Imaging the Photochemical Ring-Opening of 1,3-Cyclohexadiene by Ultrafast Electron Diffraction

Abstract

The ultrafast photoinduced ring-opening of 1,3-cyclohexadiene constitutes a textbook example of electrocyclic reactions in organic chemistry and a model for photobiological reactions in vitamin D synthesis. Here, we present direct and unambiguous observation of the ring-opening reaction path on the femtosecond timescale and sub-Ångström length scale by megaelectronvolt ultrafast electron diffraction. We follow the carbon-carbon bond dissociation and the structural opening of the 1,3-cyclohexadiene ring by direct measurement of time-dependent changes in the distribution of interatomic distances. We observe a substantial acceleration of the ring-opening motion after internal conversion to the ground state due to steepening of the electronic potential gradient towards the product minima. The ring-opening motion transforms into rotation of the terminal ethylene groups in the photoproduct 1,3,5-hexatriene on the sub-picosecond timescale. Our work demonstrates the potential of megaelectronvolt ultrafast electron diffraction to elucidate photochemical reaction paths in organic chemistry.

References in corpus (4)

• X-ray diffraction from isolated and strongly aligned gas-phase molecules with a free-electron laser
• Probing ultrafast ππ*/nπ* internal conversion in organic chromophores via K-edge resonant absorption
• Diffractive Imaging of Coherent Nuclear Motion in Isolated Molecules
• Diffractive imaging of a molecular rotational wavepacket with femtosecond Megaelectronvolt electron pulses

Cited by in corpus (38)

• Achieving 50 femtosecond resolution in MeV ultrafast electron diffraction with a double bend achromat compressor
• Visualizing Conical Intersection Passages via Vibronic Coherence Maps Generated by Stimulated Ultrafast X--Ray Raman Signals
• Conformer-specific Chemistry Imaged in Real Space and Time
• Roadmap for Molecular Benchmarks in Nonadiabatic Dynamics
• Diffractive imaging of dissociation and ground state dynamics in a complex molecule
• Molecular structure retrieval directly from laboratory-frame photoelectron spectra in laser-induced electron diffraction
• Excited Electronic States in Total Isotropic Scattering From Molecules
• Quantum state tomography of molecules by ultrafast diffraction
• Non-Adiabatic Electronic and Vibrational Ring-Opening Dynamics resolved with Attosecond Core-Level Spectroscopy
• Rehybridization dynamics into the pericyclic minimum of an electrcyclic reaction imaged in real-time
• Environmental effects with Frozen Density Embedding in Real-Time Time-Dependent Density Functional Theory using localized basis functions
• Monitoring the evolution of relative product populations at early times during a photochemical reaction
• Predicting the photodynamics of cyclobutanone triggered by a laser pulse at 200 nm and its MeV-UED signals -- a trajectory surface hopping and XMS-CASPT2 perspective
• Imaging an isolated water molecule using a single electron wave packet
• Using a multistate Mapping Approach to Surface Hopping to predict the Ultrafast Electron Diffraction signal of gas-phase cyclobutanone
• Theory on polarization-averaged core-level molecular-frame photoelectron angular distributions: II. Extracting the X-ray induced fragmentation dynamics of carbon monoxide dication from forward and backward intensities
• Imaging the photochemical dynamics of cyclobutanone with MeV ultrafast electron diffraction
• Multi-Objective Bayesian Active Learning for MeV-ultrafast electron diffraction
• High-Energy Molecular-Frame Photoelectron Angular Distributions: A Molecular Bond-Length Ruler
• Prediction of Photodynamics of 200 nm Excited Cyclobutanone with Linear Response Electronic Structure and Ab Initio Multiple Spawning
• Quantum interference and imaging using intense laser fields
• Real-Space Inversion and Super-Resolution of Ultrafast Scattering
• Prediction challenge: First principles simulation of the ultrafast electron diffraction spectrum of cyclobutanone
• Robust inversion of time-resolved data via forward-optimisation in a trajectory basis
• Classical and quantum light-induced non-adiabaticity in molecular systems
• Non-invasive time-sorting in radio-frequency compressed ultrafast electron diffraction
• Imaging valence electron rearrangement in a chemical reaction using hard X-ray scattering
• Coulomb blockade in field electron emission from carbon nanotubes
• Ultrafast Photochemistry and Electron Diffraction for Cyclobutanone in the S2 State: Surface Hopping with Time-Dependent Density Functional Theory
• Simulating Ultrafast Transient Absorption Spectra from First Principles using a Time-Dependent Configuration Interaction Probe
• Super-resolution femtosecond electron diffraction reveals electronic and nuclear dynamics at conical intersections
• Vibronic fine structure in the nitrogen 1s photoelectron spectra from Franck-Condon simulations II: Indoles
• A Laboratory Frame Density Matrix for Ultrafast Quantum Molecular Dynamics
• Applying Bayesian Inference and deterministic anisotropy to retrieve the molecular structure $|\Psi (\mathbf{R}){|}^2$ distribution from gas-phase diffraction experiments
• A comparison of partial atomic charges for electronically excited states
• Time-resolving the UV-initiated photodissociation dynamics of OCS
• Ultrafast Electron Diffraction: Visualizing Dynamic States of Matter
• Variational Density Functional Calculations of Excited States: Conical Intersection and Avoided Crossing in Ethylene Bond Twisting