Bulletin of the American Physical Society
54th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 68, Number 7
Monday–Friday, June 5–9, 2023; Spokane, Washington
Session K03: Ultrafast Dynamics in the Condensed PhaseInvited Live Streamed
|
Hide Abstracts |
Chair: Adi Natan, SLAC National Accelerator Laboratory Room: Ballroom 111 B |
Wednesday, June 7, 2023 10:30AM - 11:00AM |
K03.00001: High-order harmonic generation from a dielectric in the presence of a quasi-static field Invited Speaker: Louis F DiMauro Studies of laser-driven strong field processes subjected to a (quasi-)static field have |
Wednesday, June 7, 2023 11:00AM - 11:30AM |
K03.00002: High-harmonic spectroscopy in solids: multiband effects and anomalous currents Invited Speaker: Lun Yue High-harmonic generation (HHG) has emerged in recent years as an all-optical probe of ultrafast dynamics and static properties of materials. Here, I report on our recent work on spectroscopic applications of HHG. |
Wednesday, June 7, 2023 11:30AM - 12:00PM |
K03.00003: Bridging the phase gap: directly comparing ultrafast dynamics in the gas and liquid phases Invited Speaker: Hans Jakob Wörner Directly contrasting ultrafast dynamics of molecules in gas and liquid phases is crucial to understanding the influence of complex environments on (photo-)chemical processes. However, such direct comparisons have long remained out of reach because of a lack of suitable experimental techniques. Here, I will describe the application of two experimental techniques to this endeavor, i.e. extreme-ultraviolet time-resolved photoelectron spectroscopy (XUV-TRPES) [1] and water-window attosecond transient-absorption spectroscopy (WWATAS) [2,3]. TRPES has been applied to follow the ultrafast photoisomerization dynamics of stilbene in the gas and liqiud phases, revealing the nature of the involved conical intersections, intermediate states and vibrational coherences in both phases of matter [4]. The dominant influence of the liquid phase has been attributed to frictional forces that slow down the time scales by a factor of ~2. WWATAS has been applied to resolve femtosecond proton transfer in ionized urea solutions, revealing that the dominant pathway consists in proton transfer from an ionized urea molecule to a neutral one [5]. The intensity and the photon energy of the corresponding X-ray transition have been found to be mainly sensitive to the electronic-structure relaxation and the proton transfer, respectively, suggesting the ability of WWATAS to distinguish electronic from structural dynamics. Finally, the application of WWATAS to electronic relaxation of pyrazine in the gas and liquid phases will also be discussed. Whereas oscillatory population dynamics between excited states have been observed in the gas phase for the first time, these oscillations are absent in the liquid phase, indicating a dramatic effect of solvation on the electronic relaxation process. These methods reveal the potential of ultrafast spectroscopy based on high-harmonic-generation sources to understand the influence of solvation on the fastest electronic and nuclear dynamics underlying chemical dynamics. |
Wednesday, June 7, 2023 12:00PM - 12:30PM |
K03.00004: Visualizing excited state structural and electronic dynamics Invited Speaker: Roseanne J Sension The fate of a photoactive molecule is determined by the electronic and structural rearrangements that follow excitation. Femtosecond (fs) X-ray free electron lasers (XFELs) have made it possible to use X-ray absorption spectroscopy and X-ray emission spectroscopy to probe changes in electronic configuration and atomic structure as a function of time, beginning from the initial excited state. Both ‘movies’ of coherent or ballistic motion and ‘snaphots’ of local minima or kinetic intermediates are possible. Polarization anisotropy, long exploited in ultrafast optical measurements, permits decomposition of the X-ray transient difference signal into contributions along the direction parallel to the transition dipole initially pumped, and perpendicular to this transition dipole. This decomposition allows the analysis of asymmetric sequential structural changes of photoexcited molecules in isotropic solution. We have used femtosecond X-ray absorption near edge structure (XANES) at the Co K-edge to characterize the excited state dynamics of cobalamins, B12 coenzymes and analogues. Femtosecond X-ray emission spectroscopy (XES) in the Kβ1,3 and valence-to-core regions provides additional insight into the electronic evolution. |
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700