A5083453279- Laser-Matter Interactions and Applications
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Atomic and Molecular Physics
- Photoreceptor and optogenetics research
- Spectroscopy Techniques in Biomedical and Chemical Research
- Photochemistry and Electron Transfer Studies
- Spectroscopy and Laser Applications
- Electron and X-Ray Spectroscopy Techniques
- Luminescence and Fluorescent Materials
- Crystallography and molecular interactions
- Quantum optics and atomic interactions
- Boron Compounds in Chemistry
- Molecular spectroscopy and chirality
- X-ray Spectroscopy and Fluorescence Analysis
- Ocular and Laser Science Research
- Electron Spin Resonance Studies
- Spectroscopy and Chemometric Analyses
- Atomic and Subatomic Physics Research
- Laser-Plasma Interactions and Diagnostics
- Radiopharmaceutical Chemistry and Applications
- Advanced Electron Microscopy Techniques and Applications
- Radioactive element chemistry and processing
- Ion-surface interactions and analysis
Kansas State University
2020-2025
University of Science and Technology of China
2024
Augustana University
2020
Coulomb explosion imaging (CEI) with x-ray free electron lasers has recently been shown to be a powerful method for obtaining detailed structural information of gas-phase planar ring molecules [R. Boll et al. Nat. Phys. 18, 423-428 (2022)]. In this Letter, we investigate the potential CEI driven by tabletop laser and extend approach differentiating three-dimensional (3D) structures. We study static patterns nonplanar organic that resemble structures typical products formed in ring-opening...
We investigated the ultrafast structural dynamics of cyclobutanone following photoexcitation at $\lambda=200$ nm using gas-phase megaelectronvolt electron diffraction. Our investigation complements simulation studies same process within this special issue. It provides information about both electronic state population and through well-separable inelastic elastic scattering signatures. observe depopulation photoexcited S$_2$ with n3s Rydberg character its signature a time constant $(0.29 \pm...
Abstract The photochemistry of heterocyclic molecules plays a decisive role for processes and applications like DNA photo-protection from UV damage organic photocatalysis. photochemical reactivity heterocycles is determined by the redistribution photoenergy into electronic nuclear degrees freedom, initially involving ultrafast internal conversion. Most are planar in their ground state conversion requires symmetry breaking. To lower symmetry, molecule must undergo an out-of-plane motion,...
The absolute photoabsorption cross sections of norbornadiene (NBD) and quadricyclane (QC), two isomers with chemical formula C7H8 that are attracting much interest for solar energy storage applications, have been measured from threshold up to 10.8 eV using the Fourier transform spectrometer at SOLEIL synchrotron radiation facility. absorption spectrum NBD exhibits some sharp structure associated transitions into Rydberg states, superimposed on several broad bands attributable valence...
The angle-dependent single ionization of carbon dioxide by linearly and circularly polarized pulses is investigated experimentally. authors show that delay-dependent ion-momentum measurements from rotational wave packets can be used to test the validity axial recoil approximation.
C-I bond extension and fission following ultraviolet (UV, 262 nm) photoexcitation of 2- 3-iodothiophene is studied using ultrafast time-resolved extreme (XUV) ionization in conjunction with velocity map ion imaging. The photoexcited molecules eventual I atom products are probed by site-selective at the 4d edge intense XUV pulses, which induce multiple charges initially localized to iodine atom. At separations below critical distance for charge transfer (CT), can redistribute around molecule...
Using the CD3OH isotopologue of methanol, ratio D2H+ to D3+ formation is manipulated by changing characteristics intense femtosecond laser pulse. Detection indicates a process involving two hydrogen atoms from methyl side molecule and proton hydroxyl side, while detection local only group. Both mechanisms are thought involve neutral D2 moiety. An adaptive control strategy that employs image-based feedback guide learning algorithm results in an enhancement D2H+/D3+ factor approximately two....
We probe the time-dependent ionization dynamics of impulsively excited rotational wave packets ${\mathrm{N}}_{2}, {\mathrm{CO}}_{2}$, and ${\mathrm{C}}_{2}{\mathrm{H}}_{4}$ using broadband ultraviolet pulses centered at 262 nm. Photoelectron momentum distributions recorded by velocity-map imaging show a strong dependence on alignment, multiphoton order, electronic vibrational states cation. that substantial information about molecular-frame photoelectron angular distribution can be obtained...
We have studied the fragmentation of brominated cyclic hydrocarbons bromocyclo-propane, bromocyclo-butane, and bromocyclo-pentane upon Br(3d) C(1s) inner-shell ionization using coincidence ion momentum imaging. observe a substantial yield CH3+ fragments, whose formation requires intramolecular hydrogen (or proton) migration, that increases with molecular size, which contrasts prior observations migration in linear hydrocarbon molecules. Furthermore, by inspecting fragment correlations...
Using strong-field ionization as a probe, we observe highly nonperiodic evolution of the spin-rotation wave packet launched by nonionizing femtosecond pulse in oxygen. The nonperiodicity is readily apparent only rotationally cold molecules that are pumped with weak alignment pulse. We show this behavior consequence and spin-spin couplings triplet ground state neutral molecule. A model includes these field-free Hamiltonian but neither nor step explains most observed dynamics, suggesting...
Molecular photoabsorption results in an electronic excitation/ionization which couples to the rearrangement of nuclei. The resulting intertwined change nuclear and degrees freedom determines conversion photoenergy into other molecular energy forms. Nucleobases are excellent candidates for studying such dynamics, great effort has been taken past observe changes induced by initial excitation a time-resolved manner using ultrafast electron spectroscopy. linked geometrical during nucleobase...
<title>Abstract</title> Photoinduced transformations of organic ring molecules play a crucial role in numerous physical, chemical and biological processes, ranging from biosynthesis vitamin D to optical switching molecular electronics. Although the development plethora ultrafast techniques such as time-resolved photoelectron spectroscopy, electron x-ray diffraction transient absorption has recently enabled detailed investigations electronic nuclear dynamics several conversion reactions,...
Vibrational Cooper minima due to weak dipole coupling were previously observed in strong-field dissociation of ${\mathrm{H}}_{2}{}^{+}$ as the kinetic-energy-release (KER) spectrum [McKenna et al., Phys. Rev. Lett. 103, 103006 (2009)]. We demonstrate two independent experiments that these vibrational occur more generally and can be used ``fingerprints'' identify final electronic state pathway. In first experiment, we show wavelength dependence KER ${\mathrm{O}}_{2}{}^{+}$ induced by 396-...
We present a time-resolved measurement of the photodissociation and photoisomerization dynamics bromoform (CHBr3) in mono- di-cationic states produced by near-infrared (NIR) strong-field ionization. The dissociation process is probed NIR-induced Coulomb explosion imaging. find that for channels involving production HBr Br2 fragments, which require formation new bonds, appears to be delayed with respect primary C–Br bond channel. Ab initio molecular simulations support observed delay....
Molecular dynamics triggered by interaction with light often involve the excitation of several electronic, vibrational, and rotational states. Characterizing resulting coupled electronic nuclear wave packet motion represents a severe challenge, even for small polyatomic systems. In this Letter, we demonstrate how interplay between rotational, degrees freedom governs evolution molecular packets in low-lying states strong-field-ionized sulfur dioxide. Using time-resolved Coulomb explosion...
We present results of classical Coulomb explosion simulations to demonstrate that imaging can serve as a robust method for differentiating molecular structures and following structural changes in pump-probe experiments by tracking the motion individual atoms within molecule.
Following the changes in molecular structure throughout entirety of a chemical reaction with atomic resolution is long-term goal femtochemistry. Although development plethora ultrafast technique has enabled detailed investigations electronic and nuclear dynamics on femtosecond time scales, direct unambiguous imaging motion during still major challenge. Here, we apply time-resolved Coulomb explosion near-infrared pulses to visualize ultraviolet-induced gas-phase furan. Widely contradicting...
The 53rd Annual Meeting of the APS Division Atomic, Molecular and Optical Physics will take place from May 30 – June 3, 2022 in Orlando, Fl, USA. <a href="https://morressier.zoom.us/j/89880865272?pwd=SWxTRGhra1ZOSDBrSkhVZDBzVDR6UT09/">Virtual Presenter Help Desk</a>
The 53rd Annual Meeting of the APS Division Atomic, Molecular and Optical Physics will take place from May 30 – June 3, 2022 in Orlando, Fl, USA. <a href="https://morressier.zoom.us/j/89880865272?pwd=SWxTRGhra1ZOSDBrSkhVZDBzVDR6UT09/">Virtual Presenter Help Desk</a>