Diffractive imaging of dissociation and ground-state dynamics in a complex molecule

Authors

Kyle J. Wilkin, University of Nebraska–LincolnFollow
Robert M. Parrish, SLAC National Accelerator Laboratory
Jie Yang, SLAC National Accelerator Laboratory
Thomas J.A. Wolf, Stanford University
J. Pedro F. Nunes, University of Nebraska–Lincoln
Markus Guehr, Stanford University
Renkai Li, SLAC National Accelerator Laboratory
Xiaozhe Shen, SLAC National Accelerator Laboratory
Qiang Zheng, SLAC National Accelerator Laboratory
Xijie Wang, SLAC National Accelerator Laboratory
Todd J. Martinez, Stanford University
Martin Centurion, University of Nebraska - LincolnFollow

Document Type

Article

Date of this Version

8-2-2019

Citation

PHYSICAL REVIEW A 100, 023402 (2019)

DOI: 10.1103/PhysRevA.100.023402

Comments

©2019 American Physical Society. Used by permission.

Abstract

We have investigated the structural dynamics in photoexcited 1,2-diiodotetrafluoroethane molecules (C₂F₄I₂) in the gas phase experimentally using ultrafast electron diffraction and theoretically using FOMO-CASCI excited-state dynamics simulations. The molecules are excited by an ultraviolet femtosecond laser pulse to a state characterized by a transition from the iodine 5p orbital to a mixed 5p||σ hole and CF₂• antibonding orbital, which results in the cleavage of one of the carbon-iodine bonds. We have observed, with sub-Angstrom resolution, the motion of the nuclear wave packet of the dissociating iodine atom followed by coherent vibrations in the electronic ground state of the C₂F₄I radical. The radical reaches a stable classical (nonbridged) structure in less than 200 fs.