A5035853136- Advanced Chemical Physics Studies
- Photochemistry and Electron Transfer Studies
- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Inorganic Fluorides and Related Compounds
- Laser-Matter Interactions and Applications
- Radical Photochemical Reactions
- Molecular Spectroscopy and Structure
- Photochromic and Fluorescence Chemistry
- DNA and Nucleic Acid Chemistry
- Organic Electronics and Photovoltaics
- Ammonia Synthesis and Nitrogen Reduction
- Chemistry and Chemical Engineering
- Quantum optics and atomic interactions
- Photodynamic Therapy Research Studies
- Catalysis and Oxidation Reactions
- Fluorine in Organic Chemistry
- Electron and X-Ray Spectroscopy Techniques
- Atmospheric chemistry and aerosols
- Organic Chemistry Cycloaddition Reactions
- GaN-based semiconductor devices and materials
- Molecular Junctions and Nanostructures
- Cold Atom Physics and Bose-Einstein Condensates
- Electron Spin Resonance Studies
- Spectroscopy and Laser Applications
University of East Anglia
2024-2025
KTH Royal Institute of Technology
2022-2024
Temple University
2017-2024
Temple College
2017-2020
Philadelphia University
2017-2020
Stony Brook University
2017
The development of new and improved photoswitches for photonic materials photo-pharmaceutics is an important research objective. Recently a family based on the rhodanine motif was described. In this work photophysics representative example that are investigated. photoswitch’s shown to be remarkably different to, more complex than, those observed closely related photoactive monomethines dyes, which typically relax in picoseconds by internal conversion. photoswitch allowed Franck-Condon...
We compare different levels of theory for simulating excited state molecular dynamics and use time-resolved photoelectron spectroscopy measurements to benchmark the theory. perform trajectory surface hopping simulations uracil first bright (ππ*) using three (CASSCF, MRCIS, XMS-CASPT2) in order understand role dynamical correlation determining dynamics, with a focus on coupling between electronic states internal conversion back ground state. These calculations are used simulate spectra. The...
Abstract Time‐resolved photoelectron spectroscopy is a powerful pump‐probe technique which can probe nonadiabatic dynamics in molecules. Interpretation of the experimental signals however requires input from theoretical simulations. Advances electronic structure theory, dynamics, and theory to calculate ionization yields, have enabled accurate simulation time‐resolved spectra leading successful applications technique. We review basic steps involved calculating spectra, highlight...
High level multi-reference non-adiabatic dynamics simulations reveal that uracil’s photoexcited S<sub>2</sub> state decays very quickly without any significant trapping.
Ionization can serve as a universal probe of excited-state dynamics in molecules, such internal conversion, dissociation, and isomerization. These processes are fundamental importance to wide array biology, chemistry, physics. In recent years, there has been significant debate about the relative merits strong-field ionization (SFI), which involves multiphoton absorption, versus weak-field (WFI), where single photon is absorbed, probes these dynamics. SFI advantageous because it uses...
We have performed trajectory surface hopping dynamics for cis,cis-1,3-cyclooctadiene to investigate the photochemical pathways involved after being excited S1 state. Our calculations reveal ultrafast decay ground state, facilitated by conical intersections involving distortions around double bonds. The main are localized on one bond, twisting and pyramidalization of carbons that bond (similar ethylene), while a limited number trajectories via delocalized (non-local) both interplay between...
An ultrafast electron diffraction study of the structural dynamics cis , -1,3-cyclooctadiene has identified a ring stretching distortion as new reaction coordinate molecule transitions from excited state back to ground state.
The mechanistic details of well-known photohydrate lesions are explored using state-of-the-art computational methods.
We present UV pump, vacuum ultraviolet probe time-resolved photoelectron spectroscopy measurements of the excited state dynamics cis,cis-1,3-cyclooctadiene. A 4.75 eV deep pump pulse launches a vibrational wave packet on first electronically state, and ensuing are probed via ionization using 7.92 pulse. The experimental results indicate that undergoes rapid internal conversion to ground in under 100 fs. Comparing with electronic structure trajectory surface hopping calculations, we able...
We study the relaxation dynamics of pyrrole after excitation with an 8 eV pump pulse to a state just 0.2 below ionization potential using vacuum ultraviolet/ultraviolet probe spectroscopy. Our measurements in conjunction electronic structure calculations indicate that undergoes rapid internal conversion ground less than 300 fs. find dominates over dissociation.
We perform time-resolved UV pump (4.77 eV) and VUV probe (7.94 measurements of internal conversion 1,3-cyclohexadiene (CHD). Our reveal a substantial ionization the ``hot'' ground state following despite fact that our photon energy is below potential (8.21 eV). With aid electronic structure calculations, we interpret results in terms vibrationally assisted below-threshold ionization, where vibrational converted to energy. The effect relies on both having modes which allow for this...
Chemical substituents can influence photodynamics by altering the location of critical points and topography potential energy surface (electronic effect) selectively inertia specific nuclear modes (inertial effects). Using non-adiabatic dynamics simulations, we investigate impact methylation on S2(pp*) internal conversion in acrolein – simplest linear alpha,beta-unsaturated carbonyl. Consistent with time constants reported a previous time-resolved photoelectron spectroscopy study,...
Chemical substituents can influence photodynamics by altering the location of critical points and topography potential energy surfaces (electronic effect) selectively modifying inertia specific nuclear modes (inertial effects). Using nonadiabatic dynamics simulations, we investigate impact methylation on S2(ππ*) internal conversion in acrolein, simplest linear α,β-unsaturated carbonyl. Consistent with time constants reported a previous time-resolved photoelectron spectroscopy study, S2 → S1...
We compare time resolved photoelectron spectroscopy measurements and trajectory surface hopping calculations for 1,3 - Cyclohexadiene (CHD) cis,cis-1,3 Cyclooctadiene (COD). find qualitative agreement between experiment theory both but quantitative only CHD.