Solvent effects on the ability of amines to physically quench singlet oxygen as determined by time-resolved infrared emission studies

1989 ◽  
Vol 54 (15) ◽  
pp. 3581-3584 ◽  
Author(s):  
Edward L. Clennan ◽  
L. J. Noe ◽  
T. Wen ◽  
E. Szneler
Keyword(s):  
Singlet Oxygen ◽  
Solvent Effects ◽  
Infrared Emission ◽  
Time Resolved ◽  
Emission Studies ◽  
Quench Singlet Oxygen

Time-resolved infrared emission studies of CO2 formed by CO oxidation on Pt and Pd

1983 ◽  
Vol 102 (1) ◽  
pp. 37-40 ◽  
Author(s):  
David A. Mantell ◽  
Subbarao B. Ryali ◽  
Gary L. Haller
Keyword(s):  
Co Oxidation ◽  
Infrared Emission ◽  
Time Resolved ◽  
Emission Studies

Time-Resolved Pulsed FT-IR Emission Studies of Photochemical Reactions

1993 ◽  
Vol 47 (9) ◽  
pp. 1438-1445 ◽  
Author(s):  
D. E. Heard ◽  
R. A. Brownsword ◽  
D. G. Weston ◽  
G. Hancock
Keyword(s):  
Plasma Etching ◽  
Infrared Emission ◽  
Photochemical Reactions ◽  
Quantum Yields ◽  
Time Resolved ◽  
Ion Plasma ◽  
Ft Ir ◽  
Ir Emission ◽  
Product Species ◽  
Emission Studies

A time-resolved Fourier transform emission spectrometer, operating in the stop-scan mode, is demonstrated as an inexpensive and versatile instrument for observation of infrared vibrational chemiluminescence. The entire evolution of an emission spectrum is obtained from a single scan of the interferometer, with a spectral and temporal resolution of 2 cm−1 and 10 ns, respectively. Results are presented for a number of radical-radical reactions studied by this technique, where emission from highly excited CO, HF, CO2, and N2O is observed. Measurements include nascent vibrational distributions, quantum yields for branching into different product channels, and bimolecular rate constants for the production and vibrational relaxation of product species. Experiments at low total pressure enable nascent vibrational and rotational distributions to be found for the HF fragment of the CO2 laser photolysis of 1,1-chlorofluoroethylene. In addition, time-resolved spectra of HF, CO, CO2, CF4, and CHF3 are demonstrated for infrared emission observed from a reactive ion plasma etching chamber.

scholarly journals Photophysical Properties of Protoporphyrin IX, Pyropheophorbide-a, and Photofrin® in Different Conditions

2021 ◽  
Vol 14 (2) ◽  
pp. 138
Author(s):  
Bauyrzhan Myrzakhmetov ◽  
Philippe Arnoux ◽  
Serge Mordon ◽  
Samir Acherar ◽  
Irina Tsoy ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Photophysical Properties ◽  
Protoporphyrin Ix ◽  
Fluorescence Emission ◽  
Solvent Polarity ◽  
Visible Absorption ◽  
Light Dosimetry ◽  
Time Resolved ◽  
Pyropheophorbide A ◽  
Influence Of Solvent

Photodynamic therapy (PDT) is an innovative treatment of malignant or diseased tissues. The effectiveness of PDT depends on light dosimetry, oxygen availability, and properties of the photosensitizer (PS). Depending on the medium, photophysical properties of the PS can change leading to increase or decrease in fluorescence emission and formation of reactive oxygen species (ROS) especially singlet oxygen (1O2). In this study, the influence of solvent polarity, viscosity, concentration, temperature, and pH medium on the photophysical properties of protoporphyrin IX, pyropheophorbide-a, and Photofrin® were investigated by UV-visible absorption, fluorescence emission, singlet oxygen emission, and time-resolved fluorescence spectroscopies.

scholarly journals Photoreactivity of Hair Melanin from Different Skin Phototypes—Contribution of Melanin Subunits to the Pigments Photoreactive Properties

2021 ◽  
Vol 22 (9) ◽  
pp. 4465
Author(s):  
Krystian Mokrzynski ◽  
Shosuke Ito ◽  
Kazumasa Wakamatsu ◽  
Theodore G. Camenish ◽  
Tadeusz Sarna ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Singlet Oxygen ◽  
Near Infrared ◽  
Paramagnetic Resonance ◽  
Time Resolved ◽  
W Band ◽  
Epr Oximetry ◽  
X Band ◽  
Hair Samples ◽  
Electron Paramagnetic

Photoreactivity of melanin has become a major focus of research due to the postulated involvement of the pigment in UVA-induced melanoma. However, most of the hitherto studies were carried out using synthetic melanin models. Thus, photoreactivity of natural melanins is yet to be systematically analyzed. Here, we examined the photoreactive properties of natural melanins isolated from hair samples obtained from donors of different skin phototypes (I, II, III, and V). X-band and W-band electron paramagnetic resonance (EPR) spectroscopy was used to examine the paramagnetic properties of the pigments. Alkaline hydrogen peroxide degradation and hydroiodic acid hydrolysis were used to determine the chemical composition of the melanins. EPR oximetry and spin trapping were used to examine the oxygen photoconsumption and photo-induced formation of superoxide anion, and time-resolved near infrared phosphorescence was employed to determine the singlet oxygen photogeneration by the melanins. The efficiency of superoxide and singlet oxygen photogeneration was related to the chemical composition of the studied melanins. Melanins from blond and chestnut hair (phototypes II and III) exhibited highest photoreactivity of all examined pigments. Moreover, melanins of these phototypes showed highest quantum efficiency of singlet oxygen photogeneration at 332 nm and 365 nm supporting the postulate of the pigment contribution in UVA-induced melanoma.

scholarly journals Study of Singlet Oxygen Dynamics on Silicon Polymer Matrix

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Jeong-Wook Hwang ◽  
Seung-Jin Jung ◽  
Il Heo ◽  
Hyun-A Son ◽  
Jong-Ho Kim ◽  
...  
Keyword(s):  
Singlet Oxygen ◽  
Detailed Analysis ◽  
Polymer Film ◽  
Polymer Matrix ◽  
Time Resolved ◽  
Surface Component ◽  
Component C ◽  
Oxygen Dynamics ◽  
Silicone Polymer

We report a detailed analysis of singlet oxygen generated from the photofunctional polymer film (PFPF) matrix which is the silicone polymer film (PDMS) embedded with a photosensitizer. Activation and deactivation dynamics of singlet oxygen generated from PFPFs were investigated with time-resolved phosphorescence spectroscopy. The singlet oxygen generated from PFPFs was dissipated into three different regions of the polymer matrix; the inside (component A), the surface (component B), and the outside (component C). According to the deactivation dynamics of singlet oxygen in the polymer matrix, the components B and C are expected to be more important for various applications.

Picosecond time-resolved absorption and emission studies of pyrazolotriazole azomethine dyes

1991 ◽  
Vol 87 (21) ◽  
pp. 3479 ◽  
Author(s):  
Peter Douglas ◽  
Stewart M. Townsend ◽  
Paula J. Booth ◽  
Ben Crystall ◽  
James R. Durrant ◽  
...  
Keyword(s):  
Time Resolved ◽  
Absorption And Emission ◽  
Emission Studies
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