Heavy Rydberg behaviour in high vibrational levels of some ion-pair states of the halogens and inter-halogens

Resolving multiphoton processes with high-order anisotropy ultrafast X-ray scattering

We present the first results on experimentally measured ultrafast X-ray scattering of strongly driven molecular iodine and analysis of high-order anisotropic components of the scattering signal. We discuss the technical details of retrieving high fidelity high-order anisotropy components from the measured scattering data and outline a method to analyze such signals using Legendre decomposition. We describe how anisotropic motions can be extracted from the various Legendre orders using simulated anisotropic scattering signals and Fourier analysis. We implement the method on the measured signal and observe a multitude of dissociation and vibration motions simultaneously arising from various multiphoton transitions occurring in the sample. We use the anisotropic scattering information to disentangle the different processes and assign their dissociation velocities on the Angstrom and femtosecond scales de novo.

Heavy Rydberg states: large amplitude vibrations

Extremely large vibrational amplitude (≈8700 a.u.) heavy Rydberg levels in the HH[combining macron]1Σ+g state, located only 25 cm-1 below the ion-pair dissociation limit, are reported. The calculations are done using a hybrid log derivative/multichannel quantum defect approach that accounts for predissociation and is capable of dealing with any number of long-range closed channels, and of providing positions and widths for the heavy Rydberg resonances. In this case, resonance positions can be reproduced qualitatively using a simple diabatic model (however, the resonance widths cannot). Absolute quantum defects are derived for the vibrational series ranging from ν = 0 to ν = 2010. The influence of the Coulomb potential and continuity of heavy Rydberg behavior throughout the 1Σ+g manifold of states is demonstrated.

Highlights from the Faraday Discussion 296: quantum effects in small molecular systems, 10-12 September 2018, Edinburgh, United Kingdom

Exciting discussions on the impact of quantum effects in small molecular systems took place in the historical city of Edinburgh this fall 2018 in the unique conference format of the Faraday Discussions. During this three day conference meeting close to Holyrood Park, 65 leading experts from all over the world came together to discuss the developments, advances and challenges in the wide field of quantum effects in small molecular systems, either isolated or embedded into clusters, clathrates or cold matrices. The meeting clearly reflected the importance of the accurate description, characterization and prediction of quantum effects in isolated, solvated and complexed molecular systems, while allowing the community to crystallize future perspectives and directions in the field, as well as applications in chemistry, physics, biology, environmental sciences and industry.