Dynamics of highly-ionised Diiodomethane: Coulomb Explosion, Energy Exchange and Rotating Fragments
Abstract The dissociation dynamics of diiodomethane molecules (CH2I2) have been investigated following absorption of 98 eV XUV photons. In the measurement at the reaction microscope endstation at the free-electron laser FLASH2, ionic fragments created by 4d core ionisation followed by Auger decay have been detected in coincidence. In the one-photon absorption channel CH2+ / I+ / I+, a concerted three-ion breakup and a sequential dissociation via a rotating intermediate CH2I++ ion have been identified. Classical simulations based on a Coulomb repulsion model and ab initio molecular dynamics in the frame of the Density Functional Theory have been performed. Both types of simulations reproduce different aspects of the observed fragmentation dynamics, in particular a delayed second bond break after dissociation of the first iodine ion. In the study of the potential energy surface we have located a minimum after the emission of the first I+. We attribute the sequential mechanism to the trapping of the rotationally excited CH2I++ fragment in this transient intermediate, which corresponds to a potential energy well that protects it against the cleavage of the second C-I bond.
Authors
- Sergio Díaz‐Tendero (ORCID: https://orcid.org/0000-0001-6253-6343)
- Florian Trost (ORCID: https://orcid.org/0000-0001-7756-286X)
- Kirsten Schnorr (ORCID: https://orcid.org/0000-0002-5519-440X)
- Patrizia Schoch (ORCID: https://orcid.org/0000-0003-1462-4589)
- Sven Augustin (ORCID: https://orcid.org/0000-0003-1283-331X)
- R. Guillemin (ORCID: https://orcid.org/0000-0001-9239-7372)
- Markus Braune (ORCID: https://orcid.org/0000-0002-2091-4585)
- Severin Meister (ORCID: https://orcid.org/0000-0002-5245-8377)
- G. J. Schmid
- Farzad Hosseini (ORCID: https://orcid.org/0000-0002-1353-1068)
- Hannes Lindenblatt (ORCID: https://orcid.org/0000-0003-1728-7979)
- Fernando Martı́n (ORCID: https://orcid.org/0000-0002-7529-925X)
- Moustafa Zmerli (ORCID: https://orcid.org/0000-0002-6798-8119)
- R. Moshammer (ORCID: https://orcid.org/0000-0002-3666-4904)
- Yifan Liu (ORCID: https://orcid.org/0000-0002-9044-0936)
- Thomas Pfeifer
- Marc Simon
- MariaNovella Piancastelli
- Claus Dieter Schroeter
Institutions
- Madrid Institute for Advanced Studies (ES)
- Centre National de la Recherche Scientifique (FR)
- Deutsches Elektronen-Synchrotron DESY (DE)
- Paul Scherrer Institute (CH)
- Sorbonne Université (FR)
- Laboratoire de Chimie Physique - Matière et Rayonnement (FR)
- Max Planck Institute for Nuclear Physics (DE)
- Universidad Autónoma de Madrid (ES)
Publication Details
- Journal
- Journal of Physics B Atomic Molecular and Optical Physics
- Published
- 2025-04-04
- DOI
- https://doi.org/10.1088/1361-6455/adc963
- Primary Topic
- High-pressure geophysics and materials
- Type
- article
- Field-Weighted Citation Impact
- 0.00