Electronic quenching, rotational relaxation, and radiative lifetime of NH(A 3Π, v’=0, N’)

1985 ◽  
Vol 82 (7) ◽  
pp. 3152-3159 ◽  
Author(s):  
A. Hofzumahaus ◽  
F. Stuhl
Keyword(s):  
Radiative Lifetime ◽  
Rotational Relaxation

The OH Meinel bands in the airglow—the radiative lifetime

1978 ◽  
Vol 56 (5) ◽  
pp. 581-586 ◽  
Author(s):  
E. J. Llewellyn ◽  
B. H. Long
Keyword(s):  
Rate Constants ◽  
Rotational Temperature ◽  
Radiative Lifetime ◽  
Rotational Relaxation ◽  
Vibrational Levels

A model of the rotational relaxation of an emitting population has been used to determine the rotational temperature of emitted spectra for the OH Meinel bands. It is shown that the calculated rotational temperatures for these spectra are consistent with laboratory observations of the hydrogen–ozone reaction if the radiative lifetime for the Meinel bands is short, [Formula: see text]The model is also used to infer the initial rotational populations of the OH vibrational levels excited in the hydrogen–ozone reaction. It has been found that these initial rotational populations may be described by rotational temperatures of 1940, 1230, and 760 K for the seventh, eighth, and ninth vibrational levels, respectively. It is also concluded that the rate constants for vibrational quenching will be increased from previously accepted values. The effect of a short radiative lifetime for airglow observations is also discussed.

Two-Dimensional Infrared Spectroscopy From the Gas to Liquid Phase: Density Dependent J-Scrambling, Vibrational Relaxation, and the Onset of Liquid Character

2019 ◽  
Author(s):  
Greg Ng Pack ◽  
Matthew Rotondaro ◽  
Parth Shah ◽  
Aritra Mandal ◽  
Shyamsunder Erramilli ◽  
...  
Keyword(s):  
Vibrational Energy ◽  
Rotational Relaxation ◽  
Vibrational Energy Relaxation ◽  
Pump Probe ◽  
Solution Dynamics ◽  
Supercritical Phase ◽  
Supercritical Solution ◽  
Asymmetric Stretch ◽  
Two Dimensional Infrared Spectroscopy ◽  
Vibrational Equilibrium

Ultrafast 2DIR spectra and pump-probe responses of the N2O n 3 asymmetric stretch in SF6 as a function of density from the gas to supercritical phase and liquid are reported. 2DIR spectra unequivocally reveal free rotor character at all densities studied in the gas and supercritical region. Analysis of the 2DIR spectra determines that J-scrambling or rotational relaxation in N2O is highly efficient, occurring in ~1.5 to ~2 collisions with SF6 at all non-liquid densities. In contrast, N2O n 3 vibrational energy relaxation requires ~15 collisions, and complete vibrational equilibrium occurs on the ~ns scale at all densities. An independent binary collision model is sufficient to describe these supercritical state point dynamics. The N2O n 3 in liquid SF6 2DIR spectrum shows no evidence of free rotor character or spectral diffusion. Using these 2DIR results, hindered rotor or liquid-like character is found in gas and all supercritical solutions for SF6 densities ³ r * = 0.3, and increases with SF6 density. 2DIR spectral analysis offers direct time domain evidence of critical slowing for SF6 solutions closest to the critical point density. Applications of 2DIR to other high density and supercritical solution dynamics and descriptions are discussed. <br>

Vibrational and Rotational Relaxation in Sulfur Dioxide

1971 ◽  
Vol 54 (2) ◽  
pp. 644-647 ◽  
Author(s):  
H. E. Bass ◽  
T. G. Winter ◽  
L. B. Evans
Keyword(s):  
Sulfur Dioxide ◽  
Rotational Relaxation ◽  
Vibrational And Rotational Relaxation

Modified radiative lifetime of Eu3+ ions in Y2O3 thin films on Al2O3 substrates

2021 ◽  
Vol 230 ◽  
pp. 117754
Author(s):  
S.P. Feofilov ◽  
A.M. Korovin ◽  
A.B. Kulinkin ◽  
D.S. Kuzin ◽  
A.N. Smirnov ◽  
...  
Keyword(s):  
Thin Films ◽  
Radiative Lifetime

Rotational Relaxation of AlNC and AlCN by para-H2 (j = 0) at Low Temperatures

2020 ◽  
Vol 4 (12) ◽  
pp. 2384-2390
Author(s):  
Rodrigo Urzúa-Leiva ◽  
Otoniel Denis-Alpizar
Keyword(s):  
Low Temperatures ◽  
Rotational Relaxation

Synthesis and size control of Si nanocrystals by SiO/SiO2 superlattices and Er doping

2002 ◽  
Vol 737 ◽  
Author(s):  
J. Heitmann ◽  
D. Kovalev ◽  
M. Schmidt ◽  
L.X. Yi ◽  
R. Scholz ◽  
...  
Keyword(s):  
Phase Separation ◽  
Crystal Size ◽  
Radiative Lifetime ◽  
Size Control ◽  
Luminescence Signal ◽  
Er Doping ◽  
Size Dependent ◽  
Transmission Electron ◽  
Si Nanocrystals ◽  
Ultrathin Layers

ABSTRACTThe synthesis of nc-Si by reactive evaporation of SiO and subsequent thermal induced phase separation is reported. The size control of nc-Si is realized by evaporation of SiO/SiO2 superlattices. By this method an independent control of crystal size and density is possible. The phase separation of SiO into SiO2 and nc-Si in the limit of ultrathin layers is investigated. Different steps of this phase separation are characterized by photoluminescence, infrared absorption and transmission electron microscopy measurements. The strong room temperature luminescence of nc-Si shows a strong blueshift of the photoluminescence signal from 850 to 750 nm with decreasing crystal size. Several size dependent properties of this luminescence signal, like decreasing radiative lifetime and increasing no-phonon transition properties with decreasing crystal size are in good agreement with the quantum confinement model. Er doping of the nc-Si shows an enhancement of the Er luminescence at 1.54 μm by a factor of 5000 compared to doped SiO2 layers. The decreasing transfer time for the nc-Si to Er transition with decreasing crystal size can be understood as additional proof of increasing recombination probability within the nc-Si for decreasing crystal size.

scholarly journals Radiative properties of quantum emitters in boron nitride from excited state calculations and Bayesian analysis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Shiyuan Gao ◽  
Hsiao-Yi Chen ◽  
Marco Bernardi
Keyword(s):  
Boron Nitride ◽  
Density Functional ◽  
Single Photon ◽  
Radiative Lifetime ◽  
Radiative Properties ◽  
Data Set ◽  
Radiative Lifetimes ◽  
Emission Energy ◽  
Single Photon Emitters ◽  
Quantum Emitters

AbstractPoint defects in hexagonal boron nitride (hBN) have attracted growing attention as bright single-photon emitters. However, understanding of their atomic structure and radiative properties remains incomplete. Here we study the excited states and radiative lifetimes of over 20 native defects and carbon or oxygen impurities in hBN using ab initio density functional theory and GW plus Bethe-Salpeter equation calculations, generating a large data set of their emission energy, polarization and lifetime. We find a wide variability across quantum emitters, with exciton energies ranging from 0.3 to 4 eV and radiative lifetimes from ns to ms for different defect structures. Through a Bayesian statistical analysis, we identify various high-likelihood charge-neutral defect emitters, among which the native VNNB defect is predicted to possess emission energy and radiative lifetime in agreement with experiments. Our work advances the microscopic understanding of hBN single-photon emitters and introduces a computational framework to characterize and identify quantum emitters in 2D materials.

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