Structural dynamics effects on the ultrafast chemical bond cleavage of a photodissociation reaction

The correlation between chemical structure and dynamics has been explored in a series of molecules with increasing structural complexity in order to investigate its influence on bond cleavage reaction times in a photodissociation event. Femtosecond time-resolved velocity map imaging spectroscopy reveals specificity of the ultrafast carbon–iodine (C–I) bond breakage for a series of linear (unbranched) and branched alkyl iodides, due to the interplay between the pure reaction coordinate and the rest of the degrees of freedom associated with the molecular structure details. Full-dimension time-resolved dynamics calculations support the experimental evidence and provide insight into the structure–dynamics relationship to understand structural control on time-resolved reactivity

Structural dynamics effects on the ultrafast chemical bond cleavage of a photodissociation reaction

The correlation between chemical structure and dynamics has been explored in a series of molecules with increasing structural complexity in order to investigate its influence on bond cleavage reaction times in a photodissociation event. Femtosecond time-resolved velocity map imaging spectroscopy reveals specificity of the ultrafast carbon–iodine (C–I) bond breakage for a series of linear (unbranched) and branched alkyl iodides, due to the interplay between the pure reaction coordinate and the rest of the degrees of freedom associated with the molecular structure details. Full-dimension time-resolved dynamics calculations support the experimental evidence and provide insight into the structure–dynamics relationship to understand structural control on time-resolved reactivityMICINNEuropean Union ITNDepto. de Química FísicaFac. de Ciencias QuímicasTRUEpu

Dynamic Stark shift of the³<i>R</i>₁Rydberg state of CH₃I

Depto. de Química FísicaFac. de Ciencias QuímicasTRUEpu

Encoding of vinylidene isomerization in its anion photoelectron spectrum

Vinylidene-acetylene isomerization is the prototypical example of a 1,2-hydrogen shift, one of the most important classes of isomerization reactions in organic chemistry. This reaction was investigated with quantum state specificity by high-resolution photoelectron spectroscopy of the vinylidene anions H2CCˉ and D2CCˉ and quantum dynamics calculations. Peaks in the photoelectron spectra are considerably narrower than in previous work and reveal subtleties in the isomerization dynamics of neutral vinylidene, as well as vibronic coupling with an excited state of vinylidene. Comparison with theory permits assignment of most spectral features to eigenstates dominated by vinylidene character. However, excitation of the ν6 in-plane rocking mode in H2CC results in appreciable tunneling-facilitated mixing with highly vibrationally excited states of acetylene, leading to broadening and/or spectral fine structure that is largely suppressed for analogous vibrational levels of D2CCThe experimental part of this research was funded by the Air Force Office of Scientific Research (FA9550-16-1-0097 to D.M.N.) and the Australian Research Council Discovery Project (DP160102585 to S.T.G.). M.L.W. thanks the National Science Foundation for a graduate research fellowship. Experimental data are available in the supplementary materials. Theoretical work was funded by the National Natural Science Foundation of China (91441107 to J.M.), the Air Force Office of Scientific Research (FA9550-15-1- 0305 to H.G.), and the National Science Foundation (CHE-1361121 to D.R.Y.). R.W.F. gratefully acknowledges the Department of Energy, Office of Science, Chemical Sciences Geosciences and Biosciences Division of the Basic Energy Sciences Office (DE-FG0287ER13671). W.C.L. thanks the National Science Foundation JILA Physics Frontier Center (PHY1128544), and G.B. acknowledges the Spanish Ministry of Economy and Competitiveness (EEBB-I-16-11350 and BES-2013-063562)

Encoding of vinylidene isomerization in its anion photoelectron spectrum

inylidene-acetylene isomerization is the prototypical example of a 1,2-hydrogen shift, one of the most important classes of isomerization reactions in organic chemistry. This reaction was investigated with quantum state specificity by high-resolution photoelectron spectroscopy of the vinylidene anions H₂CCˉ and D₂CCˉ and quantum dynamics calculations. Peaks in the photoelectron spectra are considerably narrower than in previous work and reveal subtleties in the isomerization dynamics of neutral vinylidene, as well as vibronic coupling with an excited state of vinylidene. Comparison with theory permits assignment of most spectral features to eigenstates dominated by vinylidene character. However, excitation of the ν₆ in-plane rocking mode in H₂CC results in appreciable tunneling-facilitated mixing with highly vibrationally excited states of acetylene, leading to broadening and/or spectral fine structure that is largely suppressed for analogous vibrational levels of D₂CC.United States. Department of Energy. Office of Basic Energy Sciences (Award DE-FG0287ER13671)