The coupling of matter to the quantized electromagnetic field a plasmonic or optical cavity can be harnessed modify and control chemical physical properties molecules. In cavities, term known as dipole self-energy (DSE) appears in Hamiltonian ensure gauge invariance. aim this work is twofold. First, we introduce method, which has its own merits complements existing methods, compute DSE. Second, study impact DSE on cavity-induced nonadiabatic dynamics realistic system. For that purpose,...

Abstract Positron binding to molecules is key extremely enhanced positron annihilation and positron-based molecular spectroscopy 1 . Although energies have been measured for about 90 polyatomic 1–6 , an accurate ab initio theoretical description of positron–molecule has remained elusive. Of the studied experimentally, calculations exist only six; these agree with experiments on polar at best 25 per cent accuracy fail predict in nonpolar molecules. The challenge stems from need accurately...

Positron binding energies in halogenated hydrocarbons are calculated using many-body theory. For chlorinated molecules, including planars for which the interaction is highly anisotropic, very good to excellent agreement with experiment and recent density-functional-theory-based model-potential calculations found. Predictions fluorinated brominated molecules presented. The comparative effect of fluorination, chlorination, bromination elucidated by identifying trends within molecular families...

The recently developed ab initio many-body theory of positron molecule binding [22J. Hofierka et al., Many-body to polyatomic molecules, Nature (London) 606, 688 (2022)NATUAS0028-083610.1038/s41586-022-04703-3] is combined with the shifted pseudostates method [A. R. Swann and G. F. Gribakin, Model-potential calculations binding, scattering, annihilation for atoms small molecules using a Gaussian basis, Phys. Rev. A 101, 022702 (2020)PLRAAN2469-992610.1103/PhysRevA.101.022702] calculate...

The energetic stability of positron–dianion systems [A−; e+; A−] is studied via many-body theory, where A− includes H−, F−, Cl−, and the molecular anions (CN)− (NCO)−. Specifically, energy system as a function ionic separation determined by solving Dyson equation for positron in field two using positron–anion self-energy constructed Hofierka et al. [Nature 606, 688 (2022)] that accounts correlations, including polarization, screening, virtual-positronium formation. Calculations are performed...

Doppler-broadened $\gamma$-ray spectra for positron annihilation on molecules are calculated using many-body theory. By employing Gaussian bases the electron and wavefunctions, a computable expression that involves four-centre integral over two-annihilation-photon momenta is derived $\gamma$ in independent particle model approximation to vertex, implemented open-source {\tt EXCITON+} code. The influence of electron-positron correlations examined through \textit{ab initio} treatment...

Abstract Positron bound state properties in hydrogen cyanide are studied via many-body theory calculations that account for strong positron-electron correlations including positron-induced polarization, screening of the electron–positron Coulomb interaction, virtual-positronium formation and positron–hole repulsion. Specifically, Dyson equation is solved using a Gaussian basis, with positron self-energy field molecule calculated Bethe–Salpeter equations two-particle particle–hole...

Energy transfer processes are ubiquitous in nature and intensely investigated. The investigations concentrate on the of small to intermediate sized energies. Here, we pose question whether large energies, where relativistic effects play a central role, can be efficient. At process leads ionization environment, i.e., it is interatomic (or intermolecular) Coulombic decay (ICD) process. To that end, derive asymptotic expressions for ICD amplitude by employing Dirac–Breit Hamiltonian expanding...

The authors present experimental data for annihilation spectra and binding energies positron interactions with several aromatic heterocyclic ring molecules. results are compared the predictions of an $a\phantom{\rule{0}{0ex}}b$ $i\phantom{\rule{0}{0ex}}n\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}t\phantom{\rule{0}{0ex}}i\phantom{\rule{0}{0ex}}o$ theory excellent agreement.

Scattering phase shifts and annihilation rates for low-energy positrons interacting with noble gas atoms are calculated ab initio using many-body theory implemented in the Gaussian-orbital code EXCITON+. Specifically, we construct positron–atom correlation potential (self-energy) as sum of three classes infinite series describing screened polarization, virtual positronium formation, positron-hole repulsion found via solution Bethe–Salpeter equations two-particle propagators. The...

In interatomic Coulombic decay (ICD) an excited neutral atom or ion transfers its excess energy to ionize a neighboring atom. If the excitation ionization involves valence electrons, process is efficient (typically in femtosecond regime), becomes more neighbors are present, and often dominates all other relaxation processes. The situation changes when considering of core electrons. For light atoms, core-level ICD inferior Auger decay, but still relevant pathway. heavy atoms enormous by...

We calculate binding energies of four molecular solids using the Hartree-Fock (HF) and second-order Møller-Plesset perturbation theory (MP2).We obtain within many-body expansion (MBE) as well periodic boundary conditions (PBC) to compare both approaches.The systems we study are methane, carbon dioxide, ammonia, methanol.We use tight convergence settings with a high precision, estimate uncertainties be only few tenths percent.We discuss several issues that affect quality results which need...

The coupling of matter to the quantized electromagnetic field a plasmonic or optical cavity can be harnessed modify and control chemical physical properties molecules. In cavities, term known as dipole self-energy (DSE) appears in Hamiltonian assure gauge invariance. aim this work is twofold. First, we introduce method, which has its own merits complements existing methods, compute DSE. Second, study impact DSE on cavity-induced nonadiabatic dynamics realistic system. For that purpose,...

Positron binding energies in the negative ions H$^-$, F$^-$, Cl$^-$ and Br$^-$, closed-shell atoms Be, Mg, Zn Ca, are calculated via a many-body theory approach developed by authors [J.~Hofierka \emph{et al.} Nature~{\bf 608}, 688-693 (2022)]. Specifically, Dyson equation is solved using Gaussian basis, with positron self energy constructed from three infinite classes of diagrams that account for strong positron-atom correlations characterise system including positron-induced polarization...

Annihilation spectra are presented for aromatic and heterocyclic ring molecules resolved as a function of incident positron energy using trap-based beam. Comparisons with the vibrational mode yield positron-molecule binding energies. Good to excellent agreement is found between measured energies predictions an \textit{ab initio} many-body theory that takes proper account electron-positron correlations including virtual-positronium formation. The calculations elucidate competition permanent...

Positrons bind to molecules leading vibrational excitation and spectacularly enhanced annihilation. Whilst positron binding energies have been measured via resonant annihilation spectra for $\sim$90 in the past two decades, an accurate \emph{ab initio} theoretical description has remained elusive. Of studied experimentally, calculations exist only 6, these, standard quantum chemistry approaches proved severely deficient, agreeing with experiment at best 25% accuracy polar molecules, failing...