Abstract
The fragmentation dynamics of dicationic dimers of acetylene molecules initiated upon strong-field laser ionization is studied. Time-resolved pump-probe experiments with femtosecond laser pulses, accompanied by ab initio dynamical calculations, allow us to evaluate the detailed behavior of molecular ions during the dissociation process. The dynamical properties of the intermediate C2H2+⋯C2H2+ state created by the pump pulse are probed by a second pulse which causes further ionization. The time-dependent yield of a coincident C2H2+ + C2H22+ ion pair exhibits an oscillation feature with a periodicity of 240 ± 30 fs. Our studies demonstrate that this is caused by an ultrafast rotation of C2H2+ cations driven by intermolecular Coulomb force together with the orientation-dependent ionization rate. We suggest that the present observation of ultrafast molecular rotation can be a general phenomenon occurring in a wide variety of systems.Received 14 September 2020Accepted 31 March 2021DOI:https://doi.org/10.1103/PhysRevResearch.3.023050Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Open access publication funded by the Max Planck Society.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasLaser-cluster interactionUltrafast phenomenaVan der Waals interactionAtomic, Molecular & Optical
Highlights
Weak noncovalent or intermolecular interactions, such as hydrogen bonding and van der Waals forces, are significant in all realms of chemistry ranging from supramolecular sciences to chemical reactions [1,2,3,4,5,6]
Since the C2H2+ + C2H2+ Coulomb explosion is faster than the rotation of the dimer system, we determine experimentally the orientation of the intermolecular hydrogen bond by the emission direction of C2H2+ ionic fragments based on the axial recoil approximation [30]
We performed time-resolved experiments using strong-field femtosecond laser pulses to investigate the molecular dynamics in the dicationic acetylene dimer with two charges located separately
Summary
Weak noncovalent or intermolecular interactions, such as hydrogen bonding and van der Waals forces, are significant in all realms of chemistry ranging from supramolecular sciences to chemical reactions [1,2,3,4,5,6]. In recent years, studying the properties of excited states in weakly bound systems has attracted considerable interest due to the possibility for opening various ultrafast energy and charge transfer processes like the intermolecular Coulombic decay (ICD) [7]. In ICD, the innervalence vacancy is filled by an outer shell electron, and the energy released is transferred to neighboring molecules. This leads to ejection of a low-energy electron and formation of two repulsive ions at a distance of a few angstroms (Coulomb explosion). It has been shown that ICD is a very general phenomenon occurring after a manifold of excitation schemes and in numerous weakly bound systems (see, e.g., [8,9,10]). The importance of ICD as an efficient source of low-energy electrons has been widely recognized, both for fundamental reasons
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
