Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session F58: DFT and Beyond IVFocus

Hide Abstracts 
Sponsoring Units: DCP DCOMP DPOLY DCMP Chair: Marivi Fernandez Serra, State Univ of NY  Stony Brook Room: Mile High Ballroom 3B 
Tuesday, March 3, 2020 8:00AM  8:36AM 
F58.00001: LongRange Correlations in Density Functional Theory Invited Speaker: Tim Gould Accurate and lowcost reproduction of electron correlations remains one of the most difficult problems in chemical physics. Enormous progess has been made on dealing with shortrange correlations. But longrange correlations remain challenging, despite contributing to a range of important quantum chemical problems including dispersion forces [12], strong correlations [34] and charge transfer excitations [5]. This talk will discuss the origins of key types of longrange correlations in density functional theory, and consider physical, chemical and mathematical perspectives on the problem. It will discuss some lowcost solutions to difficult problems in the field, introduced by the author and others, and will highlight some of the challenges that lie ahead. It will stress the importance of the universal functional in devising new approximations, and how quantum state ensembles can help, even in "mundane" cases. 
Tuesday, March 3, 2020 8:36AM  8:48AM 
F58.00002: Embedding tools to improve density functionals. Adam Wasserman As is well known, standard approximations to the exchangecorrelation (XC) functional often do not yield accurate energies and/or spindensities when chemical bonds are stretched. We use density embedding theory to examine the behavior of the nonadditive contribution to the XC energy and to propose physicallymotivated approximations for this contribution as atoms dissociate. We also discuss a recent approach to develop improved approximations for the nonadditive noninteracting kinetic energy, and why this is a challenging problem. 
Tuesday, March 3, 2020 8:48AM  9:00AM 
F58.00003: KohnSham accuracy at a fraction of the cost: Nonlocal subsystem DFT and orbitalfree DFT Michele Pavanello Subsystem DFT enables first principles simulations to approach realistic time and lengthscales, and most importantly sheds light on the dynamical behavior of complex systems. The accuracy of subsystem DFT is dependent on the quality of the employed nonadditive Kinetic Energy Density Functionals (KEDF). As these are customarily of semilocal character (i.e., they depend locally on the value of the density and its gradient), so far subsystem DFT has only been able to approach weakly interacting subsystems. In this presentation, we employ latestgeneration nonlocal KEDF^{1,2} in subsystem DFT^{3} and orbitalfree DFT^{4} simulations. Our results are of KSDFT accuracy while still keeping the computational cost at a fraction of typical KSDFT algorithms. The developed KEDFs are accurate enough also in the context of orbitalfree DFT where we show they are able to approach millionatom semiconductor systems arranged in complex structures featuring Schottky barriers and spacecharge regions. 
Tuesday, March 3, 2020 9:00AM  9:12AM 
F58.00004: Absolutely Localized Multireference DFT Embedding Daniel Graham, Xuelan Wen, Dhabih Chulhai, Jason Goodpaster While density functional theory (DFT) has been a workhorse for quantum mechanical chemical calculations, current implementations have several deficiencies. Systems which require a multireference description are often poorly described by current DFT methods. Quantum embedding methods provide a strategy for performing localized highly accurate calculations on chemical systems while not incurring high cost computational scaling. Dividing a system into absolutely localized subsystems  described by only the basis functions of the subsystem atoms  can significantly reduce computational cost. The Huzinaga projection operator based absolute localization wavefunction embedded in DFT (WFinDFT) embedding methods match full system WF energy differences across a diverse test set including multireference WF calculations embedded in DFT. We have also studied large metal organic framework (MOF) cluster models, specifically gas adsorption on an FeMOF74 cluster model and can achieve within 0.22 kcal/mol of the full system CASPT2 energy at a fraction of the computational cost. The absolute localization WFinDFT method allows for highly accurate calculations on multireference systems beyond the scope of current techniques. 
Tuesday, March 3, 2020 9:12AM  9:24AM 
F58.00005: Towards an orbitalfree kinetic energy density functional for molecular systems Omololu AkinOjo A new kinetic energy density functional (KEDF) for systems composed of many atoms (molecular systems) is proposed. This KEDF contains the full vonWeizsacker KEDF as well as correction terms ("Pauli KEDF") appropriate for describing fermionic systems. Two of these correction terms are investigated: one from approximations based on the kinetic energy of fermions in an infinite well potential and the other from suitable averages of the kinetic energies of atoms. The peformance of these new KEDFs will be presented as well as possible routes for further development. 
Tuesday, March 3, 2020 9:24AM  9:36AM 
F58.00006: Analytic inversion procedure for the exact nonadditive kinetic potential functional V^{nad} Mojdeh Banafsheh, Leeor Kronik, Tim Gould, David Strubbe, Tomasz A. Wesolowski The nonadditive kinetic potential functional V^{nad }is a key issue in densitydependent embedding methods, such as Frozen Density Embedding Theory and PartitionDFT. V^{nad} is a bifunctional of pairs of specific electron densities ρ_{A }and ρ_{B}. We report here an inversion procedure to generate reference V^{nad }for weakly overlapping ρ_{A }and ρ_{B}. To obtain the exact V^{nad }we used an analytical inversion procedure that we proposed (M. Banafsheh, T.A. Wesolowski, Int. J. Quant. Chem. 118 (2018): e25410). We discuss the constraints on the choice of electron densities to assure their admissibility. Mathematical challenges of satisfying these constraints will be presented in detail. The potential at small overlap is constructed for various diatomic systems of four electrons at different interatomic distances. These results are compared with the potential obtained using common kinetic functional approximations. V^{nad } is also presented for some diatomic systems including more than 4 electrons in which two electrons are localized with high precision in space and the accuracy of V^{nad} is assured. We are now studying the forward KohnSham problem for some small diatomic systems using the analytically inverted potential and comparing with the standard KohnSham approach. 
Tuesday, March 3, 2020 9:36AM  9:48AM 
F58.00007: Bond energies of molecules using optimal transport theory for the strictlycorrelatedelectron (SCE) limit of DensityFunctionalTheory Kshiteej Deshmukh, Kaushik Dayal Standard KohnSham DFT starts from a meanfield approximation: the kinetic energy is modeled exactly, while the electronelectron interactions are modeled through a split into a meanfield term, and corrections from the exchangecorrelation term. The SCE limit starts from the opposite limit: the electronelectron interactions are assumed to dominate over the kinetic energy, and hence it is a semiclassical limit. It is hence well suited to study stronglycorrelated situations, e.g. bond breaking. While the SCE limit includes manybody interactions, it can be identified as a problem from Optimal Transport theory with Coulomb cost function. Hence it can be solved by a nested optimization in its dual (Kantorovich) formulation. We incorporate the Kantorovich solution within the KSDFT framework and solve it using the finite element method. Bondenergy curve is obtained using this method for hydrogen molecule, and is compared against other exchangecorrelation models to show the improved results. We then investigate bondbreaking in ethane and other small molecules using the SCE limit. 
Tuesday, March 3, 2020 9:48AM  10:00AM 
F58.00008: How accurate can a metaGGA+vdW functional be simultaneously for chemisorption and physisorption of molecular adsorption on transition metal surfaces? Manish Kothakonda, Ruiqi Zhang, Jinliang Ning, James Furness, Jianwei Sun Understanding molecular adsorption on transition metal surfaces underpins many problems in heterogeneous catalysis. Accurately predicting the adsorption energies has been a challenging task as simultaneously capturing chemical and van der Waals (vdW) bonds in a single functional is difficult. In this work, we combine the semilocal metaGGA made simple (MGGA_MS) functional with the rvv10 vdW correction [13]. We reparametrize the functional by fitting to the atomization energies of covalently bonded molecules and the Ar2 binding curve. The resulting MGGA_MS + rVV10 is validated against a set of 38 systems including chemisorption and physisorption features with experimental [4] adsorption data. 
Tuesday, March 3, 2020 10:00AM  10:12AM 
F58.00009: Asymptotic behavior of the exchangecorrelation energy density and the KohnSham potential in density functional theory: exact results and strategy for approximations Eli Kraisler Density functional theory (DFT) is nowadays the leading theoretical framework for quantum description of materials from first principles. The predictive power of DFT critically depends on an accurate approximation to the generally unknown exchangecorrelation (xc) energy functional. Approximations to the xc functional can be constructed from first principles by satisfying known properties of the exact functional. In this talk I focus on two such exact properties: the asymptotic behavior of the xc energy density per particle, e_{xc}[n](r), and the asymptotic behavior of the KohnSham potential, v_{xc}[n](r), in finite manyelectron systems. It is shown that these two properties are independent: fulfillment of one does not guarantee the other. In this process, a new quantity, the xc hole response function, is defined, some of its properties are deduced and its exact exchange part is analytically derived. A strategy for development of advanced approximations for exchange and correlation with a correct asymptotic behavior is suggested [1]. 
Tuesday, March 3, 2020 10:12AM  10:24AM 
F58.00010: Methods of corrections to to GEA approximations of the Pauli potential Jeremy Redd, Antonio Cancio In recent years many advances have been made in OrbitalFree Density Functional Theory (OFDFT), which attempts to remove orbitals from the KohnSham DFT approach, either completely, or by approximating the kinetic energy density from metaGGA exchange correlation functionals. The difficulty in OFKE models is in modeling the Pauli energy, the contribution to the KE of Pauli statistics. One aspect of this problem is correctly producing the OF Pauli potential, the functional derivative of the Pauli KE. Recent mathematical analysis of orbital free kinetic energy models based on Gradient Expansion Approximations (GEA)s, like the Airy gas model, have offered insight in modeling the Pauli potential for neutral atoms. However all of these models suffer from gross inaccuracies in the nuclear cusp region, as well as an unexpected deviation in the core. The exact Pauli potential approaches a constant near the nucleus related eigenvalue of the lowest occupied atomic orbital, but all GEAs become infinitely negative at the singularity. We propose a smooth nonanalytic stitching function to correct the error in the near nuclear region for Pauli potential GEAs, and explore the outer core. This is similar to work done by Perdew and Constantin as well as previous work from this group done on KEDs. 
Tuesday, March 3, 2020 10:24AM  10:36AM 
F58.00011: Practical Density Functional Theory Beyond the ZeroSum Limit: M11plus Pragya Verma, Benjamin Janesko, Ying Wang, Xiao He, Giovanni Scalmani, Michael J. Frisch, Donald G Truhlar Conventional approximate DFT functionals are based on what exchange would be a nearly homogeneous electron gas. This model effectively uses likespin exchange to model oppositespin correlation, producing a "zerosum" tradeoff in performance for some classes of problems, including bond energies vs. barrier heights or valence vs. Rydberg excitations. We argue that including new ingredients in a functional can provide beyondzerosum broad accuracy. We demonstrate this by adding a new ingredient to the flexible M11 longrangecorrected hybrid meta functional form. The new ingredient is an inexpensive rung3.5 bound to the exact exchange energy density. The M11 form was reoptimized with these terms, producing a functional called M11plus. Tests for thermochemistry, kinetics, and response properties suggest M11plus is one of the most broadly accurate occupiedorbitalonly DFT functionals available to date. 
Tuesday, March 3, 2020 10:36AM  10:48AM 
F58.00012: Numerical analysis of thermodynamic limit extrapolation powerlaws in the uniform electron gas using connectivitytwistaveraged coupled cluster doubles theory Tina Mihm, Bingdi Yang, Laura Weiler, Alexandra McIsaac, Andreas Grueneis, Sai Ramadugu, James Shepherd We recently developed a coupledcluster theory method in the uniform electron gas (UEG) for improving twist averaging in solids [1]. The method finds a special twist angle that gives comparable results to conventional twist averaging at a reduced cost. Here, we apply this new method to calculate the thermodynamic limit energies of the uniform electron gas across a range of densities. The highdensity limit is then used to derive general power laws for extrapolation. Time permitting, we will also show preliminary results for real systems using the Vienna abinitio software package [2][3]. 
Follow Us 
Engage
Become an APS Member 
My APS
Renew Membership 
Information for 
About APSThe American Physical Society (APS) is a nonprofit membership organization working to advance the knowledge of physics. 
© 2023 American Physical Society
 All rights reserved  Terms of Use
 Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 207403844
(301) 2093200
Editorial Office
1 Research Road, Ridge, NY 119612701
(631) 5914000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 200452001
(202) 6628700