scholarly journals Measurement of Radiative Decay of Λ(1405) by Using Hyperon Spectrometer at J-PARC

2017 ◽  
Author(s):  
S. H. Hwang ◽  
K. Imai
Keyword(s):  
Radiative Decay

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.

scholarly journals Temperature-Dependent Stimulated Emission Cross-Section in Nd3+:YLF Crystal

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 431
Author(s):  
Giorgio Turri ◽  
Scott Webster ◽  
Michael Bass ◽  
Alessandra Toncelli
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Room Temperature ◽  
Radiative Decay ◽  
Emission Cross Section ◽  
Spectroscopic Properties ◽  
Stimulated Emission ◽  
Different Temperatures ◽  
Stimulated Emission Cross Section ◽  
Semi Empirical

Spectroscopic properties of neodymium-doped yttrium lithium fluoride were measured at different temperatures from 35 K to 350 K in specimens with 1 at% Nd3+ concentration. The absorption spectrum was measured at room temperature from 400 to 900 nm. The decay dynamics of the 4F3/2 multiplet was investigated by measuring the fluorescence lifetime as a function of the sample temperature, and the radiative decay time was derived by extrapolation to 0 K. The stimulated-emission cross-sections of the transitions from the 4F3/2 to the 4I9/2, 4I11/2, and 4I13/2 levels were obtained from the fluorescence spectrum measured at different temperatures, using the Aull–Jenssen technique. The results show consistency with most results previously published at room temperature, extending them over a broader range of temperatures. A semi-empirical formula for the magnitude of the stimulated-emission cross-section as a function of temperature in the 250 K to 350 K temperature range, is presented for the most intense transitions to the 4I11/2 and 4I13/2 levels.

Radiative decay rates in LaF3:Dy3+

1979 ◽  
Vol 63 (1) ◽  
pp. 90-92 ◽  
Author(s):  
H. Jagannath ◽  
A. Sivaram ◽  
D. Ramachandra Rao ◽  
P. Venkateswarlu
Keyword(s):  
Radiative Decay ◽  
Decay Rates

Competition between radiative decay and energy relaxation of carriers in disorderedInxGa1−xAs/GaAsquantum wells

2000 ◽  
Vol 61 (16) ◽  
pp. 10985-10993 ◽  
Author(s):  
M. Grassi Alessi ◽  
F. Fragano ◽  
A. Patanè ◽  
M. Capizzi ◽  
E. Runge ◽  
...  
Keyword(s):  
Radiative Decay ◽  
Energy Relaxation

SELF-TRAPPED EXCITONS IN ORTHORHOMBIC SnBr2

2001 ◽  
Vol 15 (28n30) ◽  
pp. 4009-4012 ◽  
Author(s):  
Y. YAMASAKI ◽  
N. OHNO
Keyword(s):  
Time Dependence ◽  
Low Temperatures ◽  
Luminescence Band ◽  
Radiative Decay ◽  
Time Resolved ◽  
Tunneling Recombination ◽  
Exciton Region ◽  
Time Resolved Photoluminescence ◽  
Stokes Shifts ◽  
2.5 Ev Luminescence

Luminescence properties of SnBr 2 have been studied to reveal the photo-excited exciton relaxation process. Two types of luminescence with large Stokes shifts are found at low temperatures; the 2.2-eV luminescence band produced under the photo-excitation in the first exciton region, and the 2.5-eV luminescence band stimulated by photons with energies above the bandgap. The time-resolved photoluminescence measurements have revealed that the 2.2-eV luminescence comprises fast (1.2 μs) and slow (6.4 μs) exponential decay components, whereas the 2.5-eV luminescence shows the time dependence of I(t)∞ t-0.9. These results suggest that the former band is attributed to the radiative decay of self-trapped excitons, and the latter band would originate from tunneling recombination of holes with the STEL as in the case of lead halides.

Taming the excited state reactivity of imines – from non-radiative decay to aza Paternò–Büchi reaction

2021 ◽  
Author(s):  
Sunil Kumar Kandappa ◽  
Lakshmy Kannadi Valloli ◽  
Sapna Ahuja ◽  
Jayachandran Parthiban ◽  
J. Sivaguru
Keyword(s):  
Excited State ◽  
Radiative Decay ◽  
Photophysical Properties

This review highlights the excited state characteristics of imines and processes that govern their photochemical and photophysical properties.

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