scholarly journals Revealing the Target Electronic Structure with Under-Threshold RABBIITT

Atoms ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 66
Author(s):  
Anatoli Kheifets
Keyword(s):  
Electronic Structure ◽  
Bound States ◽  
Energy Levels ◽  
Laser Frequency ◽  
Target Atom ◽  
Oscillator Strengths ◽  
Ionization Threshold ◽  
Discrete Energy ◽  
Two Photon

The process of reconstruction of attosecond beating by interference of two-photon transitions (RABBITT) reveals the target atom electronic structure when one of the transitions proceeds from below the ionization threshold. Such an under-threshold RABBITT resonates with the target bound states and thus maps faithfully the discrete energy levels and the corresponding oscillator strengths. We demonstrate this sensitivity by considering the Ne atom driven by the combination of the XUV and IR pulses at the fundmanetal laser frequency in the 800 and 1000 nm ranges.

scholarly journals Demystifying the spectral collapse in two-photon Rabi model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
C. F. Lo
Keyword(s):  
Energy Spectrum ◽  
Bound States ◽  
Energy Levels ◽  
Scattering Problem ◽  
Critical Coupling ◽  
Discrete Energy ◽  
Two Photon ◽  
Continuous Energy ◽  
Rabi Model ◽  
Continuous Energy Spectrum

Abstract We have investigated the eigenenergy spectrum of the two-photon Rabi model at the critical coupling, particularly the special feature “spectral collapse”, by means of an elementary quantum mechanics approach. The eigenenergy spectrum is found to consist of both a set of discrete energy levels and a continuous energy spectrum. Each of these eigenenergies has a two-fold degeneracy corresponding to the spin degree of freedom. The discrete eigenenergy spectrum has a one-to-one mapping with that of a particle in a “Lorentzian function” potential well, and the continuous energy spectrum can be derived from the scattering problem associated with a potential barrier. The number of bound states available at the critical coupling is determined by the energy difference between the two atomic levels so that the extent of the “spectral collapse” can be monitored in a straightforward manner.

scholarly journals Spectral collapse in anisotropic two-photon Rabi model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
C. F. Lo
Keyword(s):  
Bound States ◽  
Energy Levels ◽  
Energy Difference ◽  
Bound State ◽  
Discrete Energy ◽  
Radiation Mode ◽  
Two Photon ◽  
Rabi Model ◽  
Matter Interaction ◽  
Light Matter Interaction

AbstractIn this communication, based upon a squeezed-state trial wave function, we have performed a simple variational study of the spectral collapse in the anisotropic two-photon Rabi model. Our analysis indicates that the light-matter interaction and the spin-flipping (together with the anisotropy) effectively constitute two competing impacts upon the radiation mode. Whilst the former tries to decrease the radiation mode frequency, the latter may counteract or reinforce it. The light-matter interaction appears to dominate the frequency modulation as its coupling strengths go beyond the critical values, leading to the emergence of the spectral collapse. However, at the critical couplings the dominance of the light-matter interaction is not complete, and incomplete spectral collapse appears. Accordingly, at the critical couplings the eigenenergy spectrum comprises both a set of discrete energy levels and a continuous energy spectrum. The discrete eigenenergy spectrum can be derived via a simple one-to-one mapping to the bound state problem of a particle of variable effective mass in a finite potential well, and the number of bound states available is determined by the energy difference between the two atomic levels. Each of these eigenenergies has a twofold degeneracy corresponding to the spin degree of freedom.

Small is different

2021 ◽  
pp. 81-93
Author(s):  
Adrian P Sutton
Keyword(s):  
Crystal Structure ◽  
Electronic Structure ◽  
Catalytic Activity ◽  
Giant Magnetoresistance ◽  
Energy Levels ◽  
Exclusion Principle ◽  
Thermodynamic Quantities ◽  
Discrete Energy ◽  
Size Dependent ◽  
The World

As the size of a material decreases to the nanoscale its properties become size-dependent. This is the world of nanoscience and nanotechnology. At the nanoscale the crystal structure may change and thermodynamic quantities such as the melting point also change. Changes in the catalytic activity and colour of nanoparticles suspended in a liquid indicate changes to the electronic structure. Quantum dots have discrete energy levels that can be modelled with the particle-in-a-box model. Excitons may be created in them using optical illumination, and their decay leads to fluorescence with distinct colours. The classical and quantum origins of magnetism are discussed. The origin of magnetoresistance in a ferromagnet is described and related to the exclusion principle. The origin of the giant magnetoresistance effect and its exploitation in nanotechnology is outlined.

scholarly journals Discrete spectrum of many body Schrödinger operators with non-constant magnetic fields II

1997 ◽  
Vol 145 ◽  
pp. 69-98
Author(s):  
Tetsuya Hattori
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Discrete Spectrum ◽  
Bound States ◽  
Atomic System ◽  
Energy Levels ◽  
Schrödinger Operators ◽  
Schrodinger Operators ◽  
Many Body ◽  
Discrete Energy

This paper is continuation from [10], in which we studied the discrete spectrum of atomic Hamiltonians with non-constant magnetic fields and, more precisely, we showed that any atomic system has only finitely many bound states, corresponding to the discrete energy levels, in a suitable magnetic field. In this paper we show another phenomenon in non-constant magnetic fields that any atomic system has infinitely many bound states in a suitable magnetic field.

Bonding and Spectra of Molecules and Solids

2021 ◽  
pp. 147-219
Author(s):  
Kannan M. Krishnan
Keyword(s):  
Electronic Structure ◽  
Nearest Neighbor ◽  
Transition Probabilities ◽  
Single Photon ◽  
Energy Levels ◽  
Many Body ◽  
X Ray ◽  
Two Photon ◽  
Curing Of Polymer ◽  
X Ray Absorption

The electronic structure of molecules includes electronic (2-10 eV, UV-Vis absorption), vibrational (10-2 - 2 eV, infrared spectroscopy & Raman scattering), and rotational (10–5 – 10–3 eV, microwave spectroscopy) energy levels that are probed by appropriate spectroscopy methods. Light, incident on a molecule or molecular solid, is either absorbed (IR, single photon, non-zero derivative of dipole moment), or elastically (Rayleigh) or inelastically (Raman, two-photon, non-zero derivative of the polarizability) scattered. Fourier transform infrared (FTIR) spectroscopy finds much use in materials characterization, including in studying the curing of polymer composites now incorporated in aircraft structures. When atoms form solids their electronic structure, particularly the energy levels of the outer electrons involved in the bonding, are significantly altered. Both occupied and unoccupied levels in solids are probed. Photoemission spectroscopy (PES) with X-rays (XPS) or ultraviolet light (UPS) incidence, and inverse PES probe occupied and unoccupied energy levels of surfaces, respectively. X-ray absorption spectroscopy (XAS) complements XPS, and probes unoccupied energy levels of solids. X-ray absorption near-edge structure (XANES) provides information on the final density of unoccupied states, the transition probabilities, and many body effects. Extended X-ray absorption fine structure (EXAFS) provides element-specific nearest neighbor distances and their coordination number.

DETERMINATION OF LINEAR-CHAIN MULTIPLE BOUND STATE RESONANCES IN REFLECTION HIGH-ENERGY ELECTRON DIFFRACTION

1994 ◽  
Vol 01 (02n03) ◽  
pp. 261-271 ◽  
Author(s):  
T.C. ZHAO ◽  
S.Y. TONG ◽  
A. IGNATIEV
Keyword(s):  
Electron Diffraction ◽  
Bound States ◽  
Energy Levels ◽  
Linear Chain ◽  
Bound State ◽  
High Energy ◽  
Dynamical Theory ◽  
Energy Electron ◽  
High Energy Electron ◽  
Discrete Energy

Using the R-matrix dynamical theory of Reflection High-Energy Electron Diffraction (RHEED), we analyze the intensity anomalies commonly observed in RHEED rocking curves. Results for Ag(001) and Pt(111) show that the anomalies are associated with the trapping of particular components of the electron wave field inside the crystal by linear chain potential parallel to the surface. These pseudobound states correspond to minima in the total elastic flux of an ultrathin film (≤10 monolayer) and maxima in the inelastic flux. The discrete energy levels of the bound states in Ag(001) and Pt(111) are determined for the first time and the effect of such bound states on the rocking curves is discussed.

scholarly journals SPECTRAL AND TRANSPORT PROPERTIES OF ONE-DIMENSIONAL NANORING SUPERLATTICE

2013 ◽  
Vol 27 (20) ◽  
pp. 1350103 ◽  
Author(s):  
M. A. PYATAEV ◽  
M. A. KOKOREVA
Keyword(s):  
Magnetic Field ◽  
Energy Spectrum ◽  
Electron Energy ◽  
Spectral Properties ◽  
Bound States ◽  
Energy Levels ◽  
Electron Energy Spectrum ◽  
Discrete Energy ◽  
One Dimensional ◽  
System Parameters

Spectral properties of periodic one-dimensional array of nanorings in a magnetic field are investigated. Two types of the superlattice are considered. In the first one, rings are connected by short one-dimensional wires while in the second one rings have immediate contacts between each other. The dependence of the electron energy on the quasimomentum is obtained from the Schrödinger equation for the Bloch wavefunction. We have found an interesting feature of the system, namely, presence of discrete energy levels in the spectrum. The levels can be located in the gaps or in the bands depending on parameters of the system. The levels correspond to bound states and electrons occupying these levels are located on individual rings or couples of neighboring rings and do not contribute to the charge transport. The wavefunction for the bound states corresponding to the discrete levels is obtained. Modification of electron energy spectrum with variation of system parameters is discussed.

Systematic calculations of energy levels and transitions rates in Mo XXVIII

2020 ◽  
Vol 75 (8) ◽  
pp. 739-747
Author(s):  
Feng Hu ◽  
Yan Sun ◽  
Maofei Mei
Keyword(s):  
Energy Levels ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Data Sets ◽  
Electron Systems ◽  
Excitation Energies ◽  
Experimental Values ◽  
Qed Effects ◽  
Hyperfine Structures ◽  
Good Agreement

AbstractComplete and consistent atomic data, including excitation energies, lifetimes, wavelengths, hyperfine structures, Landé gJ-factors and E1, E2, M1, and M2 line strengths, oscillator strengths, transitions rates are reported for the low-lying 41 levels of Mo XXVIII, belonging to the n = 3 states (1s22s22p6)3s23p3, 3s3p4, and 3s23p23d. High-accuracy calculations have been performed as benchmarks in the request for accurate treatments of relativity, electron correlation, and quantum electrodynamic (QED) effects in multi-valence-electron systems. Comparisons are made between the present two data sets, as well as with the experimental results and the experimentally compiled energy values of the National Institute for Standards and Technology wherever available. The calculated values including core-valence correction are found to be in a good agreement with other theoretical and experimental values. The present results are accurate enough for identification and deblending of emission lines involving the n = 3 levels, and are also useful for modeling and diagnosing plasmas.

Energy Levels of Core-Excited States and Atomic Oscillator Strengths for Boron and Boron-like Ions (abstract)

2009 ◽  
Author(s):  
Magda A. Rahim ◽  
Beverly Karplus Hartline ◽  
Renee K. Horton ◽  
Catherine M. Kaicher
Keyword(s):  
Excited States ◽  
Energy Levels ◽  
Oscillator Strengths
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