Product distributions of the acetylene + atomic oxygen and HCCO (ketenyl) + atomic hydrogen reactions. Rate constant of methylene(.apprx.X3B1) + atomic hydrogen

1992 ◽  
Vol 96 (24) ◽  
pp. 9810-9816 ◽  
Author(s):  
Werner Boullart ◽  
Jozef Peeters
Keyword(s):  
Rate Constant ◽  
Atomic Hydrogen ◽  
Atomic Oxygen ◽  
Product Distributions ◽  
Hydrogen Reactions

Measurement of rate constant for quenching CO 2 (0110) by atomic oxygen at low temperatures: reassessment of the population of CO 2 (0110) and the CO 2 15-μm emission cooling in the lower thermosphere

2003 ◽  
Author(s):  
Gustav M. Shved ◽  
Lyudmila E. Khvorostovskaya ◽  
Igor Y. Potekhin ◽  
Vladimir P. Ogibalov ◽  
Tatyana V. Uzyukova
Keyword(s):  
Rate Constant ◽  
Low Temperatures ◽  
Atomic Oxygen ◽  
Lower Thermosphere

Direct rate constant measurements for atomic hydrogen + methane .fwdarw. methyl + hydrogen, 897-1729 K, using the flash photolysis-shock tube technique

1991 ◽  
Vol 95 (2) ◽  
pp. 674-681 ◽  
Author(s):  
M. J. Rabinowitz ◽  
J. W. Sutherland ◽  
P. M. Patterson ◽  
R. B. Klemm
Keyword(s):  
Shock Tube ◽  
Rate Constant ◽  
Atomic Hydrogen ◽  
Flash Photolysis

scholarly journals New insights into OH airglow modelling to derive night-time atomic oxygen and atomic hydrogen in the mesopause region

2018 ◽  
Author(s):  
Tilo Fytterer ◽  
Christian von Savigny ◽  
Martin Mlynczak ◽  
Miriam Sinnhuber
Keyword(s):  
Atomic Hydrogen ◽  
Atomic Oxygen ◽  
Box Model ◽  
Satellite Measurements ◽  
Night Time ◽  
Vibrationally Excited ◽  
Mesopause Region ◽  
Airglow Emissions ◽  
Instrument Configuration ◽  
Best Fit

Abstract. An OH airglow model was developed to derive night-time atomic oxygen (O(3P)) and atomic hydrogen (H) from satellite OH airglow observations in the mesopause region (~ 75–100 km). The OH airglow model is based on the zero dimensional box model CAABA/MECCA-3.72f and was empirically adjusted to fit four different OH airglow emissions observed by the satellite/instrument configuration TIMED/SABER at 2.0 μm and at 1.6 μm as well as measurements by ENVISAT/SCIAMACHY of the transitions OH(6-2) and OH(3-1). Comparisons between the Best fit model obtained here and the satellite measurements suggest that deactivation of vibrationally excited OH(v) via OH(v ≥ 7) + O2 might favour relaxation to OH(v' ≤ 5) + O2 by multi-quantum quenching. It is further indicated that the deactivation pathway to OH(v' = v − 5) + O2 dominates. The results also provide general support of the recently proposed mechanism OH(v) + O(3P) → OH(0 ≤ v' ≤ v − 5) + O(1D) but suggest slower rates of OH(v = 7,6,5) + O(3P). Additionally, deactivation to OH(v' = v − 5) + O(1D) might be preferred. The profiles of O(3P) and H derived here are plausible between 80 km and 95  km. The values of O(3P) obtained in this study agree with the corresponding TIMED/SABER values between 80 km and 85 km, but are larger from 85 to 95 km due to different relaxation assumptions of OH(v) + O(3P). The H profile found here is generally larger than TIMED/SABER H by about 30–35 % from 80 to 95 km, which might be attributed to too high O3 night-time values.

scholarly journals Mariner 6: Ultraviolet spectrum of Mars upper atmosphere

1971 ◽  
Vol 40 ◽  
pp. 253-256 ◽  
Author(s):  
C. A. Barth ◽  
W. G. Fastie ◽  
C. W. Hord ◽  
J. B. Pearce ◽  
K. K. Kelly ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Spectral Region ◽  
Atomic Hydrogen ◽  
Atomic Oxygen ◽  
Ultraviolet Spectrum ◽  
Upper Atmosphere

Emission features from ionized carbon dioxide and carbon monoxide were measured in the 1900- to 4300-Å spectral region. The Lyman-α 1216-Å line of atomic hydrogen and the 1304-, 1356-, and 2972-Å lines of atomic oxygen were observed.

scholarly journals Water-soluble cavitands promote hydrolyses of long-chain diesters

2016 ◽  
Vol 113 (33) ◽  
pp. 9199-9203 ◽  
Author(s):  
Qixun Shi ◽  
Matthew P. Mower ◽  
Donna G. Blackmond ◽  
Julius Rebek
Keyword(s):  
Rate Constant ◽  
Hydrocarbon Chain ◽  
Ester Group ◽  
Water Soluble ◽  
Hydrolysis Rate ◽  
Bulk Solution ◽  
Confined Space ◽  
Selective Hydrolysis ◽  
Product Distributions ◽  
Long Chain

Water-soluble, deep cavitands serve as chaperones of long-chain diesters for their selective hydrolysis in aqueous solution. The cavitands bind the diesters in rapidly exchanging, folded J-shape conformations that bury the hydrocarbon chain and expose each ester group in turn to the aqueous medium. The acid hydrolyses in the presence of the cavitand result in enhanced yields of monoacid monoester products. Product distributions indicate a two- to fourfold relative decrease in the hydrolysis rate constant of the second ester caused by the confined space in the cavitand. The rate constant for the first acid hydrolysis step is enhanced approximately 10-fold in the presence of the cavitand, compared with control reactions of the molecules in bulk solution. Hydrolysis under basic conditions (saponification) with the cavitand gave >90% yields of the corresponding monoesters. Under basic conditions the cavitand complex of the monoanion precipitates from solution and prevents further reaction.

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