Picosecond Optical Grating Calorimetry of Singlet Methylene in Benzene

1995 ◽  
Vol 117 (24) ◽  
pp. 6635-6636 ◽  
Author(s):  
M. I. Khan ◽  
Joshua L. Goodman
Keyword(s):  
Optical Grating ◽  
Singlet Methylene

Singlet Methylene Removal Rate Constants from the (0,1,0) Vibrational Level: Enhancement via Complex-Mediated Vibrational Relaxation

2001 ◽  
Vol 215 (6) ◽  
Author(s):  
M.A. Buntine ◽  
G.J. Gutsche ◽  
W.S. Staker ◽  
M.W. Heaven ◽  
K.D. King ◽  
...  
Keyword(s):  
Vibrational Level ◽  
Rate Constants ◽  
Vibrational Relaxation ◽  
Flash Photolysis ◽  
Laser Flash Photolysis ◽  
Removal Rate ◽  
Laser Flash ◽  
Laser Absorption ◽  
Photolysis Laser ◽  
Singlet Methylene

The technique of laser flash photolysis/laser absorption has been used to obtain absolute removal rate constants for singlet methylene,

scholarly journals Analysis of Dielectric Waveguide Grating and Fabry–Perot Modes in Elastic Grating in Optical Detection of Ultrasound

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4081
Author(s):  
Suejit Pechprasarn ◽  
Chayanisa Sukkasem ◽  
Phitsini Suvarnaphaet
Keyword(s):  
Optical Properties ◽  
Dielectric Waveguide ◽  
Figure Of Merit ◽  
Pressure Range ◽  
Optical Filter ◽  
Grating Period ◽  
Wave Mode ◽  
Waveguide Grating ◽  
Fabry Perot ◽  
Optical Grating

In our previous work, we have demonstrated that dielectric elastic grating can support Fabry–Perot modes and provide embedded optical interferometry to measure ultrasonic pressure. The Fabry–Perot modes inside the grating provide an enhancement in sensitivity and figure of merit compared to thin film-based Fabry–Perot structures. Here, in this paper, we propose a theoretical framework to explain that the elastic grating also supports dielectric waveguide grating mode, in which optical grating parameters control the excitation of the two modes. The optical properties of the two modes, including coupling conditions and loss mechanisms, are discussed. The proposed grating has the grating period in micron scale, which is shorter than the wavelength of the incident ultrasound leading to an ultrasonic scattering. The gap regions in the grating allow the elastic grating thickness to be compressed by the incident ultrasound and coupled to a surface acoustic wave mode. The thickness compression can be measured using an embedded interferometer through one of the optical guided modes. The dielectric waveguide grating is a narrow bandpass optical filter enabling an ultrasensitive mode to sense changes in optical displacement. This enhancement in mechanical and optical properties gives rise to a broader detectable pressure range and figure of merit in ultrasonic detection; the detectable pressure range and figure of merit can be enhanced by 2.7 times and 23 times, respectively, compared to conventional Fabry–Perot structures.

Ab Initio Study of the Stability of the Ylide-like Intermediate Methyleneoxonium in the Reaction between Singlet Methylene and Water

1996 ◽  
Vol 118 (23) ◽  
pp. 5408-5411 ◽  
Author(s):  
Carlos Gonzalez ◽  
Albeiro Restrepo-Cossio ◽  
Manuel Márquez ◽  
Kenneth B. Wiberg
Keyword(s):  
Ab Initio ◽  
Ab Initio Study ◽  
The Stability ◽  
Singlet Methylene

Methylene. III. Gas phase reactions with 1-chloropropane

1969 ◽  
Vol 312 (1509) ◽  
pp. 141-161 ◽  
Keyword(s):  
Gas Phase ◽  
Rate Constants ◽  
Hydrogen Abstraction ◽  
The Other ◽  
Gas Phase Reactions ◽  
Other Hand ◽  
Chlorine Substituent ◽  
High Degree ◽  
Singlet Methylene

The work described in this and the following paper is a continuation of that in parts I and II, devoted to elucidation of the mechanism of the reactions of methylene with chloroalkanes, with particular reference to the reactivities of singlet and triplet methylene in abstraction and insertion processes. The products of the reaction between methylene, prepared by the photolysis of ketene, and 1-chloropropane have been identified and estimated and their dependence on reactant pressures, photolysing wavelength and presence of foreign gases (oxygen and carbon mon­oxide) has been investigated. Both insertion and abstraction mechanisms contribute significantly to the over-all reaction, insertion being relatively much more important than with chloroethane. This type of process appears to be confined to singlet methylene. If, as seems likely, there is no insertion into C—Cl bonds under our conditions (see part IV), insertion into C2—H and C3—H bonds occurs in statistical ratio, approximately. On the other hand, the chlorine substituent reduces the probability of insertion into C—H bonds in its vicinity. As in the chloroethane system, both species of methylene show a high degree of selectivity in their abstraction reactions. We find that k S Cl / k S H >7.7, k T Cl / k T H < 0.14, where the k ’s are rate constants for abstraction, and the super- and subscripts indicate the species of methylene and the type of atom abstracted, respectively. Triplet methylene is discriminating in hydrogen abstraction from 1-C 3 H 7 Cl, the overall rates for atoms attached to C1, C2, C3 being in the ratios 2.63:1:0.

Quantitative FM Spectroscopy at High Temperatures: The Detection of 1CH2 behind Shock Waves

2000 ◽  
Vol 214 (12) ◽  
Author(s):  
G. Friedrichs ◽  
H.Gg. Wagner
Keyword(s):  
High Temperature ◽  
Shock Waves ◽  
High Temperatures ◽  
Frequency Modulation ◽  
Modulation Frequency ◽  
Optical Power ◽  
Time Resolved ◽  
Signal Conversion ◽  
High Modulation ◽  
Singlet Methylene

The technique of time resolved frequency modulation (FM) spectroscopy has been shown to provide a very sensitive means to detect small radicals behind shock waves. Features of high temperature FM spectroscopy behind shock waves will be discussed and a general signal conversion procedure to carry out quantitative concentration measurements will be presented.Using a high modulation frequency, a high modulation index and high total optical power, singlet methylene radicals (α

Singlet methylene in the photolysis of mercury-ketene-butene systems

1968 ◽  
Vol 72 (10) ◽  
pp. 3705-3706 ◽  
Author(s):  
Derek C. Montague ◽  
F. S. Rowland
Keyword(s):  
Singlet Methylene

ChemInform Abstract: Reactivity and Intersystem Crossing of Singlet Methylene in Solution.

ChemInform ◽  
1987 ◽  
Vol 18 (32) ◽  
Author(s):  
N. J. TURRO ◽  
Y. CHA ◽  
I. R. GOULD
Keyword(s):  
Intersystem Crossing ◽  
Singlet Methylene

The Principle and Structure of Novel High-Precision Linear Time Grating Displacement Sensors

2012 ◽  
Vol 236-237 ◽  
pp. 1216-1221
Author(s):  
Dong Lin Peng ◽  
Ji Sen Yang ◽  
Xi Hou Chen ◽  
Zi Ran Chen
Keyword(s):  
Linear Time ◽  
Theoretical Concept ◽  
Electrical Machine ◽  
Displacement Sensors ◽  
Time Space ◽  
Optical Grating ◽  
Testing Technology ◽  
Measurement And Testing ◽  
Space Coordinate ◽  
Physical And Mathematical Models

The existing grating type sensors such as optical grating sensor, have long been designed to rely on the precise mechanical space division technology, which is hard to develop without heavy investment. A theoretical concept, time-space coordinate transformation, was presented to realize measuring spatial displacement with time difference. Similar to the principle of circular time grating based on rotating electrical machine, linear time grating is designed based on the principle of linear motor, with which the physical and mathematical models of linear time grating are established. Based on these models linear time grating mechanical structure is designed, which has commercialization value. The resolution of linear time grating can achieve 0.1μm tested by National Institute of Measurement and Testing Technology.

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