incredible control over the optical fields created by lasers, both in time and in space. We can control the color, polarization and duration of laser pulses. We can combine nearly arbitrary frequencies and pulse durations. We can control the spatial properties of the light within the laser beam. For example we can create beams with a hole in the middle, beams with a spatially varying polarization vector, or beams whose wave front looks like a corkscrew in space. This degree of control over laser fields opens up new applications, some of which I will explore. While circularly polarized laser fields are chiral their wavelength is generally much larger than a single molecule, i.e., away from resonances a molecule experiences only a homogeneous electric field. I propose to realize a laser field that is chiral at every point in space and that will permit to distinguish left and right-handed molecules much more efficiently than commonly used methods such as photoelectron circular dichroism. I will use coincidence photoelectron photoion momentum spectroscopy, known as COLTRIMS or reaction microscopy, to detect a chirality dependent signal in ionization yields, photoelectron molecular frame angular distribution and Coulomb explosion imaging. In addition to developing a new structural diagnostic tool, I propose to excite and image ultrafast relaxation processes in water. Water dimers as the simplest approximation to liquid water can serve as testing ground to understand the processes that are initiated by high energy photons. Soft X-ray absorption in water is understood poorly despite its paramount importance in different fields. Understanding the energy and charge redistribution on X-ray photon absorption in water is vital for the design of more-efficient radiooncology schemes, for disentangling the physical basis of genotoxic effects on living tissues and for minimizing the damage of biological samples during X-ray diffraction experiments. Both projects provide ample opportunity for expansion and future research.