Article
Chemistry, Physical
Fabijan Pavosevic, Zhen Tao, Sharon Hammes-Schiffer
Summary: The nuclear quantum effects are incorporated into quantum chemistry calculations using the nuclear-electronic orbital (NEO) approach, which includes both traditional and t1-transformed NEO coupled cluster methods with a density fitting scheme. The NEO-DF-CCSD method, with enhanced computational efficiency, accurately predicts proton affinities and successfully predicts the energy ordering of protonated water tetramers with multiple quantum protons. This work showcases the capabilities of the NEO-DF-CCSD method and lays the foundation for future developments and applications.
JOURNAL OF PHYSICAL CHEMISTRY LETTERS
(2021)
Article
Chemistry, Physical
Zohreh Amanollahi, Lukas Lampe, Moritz Bensberg, Johannes Neugebauer, Milica Feldt
Summary: In this study, the accuracy of the LMOMO scheme and WF-in-DFT embedding for predicting reaction energies and barriers of transition metal reactions was investigated. The accuracy was analyzed by applying manual and direct orbital selection methods. Benchmark tests on 30 closed shell reactions involving 16 different transition metals were conducted. Guidelines for orbital selection and settings for accurate results within an error of 2 kcal mol(-1) compared to local coupled cluster were proposed. LMOMO was found to provide more reliable relative energies for small embedded regions than WF-in-DFT embedding.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Materials Science, Multidisciplinary
S. Bae, Y-G Kang, M. Khazaei, K. Ohno, Y-H Kim, M. J. Han, K. J. Chang, H. Raebiger
Summary: Transition metal compounds are challenging for ab initio calculations due to the localized nature of d electrons, leading to errors in electronic and magnetic properties. This study used density functional theory to calculate 22 carbide MXenes with different methods, revealing new ground-state structures and magnetic states. Various methods were compared to improve the reliability of theoretical studies on MXenes.
MATERIALS TODAY ADVANCES
(2021)
Article
Chemistry, Physical
Sebastian Hoefener
Summary: The KOALA program is an ab initio code that focuses on wavefunction embedding methods and uses Gaussian-type basis sets. It features a Davidson solver for linear response in coupled-cluster methods and density functional theory, as well as solving Z-vector equations for orbital-relaxed molecular properties. With frozen-density embedding, it can compute anisotropic environment effects without the scaling issues of conventional methods. The program is efficient for systems with hundreds of atoms, which can be divided into smaller subsystems.
INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY
(2021)
Article
Chemistry, Multidisciplinary
Maria Drosou, Dimitrios A. Pantazis
Summary: The debate over the electronic and geometric structures of the water-oxidizing complex of photosystem II before dioxygen evolution is ongoing. Recent studies have presented contradictory redox formulations for the Mn4CaOx cofactor in the S-3 state, leading to uncertainty about the O-O bond formation in the catalytic cycle. By employing advanced theoretical calculations, researchers were able to evaluate different models for the S-3 state of the oxygen-evolving complex and assess the accuracy of lower-level theoretical approaches.
CHEMISTRY-A EUROPEAN JOURNAL
(2021)
Article
Chemistry, Physical
Kohei Tada, Hiroyuki Ozaki, Koji Fujimaru, Yasutaka Kitagawa, Takashi Kawakami, Mitsutaka Okumura
Summary: The study found that surface interactions can tune chemical indices and that weak adsorption onto ionic solids with charge-dipole interactions can enhance diradical character.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Niklas Niemeyer, Patrick Eschenbach, Moritz Bensberg, Johannes Toelle, Lars Hellmann, Lukas Lampe, Anja Massolle, Anton Rikus, David Schnieders, Jan P. Unsleber, Johannes Neugebauer
Summary: SERENITY is an open-source quantum chemistry software that focuses on quantum-mechanical multilevel and embedding approaches. This study provides an overview of the developments in SERENITY since its original publication in 2018, including efficient electronic-structure methods for ground and excited states. SERENITY's modular structure allows for combination with density-functional theory-based embedding through various practical realizations and variants of subsystem DFT.
WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE
(2023)
Article
Chemistry, Physical
Alexander Bakulin, Sergey S. Kulkov, Svetlana E. Kulkova
Summary: In this study, analytic expressions for the temperature-dependent diffusion coefficient of oxygen in the alpha 2-Ti3Al alloy were obtained using Landman's method. The estimation of oxygen diffusion coefficient, pre-exponential factor, and activation energy was performed using migration barriers calculated by the first principle method within density functional theory. The validated method showed good agreement between the calculated diffusion coefficient of oxygen and available experimental data and theoretical results obtained within statistical approach.
Article
Chemistry, Multidisciplinary
Hong Fang, Huta Banjade, Deepika, Puru Jena
Summary: Transition metal atoms exhibit multiple oxidation states and rich chemistry due to unfilled d-shells. Zinc, typically classified as a transition metal, shows a different chemical behavior as its filled 3d(10) shell does not participate in reactions. Interacting with certain stable super-electrophilic trianions can lead to zinc exhibiting different oxidation states, as evidenced by significant binding energies and altered bonding characteristics.
Article
Chemistry, Physical
Arthur Hagopian, Marie-Liesse Doublet, Jean-Sebastien Filhol, Tobias Binninger
Summary: Computational studies of electrochemical interfaces based on density-functional theory are vital for energy conversion and storage research. The homogeneous background method simplifies charge calculations in DFT simulations, with an advanced version now eliminating the need for certain specifications, allowing for versatile applications. Results show excellent agreement between the advanced HBM and the Poisson-Boltzmann model for charged interfaces in high-dielectric-constant solvents.
JOURNAL OF CHEMICAL THEORY AND COMPUTATION
(2022)
Article
Chemistry, Physical
Anish Chakraborty, Soumi Tribedi, Rahul Maitra
Summary: Fragmentation-based methods allow for electronic structure calculations of large chemical systems by partitioning them into smaller fragments. In this study, a dual exponential operator-based coupled cluster theory within the fragment molecular orbital (FMO) framework is developed and benchmarked to account for high-rank electronic correlation. The method involves constructing zeroth order reference determinants for each fragment and fragment pair, inducing dynamical correlation through a dual exponential ansatz, and including single and double excitations through rank-one and rank-two cluster operators. The accuracy of the method is demonstrated through numerical applications on various systems.
JOURNAL OF CHEMICAL PHYSICS
(2022)
Article
Chemistry, Multidisciplinary
Simone Grillo, Olivia Pulci, Ivan Marri
Summary: In this work, the electronic and optical properties of 2D tellurene in different allotropic forms and with varying number of layers are investigated using ab initio Density Functional Theory calculations. Exciton binding energies and radii are estimated using a 2D analytical model. The results demonstrate the strong dependence of these quantities on allotropic form and layer number. The study also reveals the strong interaction between helical chains of neighboring tellurium atoms, which cannot be solely explained by van der Waals interaction.
Article
Chemistry, Physical
Sweety Verma, Anshu Sharma, Sanjeev Maken
Summary: The measurement of density, viscosity, and ultrasonic speed was conducted to study the intermolecular interactions between p-chlorotoluene and alkanol. The derived excess properties and calculated partial molar volume provide insights into the extent and nature of the interactions. The results from theoretical models and correlations further illustrate the viscosity deviation and excess isentropic compressibility for these systems.
JOURNAL OF MOLECULAR LIQUIDS
(2023)
Article
Chemistry, Physical
Prakash Verma, Lee Huntington, Marc P. Coons, Yukio Kawashima, Takeshi Yamazaki, Arman Zaribafiyan
Summary: The MI-FNO framework introduces the method of increments and frozen natural orbitals to expedite the application of NISQ devices for quantum chemistry simulations, reducing occupied and virtual orbital spaces systematically. By utilizing algorithms like VQE, it can solve correlation energies for small molecules effectively and significantly reduce quantum resource requirements. This approach creates scalable examples of quantum chemistry problems suitable for assessing NISQ device progress.
JOURNAL OF CHEMICAL PHYSICS
(2021)
Article
Optics
K. Ayuel, Ahmed Zakaria, E. Longa
Summary: Density functional theory was applied to investigate the ground state properties and complex dielectric function of FeF2 compound. The complex expression of magnetic permeability was estimated using the formula of the magnetic permeability tensor. Densities of states and projected densities of states were determined to interpret optical transitions. Suitable expressions were derived and applied to account for the contributions of electric permittivity and magnetic permeability to optical properties. The absorption coefficient in the visible range was found to be attributed to transitions from the top of the valence band to 4s bands of Fe2+ cations in the conduction band. In the far-infrared region, FeF2 exhibited perfect reflection. The estimated optical properties were in good agreement with previous theoretical and experimental results in the literature.
JOURNAL OF THE OPTICAL SOCIETY OF AMERICA A-OPTICS IMAGE SCIENCE AND VISION
(2022)
Article
Chemistry, Multidisciplinary
Michal Novotny, Matus Dubecky, Frantisek Karlicky
Summary: This paper investigates the accuracy of different DFT-based computational approaches in calculating the equilibrium lattice constants and exfoliation energy of hexagonal boron nitride (h-BN). The results are compared with experiments and reference QMC calculations to evaluate the accuracy of these computational methods.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
Article
Chemistry, Multidisciplinary
Luigi Crisci, Federico Coppola, Alessio Petrone, Nadia Rega
Summary: The charge transfer dynamics in asymmetrically substituted indenotetracene molecules upon photo-excitation were investigated using real-time time-dependent density functional theory simulations. The study found that the electron-donating character of the substituents affects the overall electronic energy spacing and ultrafast charge transfer dynamics.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
Article
Chemistry, Multidisciplinary
Vasilii Korotenko, Hendrik Zipse
Summary: The stability of various radicals and molecules has been studied using different theoretical methods, and good correlations between theoretical calculations and experimental results have been found. The effects of hydrogen bonding interactions on the stability of oxygen-centered radicals have also been investigated.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
Article
Chemistry, Multidisciplinary
Oleg Egorov, Michael Rey, Dominika Viglaska, Andrei V. Nikitin
Summary: In this work, the rovibrational energy levels of four isotopologues of methylene were calculated using a new accurate ab initio potential energy surface. The accuracy of the calculations was improved by considering scalar relativistic effects, DBOC, and high-order electronic correlations. For the first time, all available experimental rovibrational transitions were reproduced with high accuracy, without any empirical corrections.
JOURNAL OF COMPUTATIONAL CHEMISTRY
(2024)
