Novel Ultrafast X-ray Probes of Elementary Molecular Events

Novel X-ray pulse sources from free-electron lasers and high-harmonic generation setups enable the monitoring of molecular events on unprecedented temporal, spatial and energetic scales. The attosecond duration of X-ray pulses, their large bandwidth over a large tunable energy range, and the atomic selectivity of core X-ray excitations offer a uniquely high spatial and temporal selectivity for non-linear spectroscopies. In this talk, we survey recent theoretical developments that design, simulate, and predict spectroscopic signals revealing detailed information about ultrafast molecular dynamics. A special focus lies on the chirality of molecules and light. Resonant attosecond X-ray probes allow to monitor the dissociation of a single iodine atom from a chiral center. The loss of chiral information is distinctly visible in the transient signal, giving information about the timescale and distance across which chirality is experienced. From the light perspective, sophisticated spatio-temporal polarization profiles known from optical pulses is translated to X-ray wavelengths. We show how the Orbital Angular Momentum of X-ray light fields can be leveraged to detect coherences emerging at conical intersections due to the bifurcation of molecular wavepackets.