Probe Position-Dependent Counterion Dynamics in DNA: Comparison of Time-Resolved Stokes Shift of Groove-Bound to Base-Stacked Probes in the Presence of Different Monovalent Counterions

2012 ◽  
Vol 3 (18) ◽  
pp. 2621-2626 ◽  
Author(s):  
Sachin Dev Verma ◽  
Nibedita Pal ◽  
Moirangthem Kiran Singh ◽  
Sobhan Sen
Keyword(s):  
Stokes Shift ◽  
Probe Position ◽  
Time Resolved

scholarly journals Dynamics of Anomalous Temperature-Induced Emission Shift in MOCVD-grown (Al, In)GaN Thin Films

2000 ◽  
Vol 5 (S1) ◽  
pp. 796-802 ◽  
Author(s):  
Yong-Hoon Cho ◽  
G. H. Gainer ◽  
J. B. Lam ◽  
J. J. Song ◽  
W Yang ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Stokes Shift ◽  
Energy Shift ◽  
Peak Position ◽  
Time Resolved ◽  
Temperature Range ◽  
Al Content ◽  
Peak Energy ◽  
Emission Behavior ◽  
Pl Intensity

We present a comprehensive study of the optical characteristics of (Al, In)GaN epilayers measured by photoluminescence (PL), integrated PL intensity, and time-resolved PL spectroscopy. For not only InGaN, but also AlGaN epilayers with large Al content, we observed an anomalous PL temperature dependence: (i) an “S-shaped” PL peak energy shift (decrease-increase-decrease) and (ii) an “inverted S-shaped” full width at half maximum (FWHM) change (increase-decrease-increase) with increasing temperature. Based on time-resolved PL, the S shape (inverted S shape) of the PL peak position (FWHM) as a function of temperature, and the much smaller PL intensity decrease in the temperature range showing the anomalous emission behavior, we conclude that strong localization of carriers occurs in InGaN and even in AlGaN with rather high Al content. We observed that the following increase with increasing Al content in AlGaN epilayers: (i) a Stokes shift between the PL peak energy and the absorption edge, (ii) a redshift of the emission with decay time, (iii) the deviations of the PL peak energy, FWHM, and PL intensity from their typical temperature dependence, and (iv) the corresponding temperature range of the anomalous emission behavior. This indicates that the band-gap fluctuation responsible for these characteristics is due to energy tail states caused by non-random inhomogeneous alloy potential variations enhanced with increasing Al content.

On the large apparent Stokes shift of phthalimides

2019 ◽  
Vol 21 (9) ◽  
pp. 4839-4853 ◽  
Author(s):  
Anna Reiffers ◽  
Christian Torres Ziegenbein ◽  
Luiz Schubert ◽  
Janina Diekmann ◽  
Kristoffer A. Thom ◽  
...  
Keyword(s):  
Steady State ◽  
Absorption Spectroscopy ◽  
Stokes Shift ◽  
Time Resolved Fluorescence ◽  
Time Resolved

The photophysics of N-methylphthalimide (MP) in solution (cyclohexane, ethanol, acetonitrile, and water) was characterized by steady state as well as time resolved fluorescence and absorption spectroscopy.

Mechanism Behind the Apparent Large Stokes Shift in LSSmOrange Investigated by Time-Resolved Spectroscopy

2015 ◽  
Vol 119 (47) ◽  
pp. 14880-14891 ◽  
Author(s):  
Eduard Fron ◽  
Herlinde De Keersmaecker ◽  
Susana Rocha ◽  
Yannick Baeten ◽  
Gang Lu ◽  
...  
Keyword(s):  
Stokes Shift ◽  
Time Resolved ◽  
Time Resolved Spectroscopy ◽  
Large Stokes Shift

Wavelength- and Time-Resolved Luminescence Spectroscopy for Investigation of the Matrix-Assisted Laser Desorption Process

2002 ◽  
Vol 8 (4) ◽  
pp. 287-293 ◽  
Author(s):  
Carsten Zechmann ◽  
Tassilo Muskat ◽  
Jürgen Grotemeyer
Keyword(s):  
Ionization Energy ◽  
Stokes Shift ◽  
Laser Desorption ◽  
Luminescence Spectroscopy ◽  
Time Resolved ◽  
Fluorescence Measurements ◽  
The Matrix ◽  
Stokes Shifts ◽  
Matrix Assisted Laser ◽  
Matrix Assisted Laser Desorption

This work deals with investigations of fluorescence phenomena during interaction of ultraviolet laser radiation with four substances (2,5-dihydroxybenzoic acid, 3-hydroxypicolinic acid, dithranol and ferulic acid) commonly used as matrices in matrix-assisted laser desorption/ionization (MALDI). Wavelength-resolved fluorescence measurements allowed classification of UV-MALDI matrices on the basis of their Stokes shift. Matrices showing a high Stokes shift dissipated high amounts of laser energy by means of intra- and intermolecular energy transfer processes, hence contributing less to the ionization of analyte compounds. Conversely, matrix substances with a low Stokes shift retained more of the original photonic energy which may then be available for ionization within the matrix or after desorption of molecular species. Therefore matrix compounds can be designated as “hard” (high ionization energy) in the case of small Stokes shifts or “soft” (low ionization energy) in the case of high Stokes shifts. Time-resolved measurements showed fluorescence lifetimes below 5 ns for all four substances.

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