Search results for "Wave function"
showing 10 items of 395 documents
Circular dichroism in X-ray photoemission from Pd(111) and CO/Pd(111)
1995
It is shown experimentally that in the soft X-ray region a large circular dichroism in the photoelectron angular distribution (CDAD) exists for both valence orbitals and core levels of CO molecules adsorbed on Pd(111). From theoretical consideration it follows that in the case of a spherically symmetric ground state wave function, like the 1σ and 2σ orbitals of CO, CDAD appears due to the lack of spherical symmetry in the final state. For carbonK-shell experimental results are compared to model calculations. Investigations at the Pd core levels proved that CDAD does also arise in X-ray photo-emission from non-magnetic crystals.
Variational Bethe ansatz approach for dipolar one-dimensional bosons
2020
We propose a variational approximation to the ground state energy of a one-dimensional gas of interacting bosons on the continuum based on the Bethe Ansatz ground state wavefunction of the Lieb-Liniger model. We apply our variational approximation to a gas of dipolar bosons in the single mode approximation and obtain its ground state energy per unit length. This allows for the calculation of the Tomonaga-Luttinger exponent as a function of density and the determination of the structure factor at small momenta. Moreover, in the case of attractive dipolar interaction, an instability is predicted at a critical density, which could be accessed in lanthanide atoms.
Polarization angle dependence of the breathing modes in confined one-dimensional dipolar bosons
2021
Probing the radial collective oscillation of a trapped quantum system is an accurate experimental tool to investigate interactions and dimensionality effects. We consider a fully polarized quasi-one dimensional dipolar quantum gas of bosonic dysprosium atoms in a parabolic trap at zero temperature. We model the dipolar gas with an effective quasi-one dimensional Hamiltonian in the single-mode approximation, and derive the equation of state using a variational approximation based on the Lieb-Liniger gas Bethe Ansatz wavefunction or perturbation theory. We calculate the breathing mode frequencies while varying polarization angles by a sum-rule approach, and find them in good agreement with re…
Entangled photons through thick scattering media: experiments and comparison with simulations of the biphoton wave function
2021
International audience; We report experimentally and numerically quantum correlations imaging through thick random media. We demonstrated that spatial correlations between twin photon are still detected but no in form of two-photon speckle-like patterns.
Excitons in few-layer hexagonal boron nitride: Davydov splitting and surface localization
2018
Hexagonal boron nitride (hBN) has been attracting great attention because of its strong excitonic effects. Taking into account few-layer systems, we investigate theoretically the effects of the number of layers on quasiparticle energies, absorption spectra, and excitonic states, placing particular focus on the Davydov splitting of the lowest bound excitons. We describe how the inter-layer interaction as well as the variation in electronic screening as a function of layer number $N$ affects the electronic and optical properties. Using both \textit{ab initio} simulations and a tight-binding model for an effective Hamiltonian describing the excitons, we characterize in detail the symmetry of t…
Airy-function approach to binary black hole merger waveforms: The fold-caustic diffraction model
2022
From numerical simulations of the Einstein equations, and also from gravitational wave observations, the gravitational wave signal from a binary black hole merger is seen to be simple and to possess certain universal features. The simplicity is somewhat surprising given that non-linearities of general relativity are thought to play an important role at the merger. The universal features include an increasing amplitude as we approach the merger, where transition from an oscillatory to a damped regime occurs in a pattern apparently oblivious to the initial conditions. We propose an Airy-function pattern to model the binary black hole (BBH) merger waveform, focusing on accounting for its simpl…
Localized states in wide-gap oxide glasses
1997
Localized states manifest themselves by light absorption at the optical gap of a glass and by luminescence excited there with Stoke's shift. They are created by the minority structural motifs of one or many structural modifications in which a material can exist, and which can provide electronic states absorption at the optical gap. Their wavefunctions overlapping determine the luminescence intensity dependence on the temperature [I(T)on the order of magnitude exp(- T/T 0 )] and power law (t -1 ) of luminescence decay kinetics, which include intra-center processes due to triplet-singlet transitions and recombination processes due to a tunnel and overbarrier transitions, as well as a fast com…
ChemInform Abstract: A Theoretical Determination of the Dissociation Energy of the Nitric Oxide Dimer.
2010
Multi-reference CI methods have been applied to determine the dissociation energy and structure of thecis-N2O2 molecule. The convergence of the theoretical result has been checked with respect to a systematic expansion of the one-electron basis set and the multi-reference CI wave function. The best calculated value, 13.8 kJ/mol, is in agreement with the experimental value, 12.2 kJ/mol. It has been obtained with an extended ANO-type basis set [6s5p3d2f], including the effect of the basis set superposition error (BSSE) in the geometry optimization, and additional effects, such as the electron correlation of core electrons and relativistic corrections, using the average coupled pair functional…
Population analysis of pair densities. A study on cyclic systems
2000
Abstract Pair population analysis seems a reliable method for evaluating atomic valency states and bond orders from the MO wavefunction of molecular systems. A test on some cyclic organic systems was performed. The results confirm the capability of the method to provide a correct description of the molecules in terms of simple VB approach.
The gallium anomaly revisited
2019
The gallium anomaly, i.e. the missing electron-neutrino flux from $^{37}$Ar and $^{51}$Cr electron-capture decays as measured by the GALLEX and SAGE solar-neutrino detectors, has been among us already for about two decades. We present here a new estimate of the significance of this anomaly based on cross-section calculations using nuclear shell-model wave functions obtained by exploiting recently developed two-nucleon interactions. The gallium anomaly of the GALLEX and SAGE experiments is found to be smaller than that obtained in previous evaluations, decreasing the significance from 3.0σ to 2.3σ. This result is compatible with the recent indication in favor of short-baseline ν¯e disappeara…