Photo-oxidation Dynamics in GaSe Flakes Probed through Temporal Evolution of Raman Spectroscopy

2021 ◽  
Author(s):  
Sufeng Quan ◽  
Yingying Wang ◽  
Jie Jiang ◽  
Shiyou Fu ◽  
Zhonglin Li ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
Temporal Evolution ◽  
Photo Oxidation

scholarly journals Development and chamber evaluation of the MCM v3.2 degradation scheme for β-caryophyllene

2012 ◽  
Vol 12 (11) ◽  
pp. 5275-5308 ◽  
Author(s):  
M. E. Jenkin ◽  
K. P. Wyche ◽  
C. J. Evans ◽  
T. Carr ◽  
P. S. Monks ◽  
...  
Keyword(s):  
Gas Phase ◽  
Temporal Evolution ◽  
Degradation Mechanism ◽  
Chemical Mechanism ◽  
Oh Radicals ◽  
Photo Oxidation ◽  
Primary Yield ◽  
Chamber Studies ◽  
The Impact ◽  
Tof Ms

Abstract. A degradation mechanism for β-caryophyllene has recently been released as part of version 3.2 of the Master Chemical Mechanism (MCM v3.2), describing the gas phase oxidation initiated by reaction with ozone, OH radicals and NO3 radicals. A detailed overview of the construction methodology is given, within the context of reported experimental and theoretical mechanistic appraisals. The performance of the mechanism has been evaluated in chamber simulations in which the gas phase chemistry was coupled to a representation of the gas-to-aerosol partitioning of 280 multi-functional oxidation products. This evaluation exercise considered data from a number of chamber studies of either the ozonolysis of β-caryophyllene, or the photo-oxidation of β-caryophyllene/NOx mixtures, in which detailed product distributions have been reported. This includes the results of a series of photo-oxidation experiments performed in the University of Manchester aerosol chamber, also reported here, in which a comprehensive characterization of the temporal evolution of the organic product distribution in the gas phase was carried out, using Chemical Ionisation Reaction Time-of-Flight Mass Spectrometry (CIR-TOF-MS), in conjunction with measurements of NOx, O3 and SOA mass loading. The CIR-TOF-MS measurements allowed approximately 45 time-resolved product ion signals to be detected, which were assigned on the basis of the simulated temporal profiles of the more abundant MCM v3.2 species, and their probable fragmentation patterns. The evaluation studies demonstrate that the MCM v3.2 mechanism provides an acceptable description of β-caryophyllene degradation under the chamber conditions considered, with the temporal evolution of the observables identified above generally being recreated within the uncertainty bounds of key parameters within the mechanism. The studies have highlighted a number of areas of uncertainty or discrepancy, where further investigation would be valuable to help interpret the results of chamber studies and improve detailed mechanistic understanding. These particularly include: (i) quantification of the yield and stability of the secondary ozonide (denoted BCSOZ in MCM v3.2), formed from β-caryophyllene ozonolysis, and elucidation of the details of its further oxidation, including whether the products retain the "ozonide" functionality; (ii) investigation of the impact of NOx on the β-caryophyllene ozonolysis mechanism, in particular its effect on the formation of β-caryophyllinic acid (denoted C137CO2H in MCM v3.2), and elucidation of its formation mechanism; (iii) routine independent identification of β-caryophyllinic acid, and its potentially significant isomer β-nocaryophyllonic acid (denoted C131CO2H in MCM v3.2); (iv) more precise quantification of the primary yield of OH (and other radicals) from β-caryophyllene ozonolysis; (v) quantification of the yields of the first-generation hydroxy nitrates (denoted BCANO3, BCBNO3 and BCCNO3 in MCM v3.2) from the OH-initiated chemistry in the presence of NOx; and (vi) further studies in general to improve the identification and quantification of products formed from both ozonolysis and photo-oxidation, including confirmation of the simulated formation of multifunctional species containing hydroperoxide groups, and their important contribution to SOA under NOx-free conditions.

Raman spectroscopy and X-ray diffraction of lithium niobate at temperatures up to 1300○-4.80pt○C

2005 ◽  
Vol 126 ◽  
pp. 101-105 ◽  
Author(s):  
B. Moulin ◽  
L. Hennet ◽  
D. Thiaudière ◽  
P. Melin ◽  
P. Simon
Keyword(s):  
Raman Spectroscopy ◽  
Lithium Niobate ◽  
X Ray Diffraction ◽  
X Ray

Raman spectroscopy using a gas laser

1965 ◽  
Vol 26 (11) ◽  
pp. 620-626 ◽  
Author(s):  
J.P. Russell
Keyword(s):  
Raman Spectroscopy ◽  
Gas Laser

OBSERVATION OF PRETRANSITIONAL EFFECTS ON THE SHAPE OF THE E2 (17 cm-1 ) OPTICAL MODE IN β-Ag1 BY RAMAN SPECTROSCOPY

1981 ◽  
Vol 42 (C6) ◽  
pp. C6-776-C6-778
Author(s):  
E. Cazzanelli ◽  
A. Fontana ◽  
G. Mariotto ◽  
F. Rocca ◽  
M. P. Fontana
Keyword(s):  
Raman Spectroscopy ◽  
Optical Mode

RAMAN SPECTROSCOPY IN GUIDED OPTICAL WAVES

1983 ◽  
Vol 44 (C10) ◽  
pp. C10-501-C10-503 ◽  
Author(s):  
J. D. Swalen ◽  
J. F. Rabolt
Keyword(s):  
Raman Spectroscopy ◽  
Optical Waves
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