Bulletin of the American Physical Society
APS March Meeting 2018
Volume 63, Number 1
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session E02: Developments of DFT from Quantum to Statistical Mechanics (III)Focus
|
Hide Abstracts |
Sponsoring Units: DCP DCOMP Chair: Michael Payne, Univ of Cambridge Room: LACC 150B |
Tuesday, March 6, 2018 8:00AM - 8:36AM |
E02.00001: Dynamical density functional theory for the collective behavior of active particles Invited Speaker: Hartmut Loewen The collective behavior of active particles represents a fascinating part of nonequilibrium many-body physics with a wealth of phenomena like swarming, activity-induced phase separation and active turbulence. In this contribution we propose an ab initio theory based on the individual active particles (or microswimmers) which is based on the dynamical density functional theory (DDFT) of classical Brownian particles. As an important and nontrivial extension, hydrodynamic interactions between the particles mediated by fluid flow are incorporated such that pushers, pullers and neutral swimmers can be discriminated in the DDFT. As an example, the theory predicts a hydrodynamic pumping state in confined active suspensions both for linear swimmers and circle swimmers which will be proposed and discussed and put into relation with recent experiments. |
Tuesday, March 6, 2018 8:36AM - 8:48AM |
E02.00002: A Density Functional Theory Study of Magnetic Fields Effects on the Intermolecular Interactions Hemanadhan Myneni, Dariusz Kedziera, Jan Andzelm, Erik Tellgren, Trygve Helgaker, Krzysztof Szalewicz Studies of strong magnetic fields (MFs) effects on the intermolecular interactions are important for the ongoing quest of designing exotic novel molecular materials. In particular, the influence of strong MFs on the physico-chemical properties of liquid water has been a very controversial subject for a long time due to low reproducibility and little consistency of the reported results. All these controversies can now be resolved using the recently developed LONDON code [1-2] that provides accurate description of properties of molecules in fields of arbitrary strength. We performed calculations using several density functionals and current-density functionals (within KS-CDFT) for water clusters in MFs of varying strength, including 40 tesla, the strongest field currently available in laboratories. All these calculations were performed using uncontracted aug-cc-pCVDZ basis-set. Performance of functionals were assessed with reference to MP2 values for smaller clusters. Further, among all the considered functionals, the one with the least RMSE is chosen to study larger clusters. |
Tuesday, March 6, 2018 8:48AM - 9:00AM |
E02.00003: Fitting a Round Peg into a Round Hole --
Constructing an Asymptotically Correct Generalized Gradient Approximation. Antonio Cancio, Kieron Burke, Guo Chen, Brandon Krull We revisit the two derivations of the PBE correlation functional: the real-space cut-off of the exchange-correlation hole and the imposition of exact conditions. These differ in the Lieb-Simon limit, exemplified by the scaling of neutral atoms to infinite N and Z. In this limit, LDA becomes relatively exact and the correction to it provides a norm for the systematic construction of GGA's. We use the leading correction for neutral atoms to design an asymptotically corrected correlation GGA as a compromise between the two constructions of PBE, one which becomes relatively more accurate for atoms with increasing atomic number. When paired with an asymptotically correct model for exchange, this acGGA satisfies more exact conditions than PBE. Combined with the known density-dependence of the gradient expansion for correlation, this correction accurately reproduces correlation energies of closed shell atoms down to Be. We test this acGGA for atoms and molecules, finding substantial improvements over PBE, but also show that optimal global hybrids of acGGA do not improve upon PBE0, and are similar to meta-GGA values. We discuss the relevance of these results to Jacob’s ladder of non-empirical density functional construction. |
Tuesday, March 6, 2018 9:00AM - 9:12AM |
E02.00004: Benchmark of computationally efficient self-interaction corrections using Fermi orbitals (FO-SIC) in DFT. Fredy Aquino, Bryan Wong We recently implemented Fermi orbital self-interaction corrections (FO-SIC) in the open source software platform NWChem. |
Tuesday, March 6, 2018 9:12AM - 9:24AM |
E02.00005: Ultra Long-Range Ab Initio Calculations Tristan Müller, Sangeeta Sharma, Eberhard K Gross, John Dewhurst We propose a generalization of the Bloch state which involves an additional sum over |
Tuesday, March 6, 2018 9:24AM - 10:00AM |
E02.00006: Joint Density-Functional Theory Invited Speaker: Tomas Arias Quantum processes in liquid environments impact broad areas from biophysics to geophysics to electrochemical physics. While density-functional theory (DFT) has enabled efficient ab initio calculations profoundly impacting the study of condensed-matter phenomena, realistic description of such phenomena in liquid environments remains a challenge. |
Tuesday, March 6, 2018 10:00AM - 10:12AM |
E02.00007: Scalability of DFT protocols for calculating quantum work in many-body systems Marcela Trujillo, Krissia Zawadzki, Roberto Serra, Irene D'Amico We report the application of DFT-inspired protocols to obtain thermodynamical quantities in many-body systems out of equilibrium. We discuss the scalability of the protocol recently proposed in Scientific Reports 7: 4655 (2017). Our study is focused on the extracted quantum work W in finite Hubbard lattices with L = 2, 4, 6, 8 sites driven by three different dynamics. We compare the exact W obtained by diagonalizing the full many body Hamiltonian with the estimate WKS calculated using the Kohn-Sham auxiliary system. In the proposed DFT protocol, we use two approximations: (i) vKSBALDA, in which we consider the Kohn-Sham potentials as in the Bethe Ansatz Local Density Approximation for the homogeneous Hubbard and (ii) vKSexact, where we use an inversion scheme to obtain the exact exchange-correlation potential. Our results show that, in both approximations, the proposed protocol is able to accurately reproduce the quantum work in the low and intermediate coupling regimes. Additionally, while vKSexact performs better in all dynamical regimes (from sudden quench to adiabatic), BALDA captures better the qualitative profile of the quantum work of the interacting system. |
Tuesday, March 6, 2018 10:12AM - 10:24AM |
E02.00008: An a priori Prediction of the Accuracy of Approximate Density Functional Theories Michelle Kelley, Tomas Arias The density functional theory (DFT) community continues to face a long-standing question: Why is DFT as accurate as it is? We present results from a new statistical approach to this question. By investigating the spatial correlations among ~107 Hartree-Fock exchange holes as a proxy to the full exchange-correlation hole, we predict the total-energy accuracy of approximate DFTs to be on the order of several percent, consistent with a posteriori observations. The presented work opens a new pathway to evaluate the accuracy of current functionals as well as aid in the development of new functionals. |
Tuesday, March 6, 2018 10:24AM - 10:36AM |
E02.00009: Modeling Phase Transition in Battery Electrodes Using the Coupled Cahn-Hilliard – Phase Field Crystal Methods Ananya Balakrishna, W. Craig Carter Phase transitions in electrode materials are typically accompanied by lattice distortions and defect formations. These microscopic configurations affect an electrochemical cycle and influence the physical properties of electrode materials. Here, we develop a 2D theoretical framework that couples a Cahn-Hilliard (CH) model describing Li-concentration evolution, with a phase-field crystal (PFC) model describing the underlying lattice symmetry of the electrode material. We apply this CH-PFC model to describe three representative examples of microstructures in a LiFePO4 electrode. First, we model lattice arrangements in a uniformly lithiated (LFP) or delithiated (FP) electrode. Next, we model a partially lithiated electrode and describe the lattice distortions across a diffuse phase boundary. Finally, we model a Cahn-Hilliard type of diffusion for the Li-concentration field and compute the accompanying structural evolution of atomic arrangements. In this numerical study, we report the formation of grains in a single FP/LFP phase, and identify the position/orientation of grain boundaries. Furthermore, the simulations track the migration of grain boundaries and demonstrate the motion of lattice defects during an electrochemical cycle. |
Tuesday, March 6, 2018 10:36AM - 10:48AM |
E02.00010: Improved Understanding of the Adsorption of Aromatic Molecules from Recent meta-GGA’s SANTOSH ADHIKARI, Bimal Neupane, Adrienn Ruzsinszky The strong rules and regulations against environmental pollution demand removal of sulphur compounds from the crude petroleum. Since thiophene is the smallest aromatic sulphur-containing compound, it is a natural choice as a test case for simulations. Previous density functional theory studies have been proven a useful tool to describe the first step toward C-S bond breaking in the hydrodesulphurization (HDS) process at metal surfaces or at different edges of MoS2 [1]. Earlier computations were done with the PW91 GGA. We are developing a better understanding of this process using two recent and improved meta-GGA’s, SCAN and SCAN+rVV10. At first we are investigating the adsorption of thiophene on transition metals, namely silver and gold, starting from the (100) surface. Our target is to find the stable site of adsorption. In parallel, we are also gaining an insight into the performance of various approximations regarding the interplay between vdW interaction and self-interaction error. |
Tuesday, March 6, 2018 10:48AM - 11:00AM |
E02.00011: One-electron energy spectra of isolated atoms via coupled-cluster singles and doubles Hirofumi Nishi, Taichi Kosugi, Yoritaka Furukawa, Yu-ichiro Matsushita The coupled-cluster theory is a wavefunction theory known as a gold standard in the field of quantum chemistry since electronic correlation effects are included with high accuracy. However, there are few reports of the one-electron energy spectra in the coupled-cluster theory. In this study, we have calculated the single-particle Green’s function within the CCSD [1] for isolated atoms from He to Ne. We have compared the results with those from the full-CI (configuration interaction). Then, we found that the CCSD successfully reproduces quasiparticle and satellite peaks stemming from many-body nature. Moreover, we clarified the physical origin of the satellites peaks. |
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