Bulletin of the American Physical Society
APS March Meeting 2023
Volume 68, Number 3
Las Vegas, Nevada (March 5-10)
Virtual (March 20-22); Time Zone: Pacific Time
Session Y17: Structure and Dynamics in Chemical Physics |
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Sponsoring Units: DCP Chair: Aleksander Durumeric, Free University of Berlin Room: Room 209 |
Friday, March 10, 2023 8:00AM - 8:12AM |
Y17.00001: Synchrotron X-ray spectroscopy for the local structure analysis of heteroatoms in the zeolite Kakeru Ninomiya, Maiko Nishibori, Ryota Osuga, Ginpei Tanaka, Mizuho Yabushita, Kiyoshi Kanie, Atsushi Muramatsu Heteroatom zeolites exhibits a significant modulation of the micropore structure, surface acidity, and particle size depending on the T-site substitution position of the heteroatom, which significantly changes the physical and chemical properties. However, the technology to analyze the accurate atomic position and local structure of heteroatoms introduced into the zeolite framework with complex structures has not been established. These are a challenge for synthesizing truly structure-controlled zeolites. |
Friday, March 10, 2023 8:12AM - 8:24AM |
Y17.00002: Computational Macroscopic QED for Vibrational Polaritons in Infrared Nanocavities Athul S Sambasivan Rema, Felipe F Herrera Near-resonant molecule-field interactions have attracted significant attention in chemical physics and quantum optics [1,2]. We study the quantum dynamics of a molecular vibration coupled to near-field modes of an infrared nanoresonator using macroscopic quantum electrodynamics (QED). Nanophotonic structures vary in geometry and material properties, which makes the calculations of interaction dynamics challenging [3]. We use the electromagnetic Green’s tensor of the nanophotonic structure to construct frequency and position dependent interaction Hamiltonians in macroscopic QED that are used to derive and numerically solve the system of non-Markovian integro-differential equations (IDE) that describe the dynamics of vibrational and photonic degrees of freedom in strong coupling. The material and dipole parameters are encoded in the structure of the kernel function of the IDE. We solve for photonic and vibrational observables for a single non-polar anharmonic vibration in a resonant infrared nanocavity and compare the results with recent phenomenological Markovian models developed for vibrational polaritons [4], to better understand the reach and limitations of reduced Markovian quantum optics models to describe currently available experiments. |
Friday, March 10, 2023 8:24AM - 8:36AM |
Y17.00003: Water decomposition equilibrium under vibrational strong and ultrastrong coupling Kaihong Sun, Raphael F Ribeiro Pioneering experimental results have shown chemical equilibrium can be shifted significantly inside an optical cavity. The formation of hybrid states of light and matter (polaritons) and weakly coupled modes (dark states) has been argued to be the main contributor to the observed changes, but the mechanistic understanding is lacking. In this presentation, we will describe the main findings of our recent studies of (single-mode) microcavity effects on chemical equilibrium. We theoretically investigated the waterdecomposition reaction under strong and ultrastrong coupling conditions and found that the equilibrium constant can be enhanced or suppressed under distinct scenarios. Connections to recent experiments and future challenges will be highlighted. |
Friday, March 10, 2023 8:36AM - 8:48AM |
Y17.00004: Mesoscopic characterization of vibrational polariton transport phenomena Enes Suyabatmaz, Raphael F Ribeiro Recent experimental works have shown strong light-matter coupling can significantly alter chemical and physical kinetics in an infrared (IR) microcavity. In the regime of collective strong interactions between confined IR modes and molecular vibrations, hybrid light-matter states denoted vibrational polaritons emerge. The delocalization of polaritons is a fundamental feature enabling control of energy transfer and other physicochemical properties with microcavities. While prior studies have analyzed disorder-induced loss of coherence in organic microcavities which are typically strongly disordered, much less is known about the effects of structural and energetic disorders on vibrational strong coupling. In this work, we employ techniques of mesoscopic physics to provide a quantitative analysis of real-space delocalization in vibrational polaritons and weakly coupled vibrational modes in an IR Fabry-Perot cavity and demonstrate how the real-space properties of polaritonic states can be controlled by detuning, quality factor, and light-matter interaction strength. We will also provide a comparison of organic and IR microcavity polaritons and conclude by highlighting the connections between theoretically obtained trends and recent observations of polariton-assisted chemistry. |
Friday, March 10, 2023 8:48AM - 9:00AM |
Y17.00005: Relativistic real-time time dependent density functional theory for valence and core level attosecond transient absorption spectroscopy Torsha Moitra, Lukas Konecny, Marius Kadek, Angel Rubio, Michal Repisky We present fundamental insights on pure electron dynamics captured by pump–probe attosecond transient absorption processes, within the realms of relativistic real–time time-dependent density functional theory [1-3], where both scalar and spin-orbit relativistic effects are included variationally using modern atomic mean-field eXact two-component (amfX2C) Hamiltonian [4]. We address how this technique records the signature of the transient dynamics triggered by the pump pulse imprinted onto the molecular response to probe pulse, including effects of additional degrees of freedom (pump pulse features and pump–probe time delay) absent in conventional spectroscopy. Non-equilibrium response theory will be used to lend further interpretation of the simulated spectral features. Furthermore, the necessity to incorporate relativistic corrections for simulating L-edge x-ray absorption processes are showcased by comparing spectra obtained with non-relativistic, amfX2C and Dirac-Coulomb Hamiltonian. |
Friday, March 10, 2023 9:00AM - 9:12AM |
Y17.00006: Understanding High Fluorescence Quantum Yield and Simultaneous Large Stokes Shift in Push-Pull Molecular Dyads in Polar Solvent Raka Ahmed, Arun K Manna Donor-acceptor (D-A) systems are potential candidates for bioimaging, sensing, photonic and photovoltaic applications. Recently, large Stokes shift (SS) with remarkably high fluorescence quantum yield (ΦF) in polar solvents were reported for a pyrene and styrene-based D-A chromophore (pentafluorostyryl-aminopyrene, StyPy) and also for diphenylphenanthroimidazole (PPI) and triazolopyridine (TP) based D-π-A dyads with varied phenyl π-bridge length (PPI-Pn-TP, n =1, 2). Solvent driven stabilization of twisted intramolecular charge-transfer (TICT) emissive-state for the StyPy and of ICT for PPI-Pn-TP dyads were claimed to be responsible for the observed large SS. However, TICT/ICT generally corresponds to decoupling of frontier molecular orbitals (FMOs) between the D and A units, which is expected to reduce ΦF. |
Friday, March 10, 2023 9:12AM - 9:24AM |
Y17.00007: N-Heterocyclic Carbene-based Low-Dimensional Metal-Organic Frameworks with Metal-Dependent Electronic Properties Boyu Qie, Ziyi Wang, Jiaming Lu, Peter H Jacobse, Michael F Crommie, Felix R Fischer The electronic structure of metal-organic frameworks (MOFs) is intimately linked to the selection of metals, organic ligands, and binding modes. The highly tunable lattice parameters in MOFs can give rise to non-trivial topological and quantum behaviors. Despite this, there is a paucity of experimental demonstrations of MOFs with unconventional binding modes, such as carbenes. Moreover, the electronic structures of carbene-based MOFs, relying on the unique metal-carbene d→π* back-donation bonding, have rarely been studied. |
Friday, March 10, 2023 9:24AM - 9:36AM |
Y17.00008: Isotope effects in the electronic spectra of ammonia using ab initio semiclassical dynamics Eriks Kletnieks, Yannick C Alonso, Jiri Vanicek The experimentally observed isotope effects in the absorption spectra of ammonia are reproduced theoretically using the semiclassical thawed Gaussian approximation. As a single trajectory method, it can benefit from the on-the-fly ab initio implementation, in which the potential is evaluated locally. Whereas the standard global harmonic approximation fails due to the high anharmonicity of the first excited electronic state of ammonia, the experimental spectra of ammonia isotopologues (NH3, NDH2, ND2H, ND3) are very well reproduced by the semiclassical on-the-fly calculations. Moreover, the isotope effects – narrowing of transition band, shift in 0-0 transition, and decreasing of the peak spacing – are all captured by this semiclassical method. The activation of different normal modes upon excitation in the case of each isotopologue is further discussed in detail. |
Friday, March 10, 2023 9:36AM - 9:48AM |
Y17.00009: Role of Dispersion in the Molecular Geometries of Mn(III) Complexes SABYASACHI ROY CHOWDHURY, Ngan Nguyen, Bess Vlaisavljevich Transition metal complexes are well known for their applications in diverse research areas such as molecular magnetism, molecular electronics, and catalysis. Theoretical modelling of such phenomena requires accurate determination of electronic structure and that cannot be achieved without reliable molecular geometries. Here we investigate the molecular geometries of manganese(III) complexes. For the high-spin state’s geometry, the density functionals significantly overestimate the Mn-Namine bond distances, although the geometry for the intermediate-spin state is well-described. Comparisons with several wavefunction-based methods demonstrates that this error is due to the limited ability of density functional theory (DFT) to recover dispersion beyond a certain extent. Among the methods employed for geometry optimization, Møller-Plesset perturbation theory (MP2) appropriately describes the high-spin geometry, but results in an elongated Mn-O distance in the intermediate spin-state. On the other hand, complete active space second-order perturbation theory (CASPT2) results in a good description of the geometry for the intermediate spin state, but also sufficiently recovers dispersion performing well for the high-spin state. Despite the fact that the electronic structure of both spin states is dominated by one electron configuration, CASPT2 offers a balanced approach leading to molecular geometries with much better accuracy than MP2 and DFT. A scan along the Mn-Namine bond demonstrates that coupled cluster methods (i.e., DLPNO-CCSD(T)) also yield bond distances in agreement with experiment, while multiconfiguration pair density functional theory (MC-PDFT) is unable to recover dispersion well enough, analogous to single reference DFT. |
Friday, March 10, 2023 9:48AM - 10:00AM |
Y17.00010: Physical and Chemical Modifications of Nanomaterial-Chiral Molecule Interface for Enhanced Chirality-Transfer Aaron Forde, Amanda J Neukirch, Sergei Tretiak, Amanda C Evans Nanostructured semiconductors have already shown to provide superior optical properties, such as tunable wavelength and high intensity of absorption or emission of light, for opto-electronic devices compared to their bulk counterpart. An emerging area of research is to also control the circular polarization of absorption and emission states. Typically achiral organic molecules are used as passivation ligands for colloidal nanomaterials. Semiconductor nanomaterials interfaced with achiral molecules show no tuneability of the polarization state of absorbed or emitted photons, in the absence of external fields. But, experimentally it has been observed that interaction of semiconductor nanomaterials with chiral molecules induces polarized optical signatures (chiroptical activity). Specifically, chiral enantiomers (ie handedness) interfaced with the semiconductor nanomaterial can provide equal and opposite polarized optical signals originating from the nanomaterial (i.e. chirality transfer). This provides opportunities to develop photo-detectors which are sensitive to the polarization state of incoming photons along with novel photo-diode device architectures for processing optical signals. In the context of semiconductor-organic molecular interface, we want to understand what material and molecular properties are most important for enhancing the intensity of polarized optical signatures induced by chirality transfer. Here we explore chirality-transfer in lead-halide perovskite and lead chalcogenide quantum dots with chiral carboxylic and ammonium molecules bound to their surface. Material properties, such as effective mass, and chemical properties, such as molecular polarity, which enhance intensity of chiroptical signatures will be discussed. |
Friday, March 10, 2023 10:00AM - 10:12AM |
Y17.00011: Multiphase modelling of the reduction of quartz in a silicon carbide reactor Brady Metherall Traditional refining of silicon generates carbon dioxide emissions that are released into the atmosphere. An alternative process under experimental exploration uses a lower temperature, which leads to different chemical reactions dominating. The goal of this alternate process is to reduce the greenhouse gas emissions, and produce silicon carbide, which can then be efficiently processed into silicon. We develop a macro-scale multiphase model for chemical and transfer processes within the reactor. We derive governing equations for the concentration of silicon monoxide, carbon monoxide, and carbon dioxide, and conservation equations for quartz, carbon, and silicon carbide. We solve the leading-order system numerically, and show examples of the conversion of carbon to silicon carbide. |
Friday, March 10, 2023 10:12AM - 10:24AM |
Y17.00012: The effect of methylation on the excited state dynamics of 2-thiouracil Susanne Ullrich, Yingqi Qu, Sarita Shresta, Abed Mohamadzade Thiouracils, where an oxygen atom in uracil is replaced by sulfur, have been observed to undergo fast and efficient intersystem crossing (ISC) from the lowest singlet excited state, S1(np*), to the triplet manifold along a sulfur-out-of-plane (op-S) coordinate. Our recent time-resolved photoelectron spectroscopy (TRPES) studies on a series of thiouracils have shown that minor changes such as the position and degree of thionation profoundly alter the subsequent dynamics on the lowest triplet state, T1. These differences are attributed to intricate details of the potential energy topography, specifically the presence and relative energies of two minima with boat-like (T1 boat) and sulfur-out-of-plane (T1 op-S) geometries. In the case of 2-thiouracil, the excited state population equilibrates between both minima. ISC back to the ground state (GS) depends on spin-orbit couplings (SOC) and accessibility of the T1/GS crossing points at boat-like and op-S geometries with T1 op-S/GS clearly favored. |
Friday, March 10, 2023 10:24AM - 10:36AM |
Y17.00013: Exploring the role of chemical reactions in the selectivity of tyrosine kinase inhibitors Mojgan Asadi, Wenjun Xie, Arieh Warshel A variety of diseases are associated with tyrosine kinase enzymes that activate many proteins via signal transduction cascades. The similar ATP-binding pockets of these tyrosine kinases make it extremely difficult to design selective covalent inhibitors. The present study explores the contribution of the chemical reaction steps to the selectivity of the commercialized inhibitor acalabrutinib over Bruton’s tyrosine kinase (BTK) and the interleukin-2- inducible T-cell kinase (ITK). Ab initio and empirical valence bond (EVB) |
Friday, March 10, 2023 10:36AM - 10:48AM Author not Attending |
Y17.00014: Sensing Chiral-Induced Spin Selectivity in Photogenerated Radical-Pairs with NV Centers via Lee-Goldburg Decoupling Laura Alicia A Völker, Konstantin Herb, Christian L Degen, John M Abendroth Chiral-induced spin selectivity (CISS) refers to spin-dependent interactions between electrons and inversion asymmetric materials.1 Recently, it has been hypothesized that the CISS effect could spin-polarize electrons during charge transfer in photoexcited donor-chiral bridge-acceptor (D-B-A) molecules which would have severe implications in biology as well as for quantum information science using spin qubit pairs.2,3 However, whether charge transfer through the chiral bridge actually results in a spin-polarized state has not been resolved to date.4 |
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