Mechanism for decay and spontaneous radiative decay constants of the lowest‐lying attractive excited states of Ne2, Ar2, and Kr2

1974 ◽  
Vol 61 (11) ◽  
pp. 4740-4746 ◽  
Author(s):  
T. Oka ◽  
K. V. S. Rama Rao ◽  
J. L. Redpath ◽  
R. F. Firestone
Keyword(s):  
Excited States ◽  
Radiative Decay ◽  
Decay Constants

scholarly journals Radiative Decay Widths of Ground and Excited States of Vector Charmonium and Bottomonium

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Hluf Negash ◽  
Shashank Bhatnagar
Keyword(s):  
Mass Spectrum ◽  
Excited States ◽  
Mass Spectra ◽  
Reasonable Agreement ◽  
Radiative Decay ◽  
Decay Constants ◽  
Two Photon ◽  
Quantum Numbers ◽  
Decay Widths ◽  
Input Parameters

We study the radiative decay widths of vector quarkonia for the process of J/ψ(nS)→ηc(nS)γ and Υ(nS)→ηb(nS)γ (for principal quantum numbers n=1,2,3) in the framework of Bethe-Salpeter equation under the covariant instantaneous ansatz using a 4×4 form of BSE. The parameters of the framework were determined by a fit to the mass spectrum of ground states of pseudoscalar and vector quarkonia, such as ηc, ηb, J/ψ, and Υ. These input parameters so fixed were found to give good agreements with data on mass spectra of ground and excited states of pseudoscalar and vector quarkonia, leptonic decay constants of pseudoscalar and vector quarkonia, two-photon decays, and two-gluon decays of pseudoscalar quarkonia in our recent paper. With these input parameters so fixed, the radiative decay widths of ground (1S) and excited (2S,3S) states of heavy vector quarkonia (J/Ψ and Υ) are calculated and found to be in reasonable agreement with data.

Restriction of Access to Dark State: A New Mechanistic Model for Heteroatom-Containing AIE Systems

2019 ◽  
Author(s):  
Yujie Tu ◽  
Junkai Liu ◽  
Haoke Zhang ◽  
Qian Peng ◽  
Jacky W. Y. Lam ◽  
...  
Keyword(s):  
Excited States ◽  
Radiative Decay ◽  
Molecular Design ◽  
Mechanistic Model ◽  
Zinc Ion ◽  
Easy Access ◽  
Triplet States ◽  
Dark State ◽  
Ion Probe ◽  
Π State

Aggregation-induced emission (AIE) is an unusual photophysical phenomenon and provides an effective and advantageous strategy for the design of highly emissive materials in versatile applications such as sensing, imaging, and theragnosis. "Restriction of intramolecular motion" is the well-recognized working mechanism of AIE and have guided the molecular design of most AIE materials. However, it sometimes fails to be workable to some heteroatom-containing systems. Herein, in this work, we take more than one excited state into account and specify a mechanism –"restriction of access to dark state (RADS)" – to explain the AIE effect of heteroatom-containing molecules. An anthracene-based zinc ion probe named APA is chosen as the model compound, whose weak fluorescence in solution is ascribed to the easy access from the bright (π,π*) state to the closelying dark (n,π*) state caused by the strong vibronic coupling of the two excited states. By either metal complexation or aggregation, the dark state is less accessible due to the restriction of the molecular motion leading to the dark state and elevation of the dark state energy, thus the emission of the bright state is restored. RADS is found to be powerful in elucidating the photophysics of AIE materials with excited states which favor non-radiative decay, including overlap-forbidden states such as (n,π*) and CT states, spin-forbidden triplet states, which commonly exist in heteroatom-containing molecules.

Branching ratios in the radiative decay of helium doubly excited states

2005 ◽  
Vol 72 (5) ◽  
Author(s):  
M. Coreno ◽  
K. C. Prince ◽  
R. Richter ◽  
M. de Simone ◽  
K. Bučar ◽  
...  
Keyword(s):  
Excited States ◽  
Radiative Decay ◽  
Branching Ratios ◽  
Doubly Excited States ◽  
Doubly Excited

Substituent positional effect on radiative lifetimes of anthracene sulphonates

1980 ◽  
Vol 58 (10) ◽  
pp. 1046-1050 ◽  
Author(s):  
A. K. Gupta ◽  
Sekhar Basu ◽  
K. K. Rohatgi-Mukherjee
Keyword(s):  
Sharp Increase ◽  
Decay Constant ◽  
Radiative Decay ◽  
Steric Effect ◽  
Single Photon ◽  
Photon Counting ◽  
Molecular Geometry ◽  
Single Photon Counting ◽  
Decay Constants ◽  
Exciplex Formation

Excited state lifetimes of anthracene-1-sulphonate, anthracene-2-sulphonate, anthracene-1,5-disulphonate, and anthracene-1,8-disulphonate have been studied by photoselection and single photon counting methods. Experimental lifetimes are compared with theoretical values. For anthracene- monosulphonates, exciplex formation with water is proposed. In the case of anthracene-1,8-disulphonate, distortion in molecular geometry is found responsible for the higher non-radiative decay constant. Summation of nonradiative decay constants, Σki, increase in the series [Formula: see text]. The sharp increase for 1,8-AS is perhaps due to distortion of the molecular geometry due to steric effect of two bulky and charged —SO3− groups on the same side of the anthracene skeleton.

Mass spectrum and leptonic decay constants of ground and radially excited states of ηc and ηb in a Bethe–Salpeter equation framework

2015 ◽  
Vol 24 (04) ◽  
pp. 1550030 ◽  
Author(s):  
Hluf Negash ◽  
Shashank Bhatnagar
Keyword(s):  
Mass Spectrum ◽  
Excited States ◽  
Ground State ◽  
Reasonable Agreement ◽  
Equal Mass ◽  
Leptonic Decay ◽  
Decay Constants ◽  
Pseudoscalar Mesons

In this paper, we study the mass spectrum and decay constants of ground state (1S) and radially excited states (2S and 3S) of heavy equal mass pseudoscalar mesons, ηc and ηb. We have employed the framework of Bethe–Salpeter equation (BSE) under Covariant Instantaneous Ansatz (CIA). Our predictions are in reasonable agreement with the data on available states and results of other models.

Radiative decay constants of the H2 Fulcher bands

1978 ◽  
Vol 69 (12) ◽  
pp. 5518-5520 ◽  
Author(s):  
Ray L. Day ◽  
Richard J. Anderson ◽  
Francis A. Sharpton
Keyword(s):  
Radiative Decay ◽  
Decay Constants
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