scholarly journals Substrate effects in the photoenhanced ozonation of pyrene

2011 ◽  
Vol 11 (3) ◽  
pp. 1243-1253 ◽  
Author(s):  
S. A. Styler ◽  
M.-E. Loiseaux ◽  
D. J. Donaldson
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Gas Phase ◽  
Ozone Concentration ◽  
Aqueous Interfaces ◽  
Substrate Effects ◽  
Environmental Surfaces ◽  
Laboratory Results ◽  
Reactive Surfaces ◽  
Kinetics Of

Abstract. We report the effects of actinic illumination on the heterogeneous ozonation kinetics of solid pyrene films and pyrene adsorbed at air-octanol and air-aqueous interfaces. Upon illumination, the ozonation of solid pyrene films and pyrene at the air-aqueous interface proceeds more quickly than in darkness; no such enhancement is observed for pyrene at the air-octanol interface. Under dark conditions, the reaction of pyrene at all three interfaces proceeds via a Langmuir-Hinshelwood-type surface mechanism. In the presence of light, Langmuir-Hinshelwood kinetics are observed for solid pyrene films but a linear dependence upon gas-phase ozone concentration is observed at the air-aqueous interface. We interpret these results as evidence of the importance of charge-transfer pathways for the ozonation of excited-state pyrene. The dramatically different behaviour of pyrene at the surface of these three simple reaction environments highlights the difficulties inherent in representing complex reactive surfaces in the laboratory, and suggests caution in extrapolating laboratory results to environmental surfaces.

scholarly journals Substrate effects in the photoenhanced ozonation of pyrene

2010 ◽  
Vol 10 (11) ◽  
pp. 27825-27852
Author(s):  
S. A. Styler ◽  
M.-E. Loiseaux ◽  
D. J. Donaldson
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Gas Phase ◽  
Ozone Concentration ◽  
Aqueous Interfaces ◽  
Substrate Effects ◽  
Environmental Surfaces ◽  
Laboratory Results ◽  
Reactive Surfaces ◽  
Kinetics Of

Abstract. We report the effects of actinic illumination on the heterogeneous ozonation kinetics of solid pyrene films and pyrene adsorbed at air-octanol and air-aqueous interfaces. Upon illumination, the ozonation of solid pyrene films and pyrene at the air-aqueous interface proceeds more quickly than in darkness; no such enhancement is observed for pyrene at the air-octanol interface. Under dark conditions, the reaction of pyrene at all three interfaces proceeds via a Langmuir-Hinshelwood-type surface mechanism. In the presence of light, Langmuir-Hinshelwood kinetics are observed for solid pyrene films but a linear dependence upon gas-phase ozone concentration is observed at the air-aqueous interface. We interpret these results as evidence of the importance of charge-transfer pathways for the ozonation of excited-state pyrene. The dramatically different behaviour of pyrene at the surface of these three simple reaction environments highlights the difficulties inherent in representing complex reactive surfaces in the laboratory, and suggests caution in extrapolating laboratory results to environmental surfaces.

scholarly journals Excited States and Intermediates by Time-Resolved Infrared Spectroscopy

1999 ◽  
Vol 19 (1-4) ◽  
pp. 245-251 ◽  
Author(s):  
J. J. Turner ◽  
M. W. George ◽  
I. P. Clark ◽  
I. G. Virrels
Keyword(s):  
Infrared Spectroscopy ◽  
Excited State ◽  
Charge Transfer ◽  
Excited States ◽  
Fast Time ◽  
Time Resolved ◽  
Excited Species ◽  
Charge Transfer Transitions ◽  
Time Resolved Infrared Spectroscopy ◽  
Kinetics Of

For coordination compounds containing CO or CN groups, fast time-resolved infrared spectroscopy (TRIR) provides a convenient method of probing excited states and intermediates. TRIR has proved particularly powerful for probing the structure and kinetics of organometallic intermediates. The interpretation is particularly straightforward when combined with IR data from matrix isolation experiments, although there can be some subtle differences. In excited state studies, shifts in ν(CO) and ν(CN) frequencies, from ground to excited state, are sensitive to the changes in electron distribution on excitation, thus allowing the distinction between charge-transfer and non-charge-transfer transitions. Subtle effects on excited state ν(CO) band positions occur with change from fluid to rigid solvent-“infrared rigidochromism”. There is often a change in ν(CO) band width on excitation; this can be interpreted in terms of specific interactions between the excited species and the solvent. This paper presents some of our recent work in this area.

STUDY OF THE S1 AND S2 EXCITED STATES OF GAS-PHASE PROTONATED SCHIFF BASE RETINAL CHROMOPHORES IN ONE AND TWO PHOTON ABSORPTION

2011 ◽  
Vol 10 (02) ◽  
pp. 121-132 ◽  
Author(s):  
YUANZUO LI ◽  
PENG SONG ◽  
YING SHI ◽  
YONG DING ◽  
FENGJIE ZHOU ◽  
...  
Keyword(s):  
Schiff Base ◽  
Excited State ◽  
Charge Transfer ◽  
Gas Phase ◽  
Excited States ◽  
Density Functional ◽  
Three Dimensional ◽  
Photon Absorption ◽  
Two Photon ◽  
The One

The S1 and S2 excited states of gas-phase protonated Schiff base retinal chromophores in the one- and two-photon absorptions (TPAs) are investigated with time-dependent density functional theory. In one-photon absorption, the two-dimensional (2D) site and three-dimensional (3D) cube representations reveal that S1 and S2 excited states of gas-phase protonated Schiff base retinal chromophores are all charge transfer excited states. To better study the weak S2 excited states of gas-phase protonated Schiff base retinal chromophores, we investigated theoretically excited state properties of them in TPA. For 11-cis dimethyl retinal, it is found that the cross section of S2 excited state is 51.04 GM in PTA, which is only slightly smaller than that of S1 (77.04 GM) in TPA. Therefore, the S2 excited state of 11-cis dimethyl retinal can be clearly observed in TPA experiment. The 2D site and 3D cube representations reveal that electronic transition from S1 to S2 excited state of gas-phase protonated Schiff base retinal chromophores in TPA are also of charge transfer character.

Integration of Core-Edge Spectroscopy Methods for the Study of Polymers

1996 ◽  
Vol 54 ◽  
pp. 154-155
Author(s):  
E. G. Rightor
Keyword(s):  
Excited State ◽  
Polymer Blends ◽  
Gas Phase ◽  
Spatial Resolution ◽  
High Spatial Resolution ◽  
Electronic States ◽  
Core Electron ◽  
Bulk Solids ◽  
Development Application

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.

Dynamic adjustment of emission from both singlets and triplets: the role of excited state conformation relaxation and charge transfer in phenothiazine derivates

2021 ◽  
Author(s):  
Weidong Qiu ◽  
Xinyi Cai ◽  
Mengke Li ◽  
Liangying Wang ◽  
Yanmei He ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Intramolecular Charge Transfer ◽  
Dynamic Adjustment ◽  
Twisted Intramolecular Charge Transfer

Dynamic adjustment of emission behaviours by controlling the extent of twisted intramolecular charge transfer character in excited state.

Diffusion model for deposition of epitaxial GaAs layers prepared by the MOCVD method

1991 ◽  
Vol 56 (10) ◽  
pp. 2020-2029
Author(s):  
Jindřich Leitner ◽  
Petr Voňka ◽  
Josef Stejskal ◽  
Přemysl Klíma ◽  
Rudolf Hladina
Keyword(s):  
Experimental Data ◽  
Growth Rate ◽  
Kinetic Model ◽  
Gas Phase ◽  
Substrate Surface ◽  
Deposition Process ◽  
Hydrogen Atmosphere ◽  
Epitaxial Gaas ◽  
Kinetics Of ◽  
Good Agreement

The authors proposed and treated quantitatively a kinetic model for deposition of epitaxial GaAs layers prepared by reaction of trimethylgallium with arsine in hydrogen atmosphere. The transport of gallium to the surface of the substrate is considered as the controlling process. The influence of the rate of chemical reactions in the gas phase and on the substrate surface on the kinetics of the deposition process is neglected. The calculated dependence of the growth rate of the layers on the conditions of the deposition is in a good agreement with experimental data in the temperature range from 600 to 800°C.

Novel Carbazole-based Multifunctional Materials with Hybridized Local and Charge-Transfer Excited State Acting as Deep Blue Emitters and Phosphorescent Hosts for Highly Efficient Organic Light-Emitting Diodes

2021 ◽  
Author(s):  
Haitao Zhou ◽  
Mengna Yin ◽  
Zhenhong Zhao ◽  
Yanqin Miao ◽  
Xin Jin ◽  
...  
Keyword(s):  
Excited State ◽  
Charge Transfer ◽  
Light Emitting Diodes ◽  
Organic Light Emitting Diodes ◽  
Multifunctional Materials ◽  
Light Emitting ◽  
Highly Efficient ◽  
Deep Blue ◽  
Organic Light ◽  
Blue Emitters

In this work, two carbazole- and benzo[d]oxazole-based novel multifunctional materials with hybridized local and charge-transfer (HLCT) characteristic, namely OCI and OCT, which could act as deep-blue fluorophors and phosphorescent hosts,...

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