Monitoring the evolution of relative product populations at early times during a photochemical reaction

Abstract

Identifying multiple rival reaction products and transient species formed during ultrafast photochemical reactions and determining their time-evolving relative populations are key steps towards understanding and predicting photochemical outcomes. Yet, most contemporary ultrafast studies struggle with clearly identifying and quantifying competing molecular structures/species amongst the emerging reaction products. Here, we show that mega-electronvolt ultrafast electron diffraction in combination with ab initio molecular dynamics calculations offer a powerful route to determining time-resolved populations of the various isomeric products formed after UV (266 nm) excitation of the five-membered heterocyclic molecule 2(5H)-thiophenone. This strategy provides experimental validation of the predicted high (~50%) yield of an episulfide isomer containing a strained 3-membered ring within ~1 ps of photoexcitation and highlights the rapidity of interconversion between the rival highly vibrationally excited photoproducts in their ground electronic state.

References in corpus (2)

• Time-resolved photoelectron spectroscopy of non-adiabatic dynamics in polyatomic molecules
• Conformer-specific Chemistry Imaged in Real Space and Time

Cited by in corpus (3)

• 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
• Retrieval of missing small-angle scattering data in gas-phase diffraction experiments
• Ultrafast electron diffractive imaging of the dissociation of pre-excited molecules