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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

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

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