Past Meetings

APS March Meeting

2020 DCP-Sponsored Focus Sessions

05.01.01 Electronic-vibrational Coupling in Light Harvesting


(Same as 16.01.22, 01.01.44, 06.01.09)

Energy harvesting processes in organic and hybrid perovskite photovoltaics and in natural and artificial photosynthetic systems often rely on interplay between electronic and vibrational excitations. These processes are fast, generally requiring ultrafast spectroscopic probes to disentangle. Though many applications rely essentially on the electronic energy, effects of electron-vibration coupling including polaron formation and non-adiabatic effects can be essential to the electronic properties. This Focus Symposium will highlight experimental and theoretical progress in understanding optical absorption and energy transfer processes in polymers, aggregates, single molecules, quantum dots, and hybrid perovskites, including study of singlet fission, with a focus on the electron-vibration coupling.

05.01.02 Ultrafast Spectroscopies and Coherent Phenomena in the X-ray Domain


(Same as 24.01.02, 06.01.10)

Probing ultrafast dynamics in molecules requires both sufficiently high temporal resolution as well as observables sensitive to the evolution of the relevant degrees of freedom; generally the nuclear and electronic character in photochemical processes. To capture the vibrational and electronic motions on their inherent timescales will require femto- and attosecond time resolution. As for the choice of observable, recent advances in both the experimental generation of tunable ultrashort X-ray pulses, as well as the computational/theoretical simulation of spectroscopic X-ray properties, has resulted in a surge of interest in the utilization time-resolved X-ray spectroscopies to both prepare and probe molecular wave packets. Of particular interest is the ability of core-spectroscopies to interrogate the time-evolving vibronic character and electronic coherences in complex molecules, be it in the form of nonadiabatic dynamics between electronic states driven by nuclear motion, or the attosecond evolution of electronic wave packets generated by broadband excitation. This symposium will bring together experimental and theoretical researchers to present recent results and evaluate the future potential of X-ray spectroscopies to image the coherent evolution of wave packet dynamics, using linear and non-linear spectroscopies in both the femto- and attosecond time regimes.

05.01.03 Coherent Nonlinear Optical Microscopy


(Same as 04.01.31, 03.01.31, 02.01.57, 01.01.45, 24.01.03)

Coherent nonlinear optical microscopies provide spatially-resolved access to chemical and dynamic information, typically with minimal or no labeling, so are well-suited to address increasingly demanding characterization needs in areas ranging from materials science to biophysics. Accordingly, these techniques continue to enjoy active development and deployment. This symposium will bring together experts in the field to discuss how new techniques, theoretical models, and application areas are advancing the field and opening up new opportunities.

05.01.04 Water Dynamics in Different Environments: Experiment and Theory


(Same as 16.01.23, 04.01.32, 03.01.30, 02.01.55)

The importance of water across many disciplines of science and engineering cannot be overstated. Water shapes our blue planet, is a unique solvent in chemistry, the ‘elixir of life’ in biology, a key corrosion agent in engineering, and a complex fluid with a multitude of anomalies in its phase behavior in physics. Despite its importance, a full understanding of water dynamics across its phase diagram, its interaction with interfaces, and changes under confinement has remained challenging. In this symposium, we will discuss advanced experimental and theoretical aimed at unraveling the dynamical signatures of this fascinating liquid in different phases and environments.

Organizers: Mischa Bonn (MPI Mainz, Germany), Teresa Head-Gordon (UC Berkeley, USA)

05.01.05 Density Functional Theory and Beyond


(Same as 16.01.21, 01.01.46)

Density Functional Theory (DFT), in both its ground-state and time-dependent (TD) flavors, is an exact reformulation of the quantum mechanics of many-body systems. Used in more than 40,000 papers annually, DFT provides a useful balance of accuracy and efficiency for electronic structure and response calculations in molecules, clusters, and solids. DFT is the only computationally feasible quantum mechanical approach to some of the most interesting and topical problems in chemical physics today, including catalysis, new Li battery materials, stacking interactions in DNA, phase transitions, the design of solar cells, electronic transport, laser-control of molecules and solids, ultrafast laser-induced demagnetization, time-resolved spectroscopies, and photodynamics generally. There are however many problems for which the currently used functional approximations and formulations of DFT need improvement; these applications include strongly correlated and multireference systems, transition metal chemistry, dynamics far from equilibrium, and globally accurate potential energy surfaces, and there is significant on-going progress to address these challenges. The effort to find universal methods that work well in all the areas of interest, as required for the most complex applications, also continues. At the same time, there have been significant developments in alternative methods, based on for example, many-body perturbation theory and non-equilibrium Green’s functions. This symposium highlights some of the recent advances in both theory development and applications. Note that there will also be a Pre-Meeting tutorial on DFT and TDDFT for those interested in learning about the fundamental elements in these theories. The symposium welcomes contributed talks to complement the invited talks and to broaden the scope.

Organizers: Kieron Burke (U.C. Irvine), Neepa Maitra (Rutgers University at Newark)

05.01.06 The Chemical Physics of Molecular Polaritons


(Same as 01.01.47)

Molecular ensembles embedded in confined electromagnetic environments can undergo strong coupling between their collective molecular excitations and photonic modes, giving rise to hybrid light-matter states known as polaritons. Molecular polaritons have been shown to be ideal playgrounds to control thermally-activated and photoinduced processes, modify optoelectronic properties, design new spectroscopies, or even recreate exotic states of matter at room-temperature. This symposium gathers experts in theory and experiment to provide an outlook of recent chemical physics developments in the fastly growing field of molecular polaritonics.

Organizers: Joel Yuen-Zhou and Wei Xiong (UCSD)