Article
Mathematics, Applied
Shirin Panahi, Isaac Klickstein, Francesco Sorrentino
Summary: The article proposed a canonical transformation method to analyze the stability of cluster synchronization in networks, with advantages of decoupling the problem, studying stability of different node partitions, and parameterizing the problem in a small number of parameters.
Article
Chemistry, Physical
Robert Littlejohn, Jonathan Rawlinson, Joseph Subotnik
Summary: This article discusses the use of parallel transport to create a diabatic basis. The advantages of the parallel-transported basis include the ease of carrying out Taylor series expansions and the close relationship between the derivative couplings and the curvature. These are important for analytic treatments of the nuclear Schrodinger equation. The article also explores the relationship between the parallel-transported basis and the singular-value basis.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Soichiro Nishio, Yuki Kurashige
Summary: We demonstrate the importance of dynamical electron correlation effect in diabatic electron-exchange processes in molecular aggregates. A multireference perturbation theory with a large active space is performed using an efficient low-rank approximation. It is found that the direct term of diabatic couplings is not sufficient to explain the kinetic rates of electron-exchange processes, such as singlet fission, triplet-triplet annihilation, and triplet exciton transfer, but these processes are efficiently mediated by low-lying charge transfer states if the two molecules are in close proximity. It is also observed that regardless of the distance between the molecules, the direct term is significantly underestimated without the dynamical electron correlation.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Biochemistry & Molecular Biology
Grzegorz Skrzynski, Monika Musial
Summary: Accurate potential energy curves for the twenty-two electronic states of LiRb are determined using first principle calculations and the multireference coupled cluster scheme within the Fock space formalism. Continuous PECs spanning the entire range of interatomic distances are successfully computed, and the spectroscopic characteristics of various electronic states, including relativistic corrections, are presented.
Article
Chemistry, Physical
Piotr Jankowski, Ewelina Grabowska, Krzysztof Szalewicz
Summary: The study shows that the contributions of coupled clusters iterative triple and noniterative quadruple electron excitations are crucial for the potential energy surfaces of van der Waals molecules, even though these contributions are relatively small. Including these effects can significantly alter the anisotropy of the PES, leading to qualitative agreement between theory and experiment results.
Article
Chemistry, Physical
D. O. Kashinski, J. Bohnemann, A. P. Hickman, D. Talbi
Summary: The study presents a diabatic representation of the potential energy curves for the (4)Pi states of SH, using MRCI calculations to determine high-accuracy adiabatic PECs for both SH and SH+. The adiabatic PECs exhibit avoided crossings due to Rydberg-valence mixing. Disentanglement of the valence autoionizing and Rydberg states of SH is achieved through block diagonalization method to construct a diabatic Hamiltonian, ensuring smooth variation and consistency of chemically significant molecular orbitals across different geometries.
THEORETICAL CHEMISTRY ACCOUNTS
(2021)
Article
Chemistry, Physical
Yafu Guan, David R. Yarkony, Dong H. Zhang
Summary: In this work, the PIP-NN approach is used to construct a quasi-diabatic Hamiltonian for systems with non-Abelian symmetries, providing a flexible and accurate method for studying complex systems. The PIP-NN diabatic ansatz not only preserves correct symmetry, but also accurately reproduces electronic structure data, demonstrating excellent fits and reproducing adiabatic energies, energy gradients, and derivative couplings effectively.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Monika Musial, Anna Bewicz, Stanislaw A. Kucharski
Summary: Accurate potential energy curves for the 26 lowest lying electronic states of the sodium dimer were obtained using a first principle size-extensive multireference coupled cluster method. The (2,0) sector of the Fock space was utilized to accurately describe the attachment of two electrons to the reference system, allowing the doubly ionised sodium dimer to be used as a reference for the calculations. This approach resulted in correct interatomic potential descriptions for all bond lengths and showed good agreement with experimental data. The inclusion of relativistic corrections at the second-order Douglass-Kroll level significantly improved the accuracy of computed excitation and dissociation energies.
Article
Chemistry, Multidisciplinary
Junzi Liu, Lan Cheng
Summary: The article reviews the development of relativistic coupled-cluster and equation-of-motion coupled-cluster methods, focusing on recent efforts to improve computational efficiency and extend the methods to molecules containing heavy elements. Future directions for the development of these methods are also discussed.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2021)
Article
Chemistry, Physical
Alejandro Gallo, Felix Hummel, Andreas Irmler, Andreas Grueneis
Summary: This study presents an implementation of EOM-CCSD theory for studying F-centers in alkaline earth oxides, demonstrating good agreement with experimental results. The convergence of calculated electronic excitation energies with respect to orbital basis set and system size, as well as the use of extrapolation techniques to reduce finite size errors, are discussed. The calculated emission energies responsible for photoluminescence properties are also compared to available experimental and theoretical results.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Zhanli Cao, Xiaojun Zhou, Yunguang Zhang, JianXia Qi
Summary: The effects of spin-orbit coupling in halohydride cations were investigated using the EOM-SOC-CC method, with SOC being increasingly important for heavier cations. An approximation method, EOM-SOC-CC-a, was introduced to reduce computational effort for ionization potentials while maintaining accuracy. Both methods provide satisfactory results for the electronic structure and IPs calculations.
CHEMICAL PHYSICS LETTERS
(2021)
Article
Quantum Science & Technology
Rongxin Xia, Sabre Kais
Summary: VQE is considered a major potential application of near term quantum computing for electronic structure calculations. The UCCSD VQE ansatz has achieved high accuracy, but requires extra terms for parity when using the Jordan-Wigner transformation. The proposed VQE ansatz based on particle preserving exchange gate has a gate complexity up-bounded to O(n(4)) for all-to-all connectivity, and provides very accurate results for simple molecular systems.
QUANTUM SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Physical
Sahil Gulania, Eirik F. Kjonstad, John F. Stanton, Henrik Koch, Anna I. Krylov
Summary: The EOM-DEA-CCSD method has been implemented for treating electronic structure patterns involving two electrons in many orbitals. This method has demonstrated the capability to handle diradicals, bond-breaking, and certain types of conical intersections.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Engineering, Geological
Penghua Teng, Fredrik Johansson, J. Gunnar I. Hellstrom
Summary: Rock block removal is a prevalent physical mechanism for rock erosion and has significant implications for the stability of dam foundations and spillways. However, the understanding of block removal is still inadequate due to the complex interactions among block characteristics, hydraulic forces, and erosive processes. This study presents a coupled computational fluid dynamics-discrete element model (CFD-DEM) approach to simulate the removal processes of protruding rock blocks under different flow conditions, considering the effect of discontinuity orientation. The simulation results reproduce the observed effects of discontinuity orientation on critical flow velocity and block motion trajectory, providing insights into the block removal process.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2023)
Article
Computer Science, Artificial Intelligence
Huazhu Chen, Weiwei Wang, Shousheng Luo
Summary: Multi-view subspace clustering aims to segment high-dimensional multi-source data into corresponding subspaces to uncover latent low-dimensional structures. This paper proposes a new method, CBDMSC, which learns view-specific affinity matrices and a common cluster indicator matrix jointly, and enforces a block diagonal inducing regularity to enhance clustering accuracy.
DATA MINING AND KNOWLEDGE DISCOVERY
(2022)
