The electronic relaxation of the lowest singlet state of molecular oxygen has been studied in the presence of a number of aliphatic amines. Rate constants have been obtained for quenching by mono-, di-, and trimethyland ethylamines and l,4-diazabicyclo[2.2.2]octane (DABCO). The constants range between 2 X 1051. mol-1 sec-1 (for monomethylamine) and 1.9 X 1071. mol-1 sec-1 (for triethylamine) and display a good correlation with the ionization energy of the quencher. Temperature and pressure dependency studies indicate that no bound intermediate is formed, and the results can be rationalized in terms of a "contact charge-transfer" interaction.
A method of obtaining measurable concentrations of 02(1Ag) and Oz(lXC,+) for kinetic studies has been developed, and a number of reactions of these excited molecules are described. Evidence is presented for simultaneous electronic transitions in a weakly bound complex between two 02(1Ag) molecules resulting in emission bands at 6340 and 7030A. The phenomenon is discussed in terms of the " association theory " of gases.The (0,l) 1 -58 , u band of the (1 A, -3 Z ; ) system is one of the more intense features of the atmospheric " day glow " (the (0,O) 1.27 p band is re-absorbed by the lower atmosphere).l A number of excitation mechanisms have been suggested by Vallance Jones ; 2 however, all of them depend on assumptions about the deactivation crosssections for O@A,) which have not yet been determined. A prominent feature of the " night air glow " is the (0,l
Absolute rates for the intrinsic reaction between Cl atoms and surfaces of P-doped polycrystalline silicon, P-doped Si(100) and As, Sb-doped Si(111) substrates were measured for the first time as a function of dopant concentration (Ne) and substrate temperature in a downstream reaction system. This study clearly shows that when there is no ion bombardment, increasing Ne increases the Si-Cl reaction rate even when silicon is lightly doped (∼1015 cm−3), in contrast to in-discharge studies. Moreover, results showed that crystal orientation influences the Cl-Si reaction more than Ne, for Ne<1020 cm−3. The data are fitted to a modified Arrhenius expression, R=νNγenClT1/2e−E/kT, with R the etch rate and nCl the gas phase Cl concentration. The calculated values of the activation energy E are 4.1–4.7 kcal/mole for all doping levels and crystallographic orientations. Therefore, the doping effect is manifested solely in the preexponential (νNγe) of the Arrhenius expression, and the data qualitatively agree with a charge-transfer mechanism which facilitates chemisorption of chlorine.
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