Direct mapping of curve-crossing dynamics in IBr by attosecond transient absorption spectroscopy

Kobayashi, Yuki; Chang, Kristina F.; Zeng, Tao; Neumark, Daniel M.; Leone, Stephen R.

doi:10.1126/science.aax0076

Cited by 121 publications

(96 citation statements)

References 61 publications

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“…ATAS can probe valence electrons through excitation to high-lying electronic states 1–14 . ATAS can also excite core-level electrons to reveal molecular structure using techniques such as near-edge X-ray absorption fine structure (NEXAFS) 15–18 , for example around the carbon K-edge at 284 eV. Pump-probe type experiments in which two-photon processes are driven by a combination of an attosecond pulse and an infrared pulse have revealed coupling between states and the production of light-induced states 4,7 .…”

Section: Introductionmentioning

confidence: 99%

Symmetry of molecular Rydberg states revealed by XUV transient absorption spectroscopy

et al. 2019

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Transient absorption spectroscopy is utilized extensively for measurements of bound- and quasibound-state dynamics of atoms and molecules. The extension of this technique into the extreme ultraviolet (XUV) region with attosecond pulses has the potential to attain unprecedented time resolution. Here we apply this technique to aligned-in-space molecules. The XUV pulses are much shorter than the time during which the molecules remain aligned, typically 100 fs. However, transient absorption is not an instantaneous probe, because long-lived coherences re-emit for picoseconds to nanoseconds. Due to dephasing of the rotational wavepacket, it is not clear if these coherences will be evident in the absorption spectrum, and whether the properties of the initial excitations will be preserved. We studied Rydberg states of N and O from 12 to 23 eV. We were able to determine the polarization direction of the electronic transitions, and hence identify the symmetry of the final states.

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Section: Introductionmentioning

confidence: 99%

Symmetry of molecular Rydberg states revealed by XUV transient absorption spectroscopy

et al. 2019

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“…These results are in line with the interpretation that the corelevel absorption is not simply probing the potential energies; instead, it is a direct probe of the valence orbital character and electronic configurations, the latter abruptly changing at the avoided crossing. 15 Overall, ultrafast XUV transient absorption spectroscopy will provide powerful and complementary windows into the predissociation dynamics, and we foresee its wider applications to molecular dynamics that involve elusive potential crossings.…”

Section: Discussionmentioning

confidence: 99%

“…59 A recent experimental work confirmed the SO-GMC-QDPT results can reproduce the core-level absorption spectra throughout the reaction coordinates with these manual settings. 15 Spectroscopic parameters of the valence potentials are analyzed to evaluate the accuracy of the calculation results. For the ground X(0 + ) state, the equilibrium internuclear distance and harmonic frequency are calculated to be 2.75Å and 250.9 cm −1 , respectively, which compare well with the experimental values of 2.71Å and 259.2 cm −1 .…”

Section: A Electronic-structure Calculationsmentioning

confidence: 99%

“…13 Of particular importance is the ability to directly probe avoided crossings and conical intersections, where two or more reaction potentials come to degeneracy (or pseudodegeneracy) and start to couple nonadiabatically. 14,15 The coupling can induce photoexcited molecules to undergo nonadiabatic population transfer or rapidly a) Electronic mail: ykoba@berkeley.edu switch their electronic character between the coupled states. [16][17][18][19][20] Those elusive processes have been a subject of numerous spectroscopic studies for their ubiquitous role in steering the outcome of photochemical reactions.…”

Section: Introductionmentioning

confidence: 99%

“…[16][17][18][19][20] Those elusive processes have been a subject of numerous spectroscopic studies for their ubiquitous role in steering the outcome of photochemical reactions. 15,[21][22][23][24][25][26][27][28][29][30][31][32][33][34] Despite the established concept of potential crossings, their experimental observation is still considered challenging, as it requires few-femtosecond time resolution and a capability to resolve closely-spaced electronic states by the probe method.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

NaI revisited: Theoretical investigation of predissociation via ultrafast XUV transient absorption spectroscopy

Kobayashi

Zeng

Neumark

et al. 2019

The Journal of Chemical Physics

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Avoided crossings can trigger abrupt changes of electronic character and redirect the outcomes of photochemical reactions. Here, we report a theoretical investigation into core-level spectroscopic probing of predissociation dynamics of sodium iodide (NaI), a prototype system for studies of avoided-crossing dynamics. The elegant femtochemistry work of Zewail and co-workers pioneered the real-time dynamics of NaI, detecting the Na atoms bursting forth from the avoided crossing and the residual NaI molecules oscillating inside the quasi-bound potential. The simulated results show that core-level spectroscopy not only observes these integrated outcomes, but also provides a direct measure of the abrupt switching of electronic character at the avoided crossing. The valence and core-excited electronic structures of NaI are computed by spin-orbit general multi-configurational quasi-degenerate perturbation theory, from which core-level absorption spectra of the predissociation dynamics are constructed. The wave-packet motion on the covalent potential is continuously mapped as shifts in the absorption energies, and the switching between the covalent and ionic character at the avoided crossing is characterized as the sharp rise and fall of the Na + signal. The Na + signal is found to be insensitive to the wave-packet motion in the asymptotic part of the ionic potential, which in turn enables a direct measure of the nonadiabatic crossing probability excluding the effect of wave-packet broadening.

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Vibronic Dynamics of Photodissociating ICN from Simulations of Ultrafast X‐Ray Absorption Spectroscopy

et al. 2020

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Ultrafast UV-pump/soft-X-ray-probe spectroscopy is as ubject of great interest since it can provide detailed information about dynamical photochemical processes with ultrafast resolution and atomic specificity.H ere,w ef ocus on the photodissociation of ICN in the 1 P 1 excited state,w ith emphasis on the transient response in the soft-X-ray spectral region as described by the ab initio spectral lineshape averaged over the nuclear wavepacket probability density.W ef ind that the carbon K-edge spectral region reveals ar ich transient response that provides direct insights into the dynamics of frontier orbitals during the I À CN bond cleavage process.T he simulated UV-pump/soft-X-ray-probe spectra exhibit detailed dynamical information, including atime-domain signature for coherent vibration associated with the photogenerated CN fragment.

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Direct mapping of curve-crossing dynamics in IBr by attosecond transient absorption spectroscopy

Cited by 121 publications

References 61 publications

Symmetry of molecular Rydberg states revealed by XUV transient absorption spectroscopy

Symmetry of molecular Rydberg states revealed by XUV transient absorption spectroscopy

NaI revisited: Theoretical investigation of predissociation via ultrafast XUV transient absorption spectroscopy

Vibronic Dynamics of Photodissociating ICN from Simulations of Ultrafast X‐Ray Absorption Spectroscopy

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