Physics

Electron

Ultrafast electron diffraction

Laser

Intersection (aeronautics)

Optics

Conical surface

Excited state

Atomic physics

Composite material

Geography

Diffraction

Ultrashort pulse

Nuclear physics

Chemistry

Materials science

Conical intersection

Cartography

Electron diffraction

Photodissociation

Photochemistry

Science

Conical intersections play a critical role in excited-state dynamics of polyatomic molecules because they govern the reaction pathways of many nonadiabatic processes. However, ultrafast probes have lacked sufficient spatial resolution to image wave-packet trajectories through these intersections directly. Here, we present the simultaneous experimental characterization of one-photon and two-photon excitation channels in isolated CF3I molecules using ultrafast gas-phase electron diffraction. In the two-photon channel, we have mapped out the real-space trajectories of a coherent nuclear wave packet, which bifurcates onto two potential energy surfaces when passing through a conical intersection. In the one-photon channel, we have resolved excitation of both the umbrella and the breathing vibrational modes in the CF3 fragment in multiple nuclear dimensions. These findings benchmark and validate ab initio nonadiabatic dynamics calculations.

Imaging CF <sub>3</sub> I conical intersection and photodissociation dynamics with ultrafast electron diffraction

Imaging CF 3 I conical intersection and photodissociation dynamics with ultrafast electron diffraction

Imaging CF ₃ I conical intersection and photodissociation dynamics with ultrafast electron diffraction