Related papers: Positron annihilation and binding in aromatic and …
This paper studies the gamma-ray spectra of positron annihilation processes in a series of molecules. The results show that the average valence electron energy of the molecules has a linear correlation with the full width at half maximum…
We investigate the phase separation mechanism of bosonic binary mixtures in spatially-fragmented traps, evidencing the emergence of phases featuring a different degree of mixing. The analysis is initially carried out by means of a…
We present a first-principles-based multiscale simulation framework for quantitative predictions of the high-energy part of the Ultraviolet Photoelectron Spectroscopy (UPS) spectra of amorphous molecular solids. The approach combines a…
A major obstacle for computing optical spectra of solids is the lack of reliable approximations for capturing excitonic effects within time-dependent density-functional theory. We show that the trustful prediction of strongly bound…
The general properties of antiproton-proton annihilation at rest are presented, with special focus on the two-meson final states. The data exhibit remarkable dynamical selection rules : some allowed annihilation modes are suppressed by one…
The absorption and emission spectra of most luminescent, pi-conjugated, organic molecules are the mirror image of each other. In some cases, however, this symmetry is severely broken. In the present work, the asymmetry between the…
An impurity interacting with an ultracold Fermi gas can form either a polaron state or a dressed molecular state in which the impurity forms a bound state with one gas particle. This molecular state features rich physics, including a…
We analyse the entanglement tradeoff between particle and anti-particle modes of a charged bosonic field between inertial and uniformly accelerated observers. In contrast with previous results for fermionic fields, we find that the…
Preliminary results are presented from a new positron beam system currently under development at the University of Texas at Arlington for the coincident energy measurement of Doppler-shifted annihilation quanta and positron-induced Auger…
A thorough critical analysis of the theoretical relationships between the bond-angle dispersion in a-Si and the width of the transverse optical (TO) Raman peak is presented. It is shown that the discrepancies between them are drastically…
Positronium annihilation amplitudes that are computed by assuming a factorization approximation with on-shell intermediate leptons, do not exhibit good analytical behavior. We propose an ansatz which allows to include binding energy…
We perform a comparative beyond mean-field study of black and grey solitonic excitations in a finite ensemble of ultracold bosons confined to a one-dimensional box. An optimized density-engineering potential is developed and employed…
We present a variational many-body wave function for repelling bosons in rotating traps, focusing on rotational frequencies that do not lead to restriction to the lowest Landau level. This wave function incorporates correlations beyond the…
We present a theoretical approach based on density functional theory supplemented by a microscopic multi-phonon model which is applied for investigations of pygmy resonances and other excitations of different multipolarities in stable and…
An effective theory of the excited states of positronium is derived and some of its consequences are explored. At large physical separation, the binding of the electron and positron is assumed to be described completely by QED, whereas all…
Different ways of dealing with one-dimensional (1D) spectra, measured e.g. in the Compton scattering or angular correlation of positron annihilation radiation (ACAR) experiments are presented. On the example of divalent hexagonal close…
The low-energy scattering properties of two aligned identical bosonic and identical fermionic dipoles are analyzed. Generalized scattering lengths are determined as functions of the dipole moment and the scattering energy. Near resonance,…
The annihilation channel is implemented into the front form calculations of the positronium spectrum presented in a previous publication. The effective Hamiltonian is calculated analytically. Its eigensolutions are obtained numerically. A…
Accurate rovibrational molecular models are employed to gain insight in high-resolution into the collective effects and intermolecular processes arising when molecules in the gas phase are interacting with a resonant infrared (IR) radiation…
The electron and positron cosmic rays puzzle has triggered a revolution in the field of astroparticle physics. Many hypotheses have been proposed to explain the unexpected rise of the positron fraction, observed by HEAT and PAMELA…