scholarly journals The Resonant and Normal Auger Spectra of Ozone

Symmetry ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 516
Author(s):  
Simone Taioli ◽  
Stefano Simonucci
Keyword(s):  
Bound States ◽  
Point Group ◽  
Coulomb Repulsion ◽  
Theoretical Description ◽  
Incoming Wave ◽  
Decay Channels ◽  
Continuum States ◽  
Symmetric Molecule ◽  
Accurate Treatment ◽  
Auger Spectra

In this work, we outline a general method for calculating Auger spectra in molecules, which accounts for the underlying symmetry of the system. This theory starts from Fano’s formulation of the interaction between discrete and continuum states, and it generalizes this formalism to deal with the simultaneous presence of several intermediate quasi-bound states and several non-interacting decay channels. Our theoretical description is specifically tailored to resonant autoionization and Auger processes, and it explicitly includes the incoming wave boundary conditions for the continuum states and an accurate treatment of the Coulomb repulsion. This approach is implemented and applied to the calculation of the K−LL Auger and autoionization spectra of ozone, which is a C2v symmetric molecule, whose importance in our atmosphere to filter out radiation has been widely confirmed. We also show the effect that the molecular point group and, in particular, the localization of the core-hole in the oxygen atoms related by symmetry operations, has on the electronic structure of the Auger states and on the spectral lineshape by comparing our results with the experimental data.

scholarly journals The Resonant and Normal Auger Spectra of Ozone

2021 ◽  
Author(s):  
Simone Taioli ◽  
Stefano Simonucci
Keyword(s):  
Bound States ◽  
Point Group ◽  
Coulomb Repulsion ◽  
Theoretical Description ◽  
Incoming Wave ◽  
Decay Channels ◽  
Continuum States ◽  
Symmetric Molecule ◽  
Accurate Treatment ◽  
Auger Spectra

In this work we outline a general method for calculating Auger spectra in molecules, which accounts for the underlying symmetry of the system. This theory starts from Fano’s formulation of the interaction between discrete and continuum states and generalizes this formalism to deal with the simultaneous presence of several intermediate quasi-bound states and several non-interacting decay channels. Our theoretical description is specifically tailored to resonant autoionization and Auger processes, and includes explicitly the incoming wave boundary conditions for the continuum states and an accurate treatment of the Coulomb repulsion. This approach is implemented and applied to the calculation of the K−LL Auger and autoionization spectra of ozone, which is a C2v symmetric molecule, whose importance in our atmosphere to filter out radiation has been widely confirmed. We also show the effect that the molecular point group, and in particular the localization of the core-hole in the oxygen atoms related by symmetry operations, has on the electronic structure of the Auger states and on the spectral lineshape by comparing our results with experimental data.

Coupling of Bound States to Continuum States in Neutral Triatomic Hydrogen

2003 ◽  
pp. 275-288 ◽  
Author(s):  
H. Helm ◽  
U. Galster ◽  
I. Mistrík ◽  
U. Müller ◽  
R. Reichle
Keyword(s):  
Bound States ◽  
Continuum States

scholarly journals Compact Exotic Tetraquark Mesons in Large-Nc QCD

2018 ◽  
Vol 191 ◽  
pp. 04003
Author(s):  
Wolfgang Lucha ◽  
Dmitri Melikhov ◽  
Hagop Sazdjian
Keyword(s):  
Scattering Amplitudes ◽  
Quantum Chromodynamics ◽  
Internal Consistency ◽  
Selection Criteria ◽  
Bound States ◽  
Degrees Of Freedom ◽  
Decay Rates ◽  
Meson Decay ◽  
Decay Channels ◽  
Colour Singlet

We embark on systematic explorations of the behaviour of tetraquark mesons, i.e., colour-singlet bound states of two quarks and two antiquarks, in the (idealized) limit of a large number of colour degrees of freedom, Nc,; of quantum chromodynamics, QCD. Considering the scattering of two ordinary mesons into two ordinary mesons, we start off with formulating a set of selection criteria that should enable us to unambiguously single out precisely those contributions to all encountered scattering amplitudes that potentially will develop tetraquark poles. Assuming that tetraquark mesons do exist and, if so, emerge in the contributions compatible with our criteria at largest admissible order of Nc; we deduce, for the categories of tetraquarks that exhibit either four or only two different open quark flavours, that the decay rates of these tetraquark types are, at least, of order 1/N2c and that internal consistency requires all the members of the first species to exist pairwise, distinguishable by their favoured two-ordinary-meson decay channels.

Computational Investigation of the Interaction Between Hydrogen Atoms and an Intense Circularly Polarized Laser Field

2012 ◽  
Vol 11 (3) ◽  
pp. 756-774
Author(s):  
Lifeng Yang ◽  
Wang Xu ◽  
Qiren Zhang ◽  
Wen Luo ◽  
Qiangyan Pan ◽  
...  
Keyword(s):  
Experimental Data ◽  
Bound States ◽  
Strong Field ◽  
Computational Investigation ◽  
Hydrogen Atoms ◽  
Circularly Polarized ◽  
Continuum States ◽  
Above Threshold Ionization ◽  
Strong Field Physics ◽  
Nonperturbative Calculation

AbstractThe study of interactions between a high-power laser and atoms has been one of the fundamental and interesting topics in strong field physics for decades. Based on a nonperturbative model, ten years ago, we developed a set of programs to facilitate the study of interactions between a circularly polarized laser and atomic hydrogen. These programs included only contribution from the bound states of the hydrogen atom. However, as the laser intensity increases, contribution from continuum states to the excitation and ionization processes becomes larger and can no longer be neglected. Furthermore, because the original code is not able to add this contribution directly due to its many disadvantages, a major upgrade of the code is required before including the contribution from continuum states in future. In this paper, first we deduce some important formulas for contribution of continuum states and present modifications and tests for the upgraded code in detail. Second we show some comparisons among new results, old results from the original codes and the available experimental data. Overall the new result agrees with experimental data well. Last we present our calculation of above-threshold ionization (ATI) rate and compare it with a pertuba-tive calculation. The comparison shows that our nonperturbative calculation can also produce ATI peak suppression.

scholarly journals Symmetry of Bipolaron Bound States for Small Coulomb Repulsion

2012 ◽  
Vol 319 (2) ◽  
pp. 557-573 ◽  
Author(s):  
Rupert L. Frank ◽  
Elliott H. Lieb ◽  
Robert Seiringer
Keyword(s):  
Bound States ◽  
Coulomb Repulsion

scholarly journals Renormalised Perturbation Theory of Resonant Multiphoton Ionisation

1995 ◽  
Vol 48 (5) ◽  
pp. 835
Author(s):  
K Unnikrishnan
Keyword(s):  
Perturbation Theory ◽  
Cross Sections ◽  
Bound States ◽  
Resonance Region ◽  
Short Pulses ◽  
Total Cross Sections ◽  
Two Photon ◽  
Continuum States ◽  
The Mean ◽  
Good Agreement

Perturbation theory of multiphoton ionisation due to a classical electromagnetic field is modified to allow for intermediate resonances with bound states. Complex energies, generally associated with resonances, do not enter into this formalism. For a monochromatic field of frequency u, a constant ionisation rate can then be defined unambiguously and only such continuum states are excited which correspond to the absorption of energy in integral multiples of hu. As an application, differential and total cross sections for the two-photon ionisation of hydrogen, for frequencies below the n = 3 resonance region, are obtained in closed form. Existing data for generalised cross sections, calculated numerically using the complex coordinate method, are in good agreement with the present results. Finally, the mean fractional ionisation resulting from a pulse of finite duration is estimated on the basis of the associated power spectrum. For short pulses, the time dependence of ionisation exhibits a departure from that expected of a time-independent rate.

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