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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

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

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