The direct random-phase approximation (dRPA) is used to calculate and compare atomization energies for the HEAT set and ten selected molecules of the G2-1 set using both plane waves and Gaussian-type orbitals. We describe detailed procedures to obtain highly accurate and well converged results for the projector augmented-wave method as implemented in the Vienna Ab initio Simulation Package as well as the explicitly correlated dRPA-F12 method as implemented in the TURBOMOLE package. The two approaches agree within chemical accuracy (1 kcal/mol) for the atomization energies of all considered molecules, both for the exact exchange as well as for the RPA. The root mean-square deviation is 0.41 kcal/mol for the exact exchange (evaluated using density functional theory orbitals) and 0.33 kcal/mol for exact exchange plus correlation from the RPA.
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http://dx.doi.org/10.1063/5.0124019 | DOI Listing |
Plants (Basel)
January 2025
Department of Agrarian and Exact, Universidade Estadual da Paraíba, Catolé do Rocha 58884-000, PB, Brazil.
Freshwater depletion becomes a significant challenge as the population grows and food demand rises. We evaluated the responses of lettuce cultivars () under saline stress in photosynthetic responses, production, and ion homeostasis. We used a randomized block design in a 3 × 5 factorial scheme with five replications-the first factor: three cultivars of curly lettuce: SVR 2005, Simpson, and Grand Rapids.
View Article and Find Full Text PDFAnimals (Basel)
January 2025
Departament of Agricultural Engineering, Universidade Federal de Viçosa, Viçosa 36570-900, Brazil.
Heat stress in animals affects productivity, health, and reproduction, with particularly pronounced effects in dairy cows. Identifying heat stress requires understanding both physiological and environmental indicators, such as increased heart rate, respiratory rate, and rectal temperature, which reflect the animal's thermal condition within its environment. Thermoregulation in cows involves behavioral and physiological adjustments to maintain homeothermy, aiming to stabilize their internal thermal state.
View Article and Find Full Text PDFSci Rep
January 2025
Applied Optics Laboratory, Institute of Optics and Precision Mechanics, University Setif 1, Setif, 19000, Algeria.
This prediction evaluates the different physical characteristics of magnetic materials XFeO (X = Mg, Ca and Sr) by using density functional theory (DFT). The generalized gradient approximation (GGA) approach is chosen to define the exchange and correlation potential. The structural study of the compounds XFeO (X = Mg, Ca and Sr) shows that the ferromagnetic phase is the more stable ground state, where all the parameters of the network are given at equilibrium.
View Article and Find Full Text PDFJ Phys Chem A
January 2025
Laboratoire de Chimie Quantique, Institut de Chimie, CNRS/Université de Strasbourg, 4 rue Blaise Pascal, 67000 Strasbourg, France.
A Kohn-Sham (KS) density-functional energy expression is derived for any (ground or excited) state within a given many-electron ensemble along with the stationarity condition it fulfills with respect to the ensemble density, thus giving access to both physical energy levels and individual-state densities, in principle exactly. We also provide working equations for the evaluation of the latter from the true static ensemble density-density linear response function. Unlike in Gould's recent ensemble potential functional approach to excited states [arXiv:2404.
View Article and Find Full Text PDFJ Chem Theory Comput
January 2025
Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K.
Density functional approximations can reduce the spin symmetry breaking observed for self-consistent field (SCF) solutions compared to Hartree-Fock theory, but the amount of exact Hartree-Fock (HF) exchange appears to be a key determinant in broken symmetry. To elucidate the precise role of exact exchange, we investigate the energy landscape of unrestricted Hartree-Fock and Kohn-Sham density functional theory for benzene and square cyclobutadiene, which provide paradigmatic examples of closed-shell and open-shell electronic structures, respectively. We find that increasing the amount of exact exchange leads to more local SCF minima, which can be characterized as combinatorial arrangements of unpaired electrons in the carbon π system.
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