SAMOP 2023 – scientific programme
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A: Fachverband Atomphysik
A 34: Ultrafast Dynamics III (joint session MO/A)
A 34.4: Talk
Friday, March 10, 2023, 15:15–15:30, F102
Ultrafast dynamics in iodomethane induced by few-fs ultraviolet pulses — •Sergey Ryabchuk1,2, Lorenzo Colaizzi2,3, Erik P. Månsson3, Krishna Saraswathula3, Jesús González-Vázquez4, Vincent Wanie3, Andrea Trabattoni3,5, Fernando Martin4,6,7, and Francesca Calegari1,2,3 — 1The Hamburg Centre for Ultrafast Imaging, Hamburg, Germany — 2Universität Hamburg, Hamburg, Germany — 3DESY, Hamburg, Germany — 4Universidad Autonoma de Madrid, Madrid, Spain — 5Leibniz Universität Hannover, Hannover, Germany — 6IMDEA-Nanoscience, Madrid, Spain — 7IFIMAC, Madrid, Spain
Iodomethane has been extensively used as a model system to study photodissociation dynamics by ultraviolet (UV) light excitation. The molecule is prompted to rapid fragmentation along the C-I bond due to the repulsive character of the neutral states accessed by single UV photon absorption in the energy range of 4.1-5.4 eV. In this work, we used 4 fs UV pulses with central energy of 4.9 eV as a pump with delayed few-cycle infrared pulses, probing the dynamics via multi-photon ionization. The dynamics of methyl and iodine fragments allow us to track the field-free wavepacket evolution on the neutral states with unprecedented time resolution. Moreover, the experimental observations combined with a theoretical study revealed that the implementation of such ultrashort pulses allows for the production of an intact parent ion with a 5-fs lifetime, preventing molecular cleavage. This becomes possible only in a narrow time window close to the Frank-Condon regime before the dissociation takes place.