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In a recent letter [Phys. Rev. Lett. 131, 216401] we presented the multichannel Dyson equation (MCDE) in which two or more many-body Green's functions are coupled. In this work we will give further details of the MCDE approach. In particular we will discuss: 1) the derivation of the MCDE and the definition of the space in which it is to be solved; 2) the rationale of the approximation to the multichannel self-energy; 3) a diagrammatic analysis of the MCDE; 4) the recasting of the MCDE on an eigenvalue problem with an effective Hamiltonian that can be solved using standard numerical techniques. This work mainly focuses on the coupling between the one-body Green's function and the three-body Green's function to describe photoemission spectra, but the MCDE method can be generalized to the coupling of other many-body Green's functions and to other spectroscopies.

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Galvinoxyl, as one of the most extensively studied organic stable free radicals, exhibits a notable phase transition from a high-temperature (HT) phase with a ferromagnetic (FM) intermolecular interaction to a low-temperature (LT) phase with an antiferromagnetic (AFM) coupling at 85 K. Despite significant research efforts, the crystal structure of the AFM LT phase has remained elusive. This study successfully elucidates the crystal structure of the LT phase, which belongs to the P[1 with combining macron] space group. The crystal structure of the LT phase is found to consist of a distorted dimer, wherein the distortion arises from the formation of short intermolecular distances between anti-node carbons in the singly-occupied molecular orbital (SOMO). Starting from the structure of the LT phase, wave function calculations show that the AFM coupling 2J/kB varies significantly from −1069 K to −54 K due to a parallel shift of the molecular planes within the dimer.

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We performed several types of ab initio calculations, from Hartree-Fock to Complete-Active-Space second-order perturbation theory and Coupled Cluster, on compact clusters of stoichiometry XY, where X and Y are atoms belonging to the second row of the periodic table. More precisely, we considered the “cubic” structures of three isoelectronic groups, having a total of 48, 52, and 56-electrons, respectively. Notice that the highly symmetric cubic clusters of type X are characterized by an symmetry group, while the XY structures, with XY, have at most a symmetry. Binding energies and wave function analysis of these clusters have been performed, in order to investigate the nature, and the electron delocalization of these systems and establish a comparison between them. To this purpose, we also computed the Total-Position Spread tensor for each structure, a quantity which is related to the multi-reference nature of a system wave function.

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Methyl-p-benzoquinone (MpBQ, CH3C6H3(═O)2) is a prototypical molecule in the study of quinones, which are compounds of relevance in biology and several redox reactions. Understanding the electron attachment properties of MpBQ and its ability to form anions is crucial in elucidating its role in these reactions. In this study, we investigate electron attachment to MpBQ employing a crossed electron-molecular beam experiment in the electron energy range of approximately 0 to 12 eV, as well as theoretical approaches using quantum chemical and electron scattering calculations. Six anionic species were identified: C7H6O2–, C7H5O2–, C6H5O–, C4HO–, C2H2–, and O–. The parent anion is formed most efficiently, with large cross sections, through two resonances at electron energies between 1 and 2 eV. Potential reaction pathways for all negative ions observed are explored, and the experimental appearance energies are compared with calculated thermochemical thresholds. Although exhibiting similar electron attachment properties to pBQ, MpBQ’s additional methyl group introduces entirely new dissociative reactions, while quenching others, underscoring its distinctive chemical behavior.

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Sujets

CP violation Quantum Chemistry Wave functions Carbon Nanotubes Relativistic corrections Atrazine-cations complexes Ground states Molecular properties Range separation Polarizabilities Atomic charges chemical concepts maximum probability domain population 3115ae Time reversal violation 3115aj 3115am Anharmonic oscillator Théorie des perturbations Corrélation électronique Adiabatic connection Dipole Argile Ab initio calculation 3115vn Valence bond Line formation AB-INITIO CALCULATION Relativistic quantum mechanics Perturbation theory Aimantation Spin-orbit interactions Atomic charges Diffusion Monte Carlo BIOMOLECULAR HOMOCHIRALITY Atomic data X-ray spectroscopy Abiotic degradation Excited states Electron correlation Electron electric moment BENZENE MOLECULE Dirac equation Green's function A posteriori Localization Configuration interactions 3470+e Approximation GW Path integral 3115bw Coupled cluster Argon Coupled cluster calculations Chemical concepts ALGORITHM Atom Parallel speedup A priori Localization Atomic processes Petascale New physics Atrazine 3115ag Quantum chemistry Molecular descriptors Density functional theory Xenon QSAR Electron electric dipole moment Time-dependent density-functional theory Acrolein Auto-énergie Quantum Monte Carlo Diatomic molecules Hyperfine structure Analytic gradient 3115vj Rydberg states Atoms Single-core optimization Chimie quantique États excités Atomic and molecular structure and dynamics Dispersion coefficients Numerical calculations Biodegradation AB-INITIO Mécanique quantique relativiste Pesticides Metabolites Clustering Molecular modeling Environmental fate Partial least squares Azide Anion Pesticide Atomic and molecular collisions Fonction de Green Relativistic quantum chemistry AROMATIC-MOLECULES 3315Fm Anderson mechanism CIPSI Ion Parity violation Large systems Configuration Interaction

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252

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273