Article
Chemistry, Physical
A. Waigum, J. A. Black, A. Kohn
Summary: A generalization of the hybrid scheme for multireference methods by Saitow and Yanai is presented, which constructs hybrid methods by defining internal and external excitation spaces and evaluating them at different levels of theory. New hybrids are derived and benchmarked, showing improvements in computational complexity and numerical accuracy compared to their non-hybrid parent method. The new separation of excitation space combining singles and doubles excitations into the external space is also tested and found effective.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Soumi Haldar, Abhishek Mitra, Matthew R. Hermes, Laura Gagliardi
Summary: In this study, we investigated the negatively charged nitrogen-vacancy center in diamond using periodic density matrix embedding theory (pDMET). To accurately describe the strongly correlated excited states of the system, we utilized the complete active space self-consistent field (CASSCF) method followed by n-electron valence state second-order perturbation theory (NEVPT2) as the impurity solver. By extrapolating the excitation energies to the nonembedding limit using linear regression, we obtained the first triplet-triplet excitation energy of 2.31 eV and the singlet-singlet transition energy of 1.02 eV, both in agreement with experimental observations. This is the first application of pDMET to a charged periodic system and the first investigation of the NV- defect using NEVPT2 for periodic supercell models.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Maria-Andreea Filip, Alex J. W. Thom
Summary: The development of multireference coupled cluster (MRCC) techniques in electronic structure theory has been challenging due to the complexity in expressing a multiconfigurational wavefunction within the single-reference coupled cluster framework. The multireference-coupled cluster Monte Carlo (mrCCMC) technique, based on the Monte Carlo approach, offers a simpler alternative but needs improvement in accuracy and computational cost. This paper explores incorporating ideas from conventional MRCC to the mrCCMC framework, resulting in methods with increased relaxation of the reference space and a better understanding of solutions to the mrCCMC equations.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Review
Chemistry, Physical
Alessandro Erba, Jacques K. Desmarais, Silvia Casassa, Bartolomeo Civalleri, Lorenzo Dona, Ian J. Bush, Barry Searle, Lorenzo Maschio, Loredana Edith-Daga, Alessandro Cossard, Chiara Ribaldone, Eleonora Ascrizzi, Naiara L. Marana, Jean-Pierre Flament, Bernard Kirtman
Summary: The CRYSTAL program is a quantum-mechanical simulation tool for materials, bridging molecular quantum chemistry and solid state physics. By using atom-centered basis functions and efficient evaluation of the Fock exchange series, it has allowed for a better understanding of various material properties. The program has undergone significant developments in the past five years and has been applied in various fields.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Teffanie Goh, Riddhish Pandharkar, Laura Gagliardi
Summary: In this study, various theoretical methods were successfully used to investigate an optically addressable molecular qubit and four other V3+ complexes. The results suggest that the ligands have minimal impact on the spin properties of the molecules, making them potential candidates for optically addressable qubits.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Riddhish Pandharkar, Matthew R. Hermes, Christopher J. Cramer, Laura Gagliardi
Summary: This paper introduces a localized active space-state interaction (LASSI) method that can reduce the computational cost of multireference calculations and improve interpretability. The method utilizes the local nature of electron-electron correlation and expresses the composite wave function as an antisymmetrized product of unentangled wave functions in local active subspaces. The use of LASSI allows for more compact and selective inclusion of states, providing a quantitative analysis of specific types of interactions.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Inorganic & Nuclear
Maria Drosou, Christiana A. Mitsopoulou, Dimitrios A. Pantazis
Summary: A detailed study of spin-state energetics for eight Mn(III) and Mn(II) SCO complexes was conducted using a coupled cluster theory approach, leading to the proposal of a robust and efficient computational protocol for studying spin crossover systems. The results highlighted the limitations of multireference wavefunction-based and DFT approaches in providing a balanced description of spin-state energetics for these complexes, underscoring the proposed DLPNO-CCSD(T) protocol as a generally applicable reference-quality quantum chemical method.
Article
Chemistry, Multidisciplinary
Patrick K. Tamukong, Mark R. Hoffmann
Summary: The GVVPT2 method was used to study the low-lying electronic states of Ni-2, revealing a large number of low-lying states correlated with the D-3(3) + D-3(3) dissociation limit. The ground state was identified as X(1)Gamma(g), with spectroscopic constants in agreement with experimental values when scalar relativistic effects were considered.
FRONTIERS IN CHEMISTRY
(2021)
Article
Chemistry, Physical
Andreas Erbs Hillers-Bendtsen, Phillip Gustav Iuel Lunoe Dunweber, Lars Henrik Olsen, Kurt Mikkelsen
Summary: The study found that by making simple modifications to the bridgehead of bicyclic dienes, it is possible to significantly increase the energy storage without compromising other crucial properties. This method shows promise.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Engineering, Environmental
Jing Dai, Ziqian Wang, Kewen Chen, Dahu Ding, Shengjiong Yang, Tianming Cai
Summary: In this study, the role of carbon materials in periodate based advanced oxidation processes (PI-AOPs) was investigated. A metal-free biochar catalyst was found to significantly enhance the degradation of bisphenol A (BPA). Two types of biochar catalysts, BC350 and BC800, exhibited distinct behaviors for PI activation, suggesting different mechanisms. BC350 was believed to activate PI through a surface hydroxyl group-induced nonradical pathway, while BC800 showed a carbon-mediated electron-transfer mechanism. These findings provide new insights into the nonradical pathways in biochar catalyzed PI-AOPs and enhance the development and application of PI-AOPs in environmental remediation.
CHEMICAL ENGINEERING JOURNAL
(2023)
Article
Chemistry, Physical
Shouzhi Wang, Huaping Zhao, Songyang Lv, Hehe Jiang, Yongliang Shao, Yongzhong Wu, Xiaopeng Hao, Yong Lei
Summary: Transition metal oxides are promising materials for sodium-ion capacitors, but their conductivity and structure limitations hinder their development. Core-shell nickel-cobalt oxysulfide nanowires were synthesized with enhanced sodium ion adsorption, redox reaction, and accommodation of volume changes. The unique structure provided abundant channels for fast sodium ion transfer, resulting in high reversible sodium ion storage capacity and excellent cycling performance. Such design strategy using bimetallic compounds offers high-performance anodes for sodium storage.
ADVANCED ENERGY MATERIALS
(2021)
Article
Chemistry, Physical
Jan-Niklas Boyn, David A. Mazziotti
Summary: Accurately resolving the chemical properties of strongly correlated systems requires the use of electronic structure theories that account for both multi-reference and dynamic correlation effects. This study explores the use of density functional theory as a cost-effective alternative to generate reference orbitals for post-configuration-interaction dynamic correlation calculations.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Michal Hapka, Agnieszka Krzeminnska, Marcin Modrzejewski, Michal Przybytek, Katarzyna Pernal
Summary: This article proposes an algorithm for accurately and efficiently predicting dispersion interactions in excited-state complexes. The algorithm takes into account the complex nature of electron correlation effects and scales with system size. Numerical illustrations using the algorithm reveal that dispersion energy may play a significant role in stabilizing excited-state complexes.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Agnieszka Stanczak, Jakub Chalupsky, Lubomir Rulisek, Michal Straka
Summary: In this study, the performance of various composite computational protocols for CBC sites was comprehensively calibrated and evaluated. Several calibrated DFT functionals were selected for the study of [Cu2O2] inorganic systems.
Article
Chemistry, Physical
Lixin Lu, Hang Hu, Andrew J. Jenkins, Xiaosong Li
Summary: As relativistic corrections become stronger for late-row elements, the fully perturbative treatment may not be adequate for accurate descriptions of chemical properties. In this work, a determinant-based Kramers-unrestricted exact-two-component multi-reference second-order perturbation method is introduced, which includes relativistic corrections with a perturbative dynamic correlation.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Attila Tajti, Levente Tulipan, Peter G. Szalay
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2020)
Article
Chemistry, Physical
Hans Lischka, Ron Shepard, Thomas Mueller, Peter G. Szalay, Russell M. Pitzer, Adelia J. A. Aquino, Mayzza M. Araujo do Nascimento, Mario Barbatti, Lachlan T. Belcher, Jean-Philippe Blaudeau, Itamer Borges, Scott R. Brozell, Emily A. Carter, Anita Das, Gergely Gidofalvi, Leticia Gonzalez, William L. Hase, Gary Kedziora, Miklos Kertesz, Fabris Kossoski, Francisco B. C. Machado, Spiridoula Matsika, Silmar A. do Monte, Dana Nachtigallova, Reed Nieman, Markus Oppel, Carol A. Parish, Felix Plasser, Rene F. K. Spada, Eric A. Stahlberg, Elizete Ventura, David R. Yarkony, Zhiyong Zhang
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Chemistry, Physical
Devin A. Matthews, Lan Cheng, Michael E. Harding, Filippo Lipparini, Stella Stopkowicz, Thomas-C Jagau, Peter G. Szalay, Juergen Gauss, John F. Stanton
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Chemistry, Physical
Balazs Kozma, Attila Tajti, Baptiste Demoulin, Robert Izsak, Marcel Nooijen, Peter G. Szalay
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2020)
Article
Chemistry, Physical
Balazs Kozma, Romain Berraud-Pache, Attila Tajti, Peter G. Szalay
Article
Chemistry, Physical
Attila Tajti, Balazs Kozma, Peter G. Szalay
Summary: This paper evaluates the performance of spin-component-scaled methods for charge-transfer electronic states, showing their capability to reduce large errors and outperform standard methods in many cases. The study recommends spin-component-scaled variants as a method of choice for investigating CT states.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Editorial Material
Chemistry, Physical
Devin A. Matthews, Lan Cheng, Ajith Perera, Peter G. Szalay
Article
Chemistry, Physical
David P. Jelenfi, Attila Tajti, Peter G. Szalay
Summary: The electron transport through the single-molecule junction of benzene-1,4-diamine is studied using ab initio quantum-classical molecular dynamics of electron attached states. The role of molecular vibrations in facilitating transport is shown through normal mode analysis, with periodic alterations of molecule-electrode interactions. No significant differences are found between results provided by different excited state models.
Article
Chemistry, Multidisciplinary
Bonis Barcza, Adam B. Szirmai, Katalin J. Szanto, Attila Tajti, Peter G. Szalay
Summary: The ground state intermolecular potential of bimolecular complexes of N-heterocycles is analyzed for the impact of individual terms in the interaction energy as provided by various theories. Two methods, which do not rely on predefined force fields, are found to have good agreement with the reference results and are excellent candidates for ab initio modeling.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2022)
Article
Chemistry, Physical
Ahmed Shaalan Alag, David P. Jelenfi, Attila Tajti, Peter G. Szalay
Summary: The CC2 and ADC(2) wave function models and their spin-component scaled modifications were used to study affinities, making it possible to utilize existing quantum chemistry codes with minimal modifications. Benchmark calculations on various sets showed that using spin-scaled methods can achieve accuracy at a fraction of the computational cost and outperform other electron propagator approaches.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Bence Hegely, Adam B. Szirmai, David Mester, Attila Tajti, Peter G. Szalay, Mihaly Kallay
Summary: The performance of multilevel quantum chemical approaches for modeling electronic excited states was studied. The results show that the most reliable method is the local domain-based ADC(2), while the ONIOM-ME and ONIOM-EE methods are the least robust.
JOURNAL OF PHYSICAL CHEMISTRY A
(2022)
Article
Chemistry, Physical
Bonis Barcza, Adam B. Szirmai, Attila Tajti, John F. Stanton, Peter G. Szalay
Summary: Although Coupled-Cluster methods accurately describe excited electronic states, their computational costs limit their application. This study focuses on fragment-based approaches for noncovalently bound molecular complexes with interacting chromophores. Two approaches were tested for describing the states localized on the fragments with electrostatic interactions, Pauli repulsion, and dispersion effects. The effective fragment potential method was found to provide an adequate correction. Electrostatic contributions were sufficient for modeling the interaction of the localized chromophores.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Physical
Attila Tajti, Peter G. Szalay, Roman Kochanov, Vladimir G. Tyuterev
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2020)
Article
Chemistry, Physical
Thiago Messias Cardozo, Andre Pessoa Galliez, Itamar Borges, Felix Plasser, Adelia J. A. Aquino, Mario Barbatti, Hans Lischka
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2019)
Article
Biochemistry & Molecular Biology
Farhan Siddique, Cassio P. Silva, Gustavo T. Medeiros Silva, Hans Lischka, Frank H. Quina, Adelia J. A. Aquino
PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES
(2019)