Article
Chemistry, Physical
Vishikh Athavale, Hung-Hsuan Teh, Yihan Shao, Joseph Subotnik
Summary: We derive and implement analytic gradients and derivative couplings for TDDFT-1D method, and validate its accuracy by comparing with finite difference values. Furthermore, we demonstrate its capability in locating optimized geometries and minimum-energy crossing points along conical seams.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Multidisciplinary Sciences
Simon Axelrod, Eugene Shakhnovich, Rafael Gomez-Bombarelli
Summary: The authors introduce a diabatic neural network to accelerate excited-state, non-adiabatic simulations of azobenzene derivatives and successfully predict quantum yields for unseen species that are correlated with experiment. The model provides a new approach for fast and accurate virtual screening of photoactive compounds.
NATURE COMMUNICATIONS
(2022)
Article
Physics, Multidisciplinary
T. Isdraila, V Baran, M. Colonna, A. Nicolin, M. C. Raportaru, E. Boicu
Summary: The model extends the approach for studying the collective properties of Giant Dipole Resonance, effectively considering the non-uniform density distribution inside the nucleus. The predictions show that Pygmy Dipole Resonance appears as a collective dipolar mode, closely resembling experimentally observed values of the Energy Weighted Sum Rule.
ROMANIAN JOURNAL OF PHYSICS
(2021)
Article
Computer Science, Interdisciplinary Applications
Xiao-Yu Liu, Chong Qi, Xin Guan, Zhong Liu
Summary: An efficient program for exact diagonalization of the pairing Hamiltonian in spherical systems is presented, utilizing the SU(2) quasi-spin algebra. Basis vectors with quasi-spin symmetry are generated iteratively, and the Hamiltonian matrix is diagonalized using the Lanczos algorithm. The program can calculate ground-state eigenvalues and eigenvectors of general spherical pairing Hamiltonians on standard desktop computers in a few hours, with a dimension of up to 10(8) for systems.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Ran Chen, Lasse Jensen
Summary: This work extends the Raman bond model to periodic slab systems for interpreting chemical enhancements of surface-enhanced Raman scattering (SERS) and shows that it offers a unified interpretation for localized and periodic systems. The effects of surface coverage, thickness, and roughness on the chemical enhancements have been studied, revealing that decreasing surface coverage or creating surface roughness increases the chemical enhancements. The Raman bond model is connected to the transition-based analysis of chemical enhancements and offers a unique framework for understanding SERS spectra in terms of Raman bond distributions.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Computer Science, Interdisciplinary Applications
Xiao-Yu Liu, Chong Qi
Summary: The program presented in this study can accurately solve the general pairing Hamiltonian for different mass systems. Utilizing the iterative Lanczos algorithm for matrix diagonalization, it can efficiently compute on standard desktop computers.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Mathematics, Applied
Jun Liu, Shu-Lin Wu
Summary: In this paper, a high-order numerical method for parabolic and hyperbolic PDEs is proposed, and the issue of handling the resulting large-scale dense system is addressed. Through the introduction of a parallel-in-time preconditioner, the condition number of the system is effectively reduced, leading to mesh-independent convergence rates in various numerical examples.
SIAM JOURNAL ON SCIENTIFIC COMPUTING
(2022)
Article
Engineering, Chemical
Xinggang Zhang, Dan Dai
Summary: The rhombic lattice packing model proposed here analyzes and solves the micro causes of the Janssen effect. A recurrence relation with a force transmission matrix Q is obtained, showing the transmission and accumulation of contact force along the lattice vector direction. A method for the diagonalization of Q based on tensor algebra and difference equation is proposed. The results reveal deviations from the Janssen model, except for very small top load or large force reflectivity.
Article
Mathematics, Applied
Nadiia Derevianko, Gerlind Plonka
Summary: This paper presents a new recovery procedure for extended exponential sums, utilizing classical Fourier coefficients to reconstruct the parameters and employing a stable iterative rational approximation algorithm. When a sufficiently large set of Fourier coefficients is available, the method can automatically detect the number of terms, multiplicities, and parameters of the exponential sums.
ANALYSIS AND APPLICATIONS
(2022)
Article
Physics, Condensed Matter
C. Wei, S. H. Curnoe
Summary: We completely block-diagonalize the Hamiltonian of a 16-site spin-1/2 pyrochlore cluster with nearest neighbour exchange interactions using the methods of group theory. This yields precise details about the symmetry of the eigenstates, particularly the components that are spin ice states, in order to determine the spin ice density at finite temperature. A 'perturbed' spin ice phase, where the '2-in-2-out' ice rule is largely followed, is clearly identified within the parameter space of the general model of exchange interactions, indicating the presence of a quantum spin ice phase within these boundaries.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Materials Science, Multidisciplinary
Qianrui Liu, Mohan Chen
Summary: This paper introduces the traditional finite-temperature KSDFT based on the diagonalization method and alternative methods CT, SDFT, and MDFT. The accuracy and efficiency of these methods are evaluated through testing a series of physical properties. The results show that CT, SDFT, and MDFT methods outperform the diagonalization method in terms of accuracy and advantages.
Article
Multidisciplinary Sciences
Kai-Lin Woon, Pavel A. Nikishau, Gjergji Sini
Summary: This study examines the performance of hole-hole Tamm-Dancoff approximated density functional theory (hh-TDA-DFT) on a large number of multiresonance (MR)- and donor-acceptor (D-A) thermally activated delayed fluorescence (TADF) molecules. The results show that hh-TDA combined with the B3LYP functional can accurately predict Delta E-ST values for MR-TADF molecules, while Delta E-ST is less sensitive to the nature of the functionals for D-A TADF molecules.
ADVANCED THEORY AND SIMULATIONS
(2022)
Article
Optics
Yue-Xun Huang, Ming Li, Zi-Jie Chen, Yan-Lei Zhang, Xu-Bo Zou, Guang-Can Guo, Chang-Ling Zou
Summary: Mean-field treatment (MFT) is commonly used for approximating the dynamics of quantum optics systems. However, neglecting quantum correlations between modes can lead to unexpected quantum effects. This study presents a theoretical framework based on perturbation theory and MFT to capture these effects and predicts the form and relationship of nonlinear dissipation, parasitic Hamiltonian, and nonlinear coupling rate. The framework is applied to quantum frequency conversion and shows excellent agreement with numerical simulations, revealing the neglected quantum effects by MFT and providing a more precise framework for nonlinear and quantum optics.
LASER & PHOTONICS REVIEWS
(2023)
Article
Computer Science, Interdisciplinary Applications
A. Amaricci, L. Crippa, A. Scazzola, F. Petocchi, G. Mazza, L. de Medici, M. Capone
Summary: EDIpack is an exact diagonalization package for solving generic quantum impurity problems, enabling massively parallel computations. Optimizing inter-processors communication and achieving sub-linear scaling are crucial for handling large systems.
COMPUTER PHYSICS COMMUNICATIONS
(2022)
Review
Chemistry, Multidisciplinary
Spiridoula Matsika
Summary: This review focuses on the electronic structure aspects of nonadiabatic processes, discussing the requirements for describing conical intersections and nonadiabatic couplings, the performance of common excited state methods in describing these effects, and recent developments in expanding methodology and implementing nonadiabatic couplings.
Article
Chemistry, Physical
Tobias Schafer, Florian Libisch, Georg Kresse, Andreas Gruneis
Summary: An embedding approach is presented to efficiently handle local electron correlation effects in periodic environments by integrating high-level correlation calculations into low-level ones. The method demonstrates accelerated convergence with respect to the local fragment size and has shown capabilities in accurately calculating adsorption energies of molecules and lattice impurities in solids.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Materials Science, Multidisciplinary
Lorenzo Varrassi, Peitao Liu, Zeynep Ergonenc Yavas, Menno Bokdam, Georg Kresse, Cesare Franchini
Summary: A systematic investigation was conducted on the role of excitonic effects in the optical properties of transition metal oxide perovskites. Optical conductivities and transitions were calculated, with results showing satisfactory agreement between theory and experiment.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Peitao Liu, Carla Verdi, Ferenc Karsai, Georg Kresse
Summary: This study investigates the alpha-beta phase transition of Zr at ambient pressure using on-the-fly machine-learned force fields, successfully reproducing the first-order displacive nature of the phase transition and confirming it through simulated x-ray powder diffraction. The use of singular value decomposition and pseudo inversion of the design matrix is shown to generally improve the machine-learned force field.
PHYSICAL REVIEW MATERIALS
(2021)
Article
Computer Science, Interdisciplinary Applications
Mark E. Turiansky, Audrius Alkauskas, Manuel Engel, Georg Kresse, Darshana Wickramaratne, Jimmy-Xuan Shen, Cyrus E. Dreyer, Chris G. Van de Walle
Summary: This paper presents a first-principles methodology for calculating nonradiative capture rates, emphasizing the impact of point defects on the performance of semiconductor devices. It discusses the approach for evaluating electron-phonon coupling and corrects errors in capture rate calculation.
COMPUTER PHYSICS COMMUNICATIONS
(2021)
Article
Chemistry, Physical
Gilles A. de Wijs, Georg Kresse, Remco W. A. Havenith, Martijn Marsman
Summary: This study benchmarks density functional theory gauge-including projector-augmented-wave (GIPAW) chemical shieldings against molecular shieldings to demonstrate the importance of two-center corrections for GIPAW hydrogen shieldings, finding standard GIPAW to be sufficiently accurate for other nuclei studied. It also shows that GIPAW can be pushed to approach the basis set limit, with small inaccuracies only from shielding contribution caused by surface currents. Comparing GIPAW susceptibilities to converged molecular magnetizabilities helps estimate these inaccuracies.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Carla Verdi, Ferenc Karsai, Peitao Liu, Ryosuke Jinnouchi, Georg Kresse
Summary: Machine-learned interatomic potentials are used to accurately calculate complex materials properties at finite temperatures with first-principles accuracy, but their ability to describe anharmonic properties is still uncertain. A new on-the-fly learning technique based on molecular dynamics and Bayesian inference is employed to generate an interatomic potential capable of describing the thermodynamic properties of zirconia. The study demonstrates that machine-learned potentials offer an accurate and efficient solution for simulating the thermodynamic properties of a wide range of anharmonic materials.
NPJ COMPUTATIONAL MATERIALS
(2021)
Article
Chemistry, Physical
Moritz Humer, Michael E. Harding, Martin Schlipf, Amir Taheridehkordi, Zoran Sukurma, Wim Klopper, Georg Kresse
Summary: This paper uses the direct random-phase approximation (dRPA) to calculate and compare the atomization energies of ten selected molecules in the HEAT set and G2-1 set, using both plane waves and Gaussian-type orbitals. Detailed procedures are described for obtaining highly accurate and well converged results using the projector augmented-wave method and the explicitly correlated dRPA-F12 method. The results show that both approaches agree within chemical accuracy for all considered molecules.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
A. Troester, C. Verdi, C. Dellago, I Rychetsky, G. Kresse, W. Schranz
Summary: In this study, the properties of hard antiphase boundaries in SrTiO3 were investigated using machine-learned force fields. The results showed that the observed domain wall pattern maintained Neel character and the in-plane polarization did not decay to zero, providing evidence for the presence of rotopolar couplings. This approach overcomes the limitations of ab initio simulations and allows for accurate predictions of domain-wall properties at finite temperatures.
PHYSICAL REVIEW MATERIALS
(2022)
Article
Physics, Multidisciplinary
Peitao Liu, Jiantao Wang, Noah Avargues, Carla Verdi, Andreas Singraber, Ferenc Karsai, Xing-Qiu Chen, Georg Kresse
Summary: In this study, a machine-learned force field (MLFF) with near random phase approximation (RPA) accuracy is developed for the prediction of coverage-dependent CO adsorption on the Rh(111) surface. The MLFF is trained through an efficient on-the-fly active learning procedure and a Delta-machine learning approach. The results show that the RPA-derived MLFF can accurately predict the surface energy, adsorption site preference, and adsorption energies of CO on Rh(111) at different coverages, which are in good agreement with experiments. Additionally, the coverage-dependent ground-state adsorption patterns and adsorption saturation coverage are identified.
PHYSICAL REVIEW LETTERS
(2023)
Article
Materials Science, Multidisciplinary
Carla Verdi, Luigi Ranalli, Cesare Franchini, Georg Kresse
Summary: We propose a method to accurately calculate temperature-dependent quantum and anharmonic effects by combining machine-learned potentials and the stochastic self-consistent harmonic approximation. The approach is applied to study the cubic to tetragonal transition in strontium titanate and reveals that anharmonic quantum fluctuations stabilize the paraelectric phase. Additionally, we find that a higher-level treatment of electronic correlation effects using the random phase approximation is necessary for a quantitative understanding of the quantum paraelectric behavior. This approach enables detailed investigations of emergent properties in strongly anharmonic materials beyond density-functional theory.
PHYSICAL REVIEW MATERIALS
(2023)
Article
Chemistry, Physical
Amir Taheridehkordi, Martin Schlipf, Zoran Sukurma, Moritz Humer, Andreas Grueneis, Georg Kresse
Summary: We implement the phaseless auxiliary field quantum Monte Carlo method using the plane-wave based projector augmented wave method and explore its accuracy and feasibility in solid-state applications. Compression of the two-body Hamiltonian using singular value decomposition reduces the computational cost. Consistent correlation energies obtained from both primitive-cell sampling and supercell calculations confirm the accuracy of our implementation. We demonstrate the competitiveness of our implementation in terms of accuracy and computational cost compared to a well-established quantum-chemistry approach.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Correction
Chemistry, Physical
Benjamin Ramberger, Georg Kresse
Summary: This correction article by Benjamin Ramberger et al. provides new insights into the 1D carbon chain and presents corrections based on RPA (Random Phase Approximation).
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Correction
Chemistry, Physical
Benjamin Ramberger, Georg Kresse
Summary: This article is a correction to a previously published paper that discusses new insights into the 1D carbon chain through the use of the RPA method. The authors identified some errors in the original paper and provided corrections.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
Martin Unzog, Alexey Tal, Georg Kresse
Summary: We present an implementation of the Bethe-Salpeter equation (BSE) for core-conduction band pairs within the framework of the projector augmented-wave method. The method is validated by comparing with experiment and other theoretical methods. The results show excellent agreement with experiment, and BSE can reproduce experimental features that are lacking in the supercell core-hole method.
Article
Materials Science, Multidisciplinary
Peitao Liu, Carla Verdi, Ferenc Karsai, Georg Kresse
Summary: In this study, a method for generating MLFFs with beyond DFT accuracy using efficient on-the-fly active learning and Delta machine learning is presented. By training on the random phase approximation, the expensive calculations can be performed on a small number of representative structures, reducing computational cost and enabling MLFFs capable of reproducing high-level quantum mechanical calculations beyond DFT. Successful application in studying the phase transitions of zirconia is demonstrated.