Article
Chemistry, Physical
L. Urban, T. H. Thompson, C. Ochsenfeld
Summary: An empirically scaled version of the MP2-F12 method is introduced, which requires a basis set dependent scaling factor determined by fitting a set of test molecules, and accurately describes a wide range of systems. The new method not only shows remarkably good performance on the S22 and L7 test sets, but also exhibits distinct speedups compared to the unscaled F12 correction for all considered systems.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Tamar Goldzak, Xiao Wang, Hong-Zhou Ye, Timothy C. Berkelbach
Summary: In this study, the performance of spin-component-scaled second-order Møller-Plesset perturbation theory (SCS-MP2) for the prediction of lattice constant, bulk modulus, and cohesive energy of simple covalent and ionic semiconductors and insulators was investigated. The results show that SCS-MP2 and the simpler scaled opposite-spin MP2 (SOS-MP2) method yield significantly improved predictions compared to MP2, with mean absolute errors smaller than those of leading density functionals. The reparameterization of the spin scaling parameters suggests good transferability and potential applications to surface chemistry on insulators.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
M. A. Ambroise, F. Sacchetta, D. Graf, C. Ochsenfeld, A. Dreuw
Summary: A novel local approach is proposed for the quantum-chemical computation of excited states by extending the atomic-orbital formulation to the second-order algebraic diagrammatic construction scheme using Laplace transform. The CDD-DF-SOS-ADC(2) method achieves substantial reduction in computational effort by exploiting the sparsity of two-electron repulsion integrals, atomic ground-state density matrix, and atomic transition density matrix. It is shown that asymptotically linear scaling can be achieved for linear carboxylic acids, and sub-cubic scaling can be achieved for electron-dense systems with sparse transition density. The memory footprint and accuracy of the method are also explored.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
F. Sacchetta, D. Graf, H. Laqua, M. A. Ambroise, J. Kussmann, A. Dreuw, C. Ochsenfeld
Summary: This article presents an atomic-orbital reformulation of the coupled cluster model, extending its applicability to molecules with hundreds of atoms and triple-zeta basis sets. The method achieves sub-quadratic computational scaling through sparse linear algebra and an attenuated Coulomb metric, while reducing the prefactor with Cholesky decomposition of the density matrix.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Naoki Negishi, Daisuke Yokogawa
Summary: In this study, the second-order Moller-Plesset perturbation theory combined with the reference interaction site model was successfully used to predict the activation free energies of a Diels-Alder reaction, with results within 2 kcal/mol of experimental data.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Physical
Christopher J. N. Coveney, David P. P. Tew
Summary: We propose a scalable single-particle framework for treating electronic correlation in molecules and materials based on Green's function theory. By introducing the Goldstone self-energy, we derive a size-extensive Brillouin-Wigner perturbation theory from the single-particle Green's function. This new ground state correlation energy, named Quasi-Particle MP2 theory (QPMP2), avoids the characteristic divergences in strongly correlated systems present in second-order Moller-Plesset perturbation theory and Coupled Cluster Singles and Doubles methods, and demonstrates excellent performance in reproducing exact ground state energy and properties of the Hubbard dimer as well as larger Hubbard models.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Chemistry, Applied
Jongmin Park, Jiyeong Cho, Myung-June Park, Won Bo Lee
Summary: In this study, computational chemistry and microkinetic modeling methods were used to analyze the reaction pathways of DME synthesis by methanol dehydration over a H-zeolite catalyst. The dissociative pathway was identified as the dominant pathway, with the reaction CH3OHCH3-Z -> CH3OCH3-H-Z being the rate-determining step. The developed model was also used to investigate the effects of temperature on the site fractions over the catalyst.
Article
Chemistry, Inorganic & Nuclear
Kai Wang, Shao-Zheng Fang, Zheng Fan, Hong-Yuan Zhao, Lin Miao, Guang-Jia Yin, Ramiro Moro, Lei Ma
Summary: The electric polarizability of the aluminum atom has been an important benchmark in polarizability measurements. Previous values had a large discrepancy with experimental measurements, but this study presents a more accurate computation using various ab initio methods. The recommended value reconciles the theoretical and experimental values, reaffirming its reliability for future experiments.
JOURNAL OF CLUSTER SCIENCE
(2023)
Article
Chemistry, Physical
Kimberly J. Daas, Derk P. Kooi, Nina C. Peters, Eduardo Fabiano, Fabio Della Sala, Paola Gori-Giorgi, Stefan Vuckovic
Summary: Noncovalent interactions are crucial in various fields and a methodology for improving pure quantum-chemical simulations of these interactions has been proposed. The methodology combines interpolation, regularization, and spin-scaling strategies to enhance accuracy and competitiveness for noncovalent interactions.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2023)
Article
Chemistry, Physical
Marcos Casanova-Paez, Lars Goerigk
Summary: This study presents new LC double hybrids with SCS/SOS that demonstrate further improvement over previously published results and methods, showing highly efficient and robust performance for vertical excitation energies. Among them, the SCS/SOS-omega PBEPP86 and SCS/SOS-omega B88PP86 functionals are identified as four of the most accurate and robust methods, recommended for future applications.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Materials Science, Multidisciplinary
Xuechao Zhai
Summary: This paper discusses the phenomenon of layered opposite Rashba spin-orbit coupling (LO-RSOC) in bilayer graphene due to inversion symmetry. The loss of spin chirality in the momentum space caused by LO-RSOC makes it difficult to experimentally confirm its existence through the band structure. To address this issue, the authors propose methods to identify LO-RSOC by breaking the inversion symmetry through gating or breaking the time-reversal symmetry through a magnetic field. Moreover, the authors observe a transition in band topology as the system deviates from the LO Rashba state and suggest a candidate material for LO-Rashba systems.
Article
Chemistry, Physical
Yuqi Wang, Yang Guo, Frank Neese, Edward F. Valeev, Wei Li, Shuhua Li
Summary: In this article, a series of explicitly correlated local correlation methods developed under the cluster-in-molecule (CIM) framework are presented. These methods allow F12 calculations of large molecules on a single node. The authors used these methods to investigate the relative stability between extended and folded alkane, the stability of different structures of polyglycine, and the binding energies of host-guest complexes. The results demonstrate the promising potential of combining CIM with F12 methods for studying large molecules.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2023)
Article
Materials Science, Multidisciplinary
Yanqiang Han, Jinyun Liu, Jinjin Li
Summary: The research focuses on the crystal structure and phase transition of solid carbon monoxide under high-pressure and low-temperature conditions using high-precision MP2 theory. Results show that the proposed method accurately calculates the atomic structures, Raman spectra, and phase transition conditions, offering potential for exploring new crystals and important applications in experiments.
MATERIALS TODAY COMMUNICATIONS
(2021)
Article
Physics, Condensed Matter
Shubhajyoti Mohapatra, Avinash Singh
Summary: The study investigates the pseudo-spin rotation symmetry of different Coulomb interaction terms under SU(2) transformation in pseudo-spin space. It was found that the Hund's coupling and pair-hopping interaction terms systematically break the pseudo-spin rotation symmetry, leading to the formation of easy x-y plane anisotropy and magnon gap.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2021)
Article
Optics
Sergey Krasnoshchekov, Vladimir B. Laptev, Ivan K. Gainullin
Summary: The study investigates the structure and properties of Bis(trifluoromethyl)ketene using infrared spectroscopy, combining experimental and theoretical calculations to obtain fairly accurate results.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2021)
Article
Chemistry, Physical
Daniel G. A. Smith, Lori A. Burns, Andrew C. Simmonett, Robert M. Parrish, Matthew C. Schieber, Raimondas Galvelis, Peter Kraus, Holger Kruse, Roberto Di Remigio, Asem Alenaizan, Andrew M. James, Susi Lehtola, Jonathon P. Misiewicz, Maximilian Scheurer, Robert A. Shaw, Jeffrey B. Schriber, Yi Xie, Zachary L. Glick, Dominic A. Sirianni, Joseph Senan O'Brien, Jonathan M. Waldrop, Ashutosh Kumar, Edward G. Hohenstein, Benjamin P. Pritchard, Bernard R. Brooks, Henry F. Schaefer, Alexander Yu. Sokolov, Konrad Patkowski, A. Eugene DePrince, Ugur Bozkaya, Rollin A. King, Francesco A. Evangelista, Justin M. Turney, T. Daniel Crawford, C. David Sherrill
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Chemistry, Organic
Selcuk Essiz, Ugur Bozkaya
JOURNAL OF ORGANIC CHEMISTRY
(2020)
Article
Chemistry, Physical
Suleyman Aykut Servan, Asli Unal, Busra Hamarat, Ugur Bozkaya
JOURNAL OF PHYSICAL CHEMISTRY A
(2020)
Article
Chemistry, Physical
Ugur Bozkaya, Asli Unal, Yavuz Alagoz
JOURNAL OF CHEMICAL PHYSICS
(2020)
Article
Chemistry, Physical
Ugur Bozkaya
Summary: Efficient computation of molecular integrals and their derivatives is crucial in modern quantum chemistry for property evaluation. The Molint application programming interface (API) framework reported in this study provides a smooth approach to calculate these integrals and their first derivatives, including overlap, dipole, kinetic, potential, 2-index, and 3-index integrals. Molint is a C++/Fortran hybrid code, free software, and offers shared-memory parallel programming techniques for increased efficiency. Results demonstrate Molint as an efficient and user-friendly API for molecular integral computation.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2021)
Article
Chemistry, Physical
Yavuz Alagoz, Asli unal, Ugur Bozkaya
Summary: The DF-OCCD(T) and DF-OCCD(T)(?) methods provide significantly lower computational costs compared to the conventional OCCD(T), making them very helpful for the study of single bond-breaking problems. Additionally, the DF-OCCD(T)(?) method shows dramatic improvements over the CCSD(T) method, making it promising for challenging chemical systems where CCSD(T) fails.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Chemistry, Organic
Ilknur Polat, Selcuk Essiz, Ugur Bozkaya, Emine Salamci
Summary: This study describes the synthesis of several target compounds starting from cis-9-azabicyclo[6.2.0]dec-6-en-10-one, and analyzes the reaction mechanism and stereochemistry using DFT calculations and NMR spectroscopy.
BEILSTEIN JOURNAL OF ORGANIC CHEMISTRY
(2022)
Article
Chemistry, Physical
Ugur Bozkaya, Betuel Ermis, Yavuz Alagoz, Asli Unal, Ali Kaan Uyar
Summary: MacroQC is a quantum chemistry software that specializes in high-accuracy computations and large-scale chemical applications. It offers a wide range of many-body perturbation theory and coupled-cluster methods, with particular efficiency in analytical gradients. MacroQC also provides limited interoperability with other software and has a developer-friendly plugin system. The software's distinctive feature is its linear-scaling systematic molecular fragmentation method, which allows the application of high-level post-Hartree-Fock methods to large-sized molecular systems.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Betul Ermis, Emel Ekinci, Ugur Bozkaya
Summary: Accurate computation of electron affinities (EAs) within 0.10 eV using the EKT-CCSD(T) method has been achieved, showing mean absolute errors (MAEs) of 0.05, 0.08, and 0.09 eV for different test sets. The EKT method also presents a significant advantage in the computation of ionization potentials (IPs) by providing them for free in an analytic gradient computation, reducing the need for separate computations.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2021)
Article
Chemistry, Physical
Asli Unal, Ugur Bozkaya
Summary: The study presents an efficient implementation of the DF-EOM-CCSD method, which significantly accelerates the calculation of excitation energies and reduces computational costs by improving the algorithm for the PPL term and introducing a hybrid DF/CD approach. The results show that this implementation is more efficient compared to RI-EOM-CCSD, especially for large molecular systems.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Multidisciplinary
A. Altas, D. D. Gultekin, M. Acar, E. Cucu, A. Karatay, A. Elmali, A. Atalay, C. A. Demircan, U. Bozkaya, C. Kazaz, E. Sahin, O. . A. Bozdemir
Summary: The positions of electron-releasing and withdrawing groups on perylene monoimides (PMIs) have a significant influence on their photophysical properties. The current modification methods for PMI have limitations, making it important to synthesize PMIs through alternative approaches.
MATERIALS TODAY CHEMISTRY
(2022)
Article
Chemistry, Physical
Stefan Behnle, Robert Richter, Luca Voelkl, Paul Idzko, Andre Foerstner, Ugur Bozkaya, Reinhold F. Fink
Summary: This study utilizes the Retaining the Excitation Degree - Moller-Plesset (REMP) and Orbital Optimized REMP (OO-REMP) hybrid perturbation theories to predict molecular properties. The results show that the OO-REMP approach provides highly accurate results, with predictions of bond lengths, vibrational wavenumbers, and dipole moments matching experimental or accurate calculation data within a small margin of error. The study also finds that a mixing ratio of 20%:80% Moller-Plesset:Retaining the Excitation Degree consistently yields the best results.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Physical
Ugur Bozkaya, Betul Ermis
Summary: This study reports the implementation of an efficient linear-scaling coupled-cluster method, which has promising applications in computational chemistry. By revising the handling of nonbonded interactions and introducing a new fragmentation algorithm, comparable results to canonical methods can be obtained. Additionally, for large chemical systems, higher bonded levels and nonbonded levels are recommended for improved accuracy.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Ozlem Gundogdu, Abdurrahman Atalay, Neslihan Celebioglu, Baris Anil, Ertan Sahin, Gulsah Sanli-Mohamed, Ugur Bozkaya, Yunus Kara
Summary: The ring-opening reactions of (1aS,2S,6bR)-5-ethyl-2-hydroxyhexahydro-4H-oxireno[2,3-e]isoindole-4,6(5H)-dione were investigated under mild conditions, and C-2 selective ring-opening products were obtained with nucleophilic additions. The structure of (3aS,4R,5R,6S,7aS)-5-chloro-2-ethyl-4,6-dihydroxyhexahydro-1H-isoindole-1,3(2H)-dione was determined through X-Ray diffraction analysis. The regioselectivity in the ring opening reaction of epoxy alcohols was explained by theoretical computations.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Chemistry, Organic
Selcuk Essiz, Ugur Bozkaya
Summary: Computational study on AIBN-initiated aerobic oxidative cleavage of alkenes showed that the proposed dioxetane derivatives formation barrier is too high under the reaction conditions. The reaction starts with the peroxyl radical 9 and not the isobutyronitrile radical 2. The experimental results and the study findings are in agreement regarding the mechanism of aerobic oxidative cleavage.
ORGANIC & BIOMOLECULAR CHEMISTRY
(2021)