scholarly journals A wavelength dependent investigation of the indole photophysics via ionization and fragmentation pump–probe spectroscopies

2015 ◽  
Vol 17 (38) ◽  
pp. 25197-25209 ◽  
Author(s):  
T. J. Godfrey ◽  
Hui Yu ◽  
Michael S. Biddle ◽  
Susanne Ullrich

Using a variety of gas-phase pump–probe spectroscopic techniques, this work investigates indole excited-state relaxation dynamics at several pump wavelengths with a particular focus on 1πσ*-state involvement.

2017 ◽  
Vol 19 (34) ◽  
pp. 22785-22800 ◽  
Author(s):  
S. V. Kruppa ◽  
F. Bäppler ◽  
W. Klopper ◽  
S. P. Walg ◽  
W. R. Thiel ◽  
...  

The [Ag2(dcpm)2]2+ phosphine complex displays multiexponential excited-state relaxation dynamics both in the gas phase and in solution.


2018 ◽  
Vol 20 (19) ◽  
pp. 13400-13411 ◽  
Author(s):  
Dipak Kumar Das ◽  
Krishnandu Makhal ◽  
Debabrata Goswami

Using a degenerate pump probe technique at 800 nm, Ground State Vibrational Coherence (GSVC) of a cyanine dye (IR780) is explored in various solvents.


2016 ◽  
Vol 113 (50) ◽  
pp. E8011-E8020 ◽  
Author(s):  
Laura B. Hoch ◽  
Paul Szymanski ◽  
Kulbir Kaur Ghuman ◽  
Le He ◽  
Kristine Liao ◽  
...  

In2O3-x(OH)y nanoparticles have been shown to function as an effective gas-phase photocatalyst for the reduction of CO2 to CO via the reverse water–gas shift reaction. Their photocatalytic activity is strongly correlated to the number of oxygen vacancy and hydroxide defects present in the system. To better understand how such defects interact with photogenerated electrons and holes in these materials, we have studied the relaxation dynamics of In2O3-x(OH)y nanoparticles with varying concentration of defects using two different excitation energies corresponding to above-band-gap (318-nm) and near-band-gap (405-nm) excitations. Our results demonstrate that defects play a significant role in the excited-state, charge relaxation pathways. Higher defect concentrations result in longer excited-state lifetimes, which are attributed to improved charge separation. This correlates well with the observed trends in the photocatalytic activity. These results are further supported by density-functional theory calculations, which confirm the positions of oxygen vacancy and hydroxide defect states within the optical band gap of indium oxide. This enhanced understanding of the role these defects play in determining the optoelectronic properties and charge carrier dynamics can provide valuable insight toward the rational development of more efficient photocatalytic materials for CO2 reduction.


Author(s):  
E. G. Rightor

Core edge spectroscopy methods are versatile tools for investigating a wide variety of materials. They can be used to probe the electronic states of materials in bulk solids, on surfaces, or in the gas phase. This family of methods involves promoting an inner shell (core) electron to an excited state and recording either the primary excitation or secondary decay of the excited state. The techniques are complimentary and have different strengths and limitations for studying challenging aspects of materials. The need to identify components in polymers or polymer blends at high spatial resolution has driven development, application, and integration of results from several of these methods.


Author(s):  
Branislav Milovanović ◽  
Jurica Novak ◽  
Mihajlo Etinski ◽  
Wolfgang Domcke ◽  
Nadja Doslic

Despite many studies, the mechanisms of nonradiative relaxation of uracil in the gas phase and in aqueous solution are still not fully resolved. Here we combine theoretical UV absorption spectroscopy...


2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Chunfan Yang ◽  
Qian Zhou ◽  
Zeqing Jiao ◽  
Hongmei Zhao ◽  
Chun-Hua Huang ◽  
...  

AbstractThe triplet metal to ligand charge transfer (3MLCT) luminescence of ruthenium (II) polypyridyl complexes offers attractive imaging properties, specifically towards the development of sensitive and structure-specific DNA probes. However, rapidly-deactivating dark state formation may compete with 3MLCT luminescence depending on different DNA structures. In this work, by combining femtosecond and nanosecond pump-probe spectroscopy, the 3MLCT relaxation dynamics of [Ru(phen)2(dppz)]2+ (phen = 1,10-phenanthroline, dppz = dipyridophenazine) in two iconic G-quadruplexes has been scrutinized. The binding modes of stacking of dppz ligand on the terminal G-quartet fully and partially are clearly identified based on the biexponential decay dynamics of the 3MLCT luminescence at 620 nm. Interestingly, the inhibited dark state channel in ds-DNA is open in G-quadruplex, featuring an ultrafast picosecond depopulation process from 3MLCT to a dark state. The dark state formation rates are found to be sensitive to the content of water molecules in local G-quadruplex structures, indicating different patterns of bound water. The unique excited state dynamics of [Ru(phen)2(dppz)]2+ in G-quadruplex is deciphered, providing mechanistic basis for the rational design of photoactive ruthenium metal complexes in biological applications.


2016 ◽  
Vol 656 ◽  
pp. 573-580 ◽  
Author(s):  
W. Ryba-Romanowski ◽  
J. Komar ◽  
T. Niedźwiedzki ◽  
M. Głowacki ◽  
M. Berkowski

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