Bulletin of the American Physical Society
48th Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 62, Number 8
Monday–Friday, June 5–9, 2017; Sacramento, California
Session M4: Energy and Time Domain Spectroscopy of Fullerenes and EndofullerenesInvited
|
Hide Abstracts |
Chair: Steven Manson, Georgia State University Room: 309 |
Thursday, June 8, 2017 8:00AM - 8:30AM |
M4.00001: Migratory resonances and Wigner timers in the photoionization of fullerene class of molecules Invited Speaker: Himadri Chakraborty Empty fullerenes and atom-encaging endofullerenes are quintessential symmetric molecules exhibiting near stability in the room temperature. This property endows them with the quality to be tested for spectroscopic information otherwise inaccessible with regular atoms and molecules. Probing the response of fullerenes and endofullerenes to electromagnetic radiations is one classic way to accomplish this. Conventional spectroscopy of determining the photoelectron count and kinetic energy, as the frequency of the incoming photons varies, predicts varieties of resonances for such molecules. These resonances fundamentally originate from either the correlated electronic motions leading to plasmons [1,2] or from the molecule's structural symmetry inducing diffractions [3] or even from the mixing of both these effects in tandem [4]. A particularly exotic class of these resonances, which will be emphasized in the talk, includes photoexcitation at one site of the molecule but its subsequent decay at a different location [5], as well as a coherent admixture of this mechanism with localized Auger processes [5,6]. The other part of the talk will be devoted to connect to a more contemporary form of spectroscopy by evaluating the time-of-flight of the photoelectron, starting from its production at the molecule to the detector. This utilizes a Wigner clock based on the knowledge of energy-dependent photoelectron quantum phase. It will be shown that the information that can be obtained from the knowledge of this time is often consistent with the underlying electron correlative dynamics, both at the energy region of the giant plasmon resonance [7] and at the generic Cooper-type minima (or anti-resonances) [8,9]. A selection of the results will be presented which are computed by the density functional approximation. The ground state of the molecule is described in a local density approximation (LDA) framework with accurate exchange correlation potential [1]. And a linear-response variant of LDA (TDLDA) is utilized to describe the interaction with the photon [1,10]. Future research questions will be posed. Besides two postdocs, a PhD student, and the external collaborators, the program involved a large number of undergraduate students. [1] Madjet et al, \textit{J. Phys. B} \textbf{41}, 105101 (2008); [2] Madjet et al, \textit{Phys. Rev. Lett.} \textbf{99}, 243003 (2007); [3] Potter et al, \textit{Phys. Rev. A} \textbf{82}, 033201 (2010); [4] Maser et al, \textit{Phys. Rev. A} \textbf{86}, 053201 (2012); [5] De et al, \textit{J. Phys. B Letter} \textbf{49}, 11LT01 (2016); [6] Javani et al, \textit{Phys. Rev. A} \textbf{89}, 063420 (2014); [7] Barillot et al, \textit{Phys. Rev. A} \textbf{91}, 033413 (2015); [8] Dixit et al, \textit{Phys. Rev. Lett.} \textbf{111}, 203003 (2013); [9] Magrakvelidze et al, \textit{Phys. Rev. A} \textbf{91}, 053407 (2015); [10] Choi et al, \textit{Phys. Rev. A} (2017) (accepted) arXiv:1610.00346\textbf{~}[physics.atm-clus] [Preview Abstract] |
Thursday, June 8, 2017 8:30AM - 9:00AM |
M4.00002: Multiscale dynamics in fullerenes, from attosecond to microsecond timescale. Invited Speaker: Franck Lepine Fullerenes are benchmark molecules for the study of ultrafast mechanisms as they provide a broad range of processes dealing with dynamics from attosecond to long (microsecond) timescale. Modern light sources (such as intracavity FEL or HHG sources) provide new means to observe processes on various timescales and for broad excitation range. In this presentation we will discuss results on XUV induced processes where variation of photoemission delay on attosecond timescale, non-adiabatic dynamics and correlation effects are playing a role. This offers the opportunity to understand photo-induced processes on a broad multiple timescale perspectives. [Preview Abstract] |
Thursday, June 8, 2017 9:00AM - 9:30AM |
M4.00003: Electron elastic scattering off endo-fullerenes Invited Speaker: Valeriy Dolmatov The given presentation highlights the physically transparent, relatively simple, and yet reasonably complete approximation to the problem of low-energy electron elastic scattering off endohedral fullerenes $A$@C$_{N}$ along with corresponding findings unraveled on its basis. It is believed that, as of today, the highlighted results provide the most complete information about features of $e + A@{\rm C_{N}}$ elastic scattering brought about by the fullerene-cage-related, correlation-related, and polarization-related impacts of the individual and coupled members of the $A$@C$_{60}$ target on the scattering process. Each of the impacts is shown to bring spectacular features into $e + A@{\rm C_{60}}$ scattering. A remarkable inherent quality of the developed approximation is its ability to account for mutual coupling between electronic excited configurations of C$_{N}$ with those of the encapsulated atom $A$ without reference to complicated details of the electronic structure of C$_{N}$ itself. Spectacular effects in the scattering process, primarily associated with polarization of $A$@C$_{60}$ by an incident electron, are thoughtfully detailed both quantitatively and qualitatively in a physically transparent manner for ease of understanding and convenience of the audience. [Preview Abstract] |
Thursday, June 8, 2017 9:30AM - 10:00AM |
M4.00004: Photoionization of fullerene and endohedral fullerene ions at the Advanced Light Source, Lawrence Berkeley National Laboratory. Invited Speaker: David Kilcoyne Over the past 11 years, a comprehensive program on the photoionization cross-section of fullerene and endohedral fullerene molecular ions has been conducted at the ALS using the merged-beams technique pioneered during the 1960's in the UK. In contrast to targets using neutral atomic or molecular species, photoionization of ions presents unique challenges, especially large molecules such as fullerenes and in particular, rare encapsulated fullerenes, i.e., endohedrals, where an atom or molecule is trapped within the fullerene cage. I will discuss the program which initially studied C$_{\mathrm{60}}^{\mathrm{+}}$ and follow with a near-complete investigation into the photoionization of Xe@C$_{\mathrm{60}}^{\mathrm{+}}$ and C$_{\mathrm{60}}^{\mathrm{+}}$ including some remarks on the current progress on exotic endohedrals such as Sc$_{\mathrm{3}}$N@C$_{\mathrm{80}}^{\mathrm{+}}$ and Ce@C$_{\mathrm{82}}^{\mathrm{+}}$ and ending with preliminary results from the study of Au@C$_{\mathrm{60}}^{\mathrm{+}}$. Atomic ion photoionization remains a principal objective of the program which motivated a recent NSF MRI proposal to replace the recently decommissioned ALS apparatus. [Preview Abstract] |
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