Absorption Cross-section and Spin Analysis in the Three-photon Process

1973 ◽  
Vol 20 (7) ◽  
pp. 565-576 ◽  
Author(s):  
G.P. Srivastava ◽  
R. Nath ◽  
S.C. Gupta
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Absorption Cross ◽  
Photon Process ◽  
Spin Analysis

scholarly journals Photoelectric absorption cross section of silicon near the bandgap from room temperature to sub-Kelvin temperature

AIP Advances ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 025120
Author(s):  
C. Stanford ◽  
M. J. Wilson ◽  
B. Cabrera ◽  
M. Diamond ◽  
N. A. Kurinsky ◽  
...  
Keyword(s):  
Cross Section ◽  
Absorption Cross Section ◽  
Room Temperature ◽  
Absorption Cross ◽  
Photoelectric Absorption

scholarly journals Ultraviolet Absorption Cross-Sections of Ammonia at Elevated Temperatures for Nonintrusive Quantitative Detection in Combustion Environments

2021 ◽  
pp. 000370282199044
Author(s):  
Wubin Weng ◽  
Shen Li ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Elevated Temperatures ◽  
Uv Absorption ◽  
Energy Utilization ◽  
Quantitative Detection ◽  
Absorption Cross ◽  
Hot Gas

Ammonia (NH3) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH3, accurate in situ detection of NH3 in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH3 in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results, vibrational constants of NH3 were determined and used for the calculation of the absorption cross-section of NH3 at high temperatures above 590 K using the PGOPHER software. The investigated UV spectra covered the range of wavelengths from 190 nm to 230 nm, where spectral structures of the [Formula: see text] transition of NH3 in the umbrella bending mode, v2, were recognized. The absorption cross-section was found to decrease at higher temperatures. For example, the absorption cross-section peak of the (6, 0) vibrational band of NH3 decreases from ∼2 × 10−17 to ∼0.5 × 10−17 cm2/molecule with the increase of temperature from 295 K to 1570 K. Using the obtained absorption cross-section, in situ nonintrusive quantification of NH3 in different hot gas environments was achieved with a detection limit varying from below 10 parts per million (ppm) to around 200 ppm as temperature increased from 295 K to 1570 K. The quantitative measurement was applied to an experimental investigation of NH3 combustion process. The concentrations of NH3 and nitric oxide (NO) in the post flame zone of NH3–methane (CH4)–air premixed flames at different equivalence ratios were measured.

scholarly journals Solvent effects on the three-photon absorption cross-section of a highly conjugated fluorene derivative

2006 ◽  
Vol 125 (16) ◽  
pp. 161102 ◽  
Author(s):  
Ion Cohanoschi ◽  
Kevin D. Belfield ◽  
Carlos Toro ◽  
Florencio E. Hernández
Keyword(s):  
Cross Section ◽  
Solvent Effects ◽  
Absorption Cross Section ◽  
Photon Absorption ◽  
Absorption Cross ◽  
Fluorene Derivative
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