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A photo-ionization detector for vibrationally excited nitrogen (N2*) has been used to obtain the rate of quenching of N2* by atomic oxygen in the temperature range 300ø-723 øK. The quenching rate coefficient was found to be 3.2 X 10 -•5 cm 3 s -• at 300øK, 1.3 X 10 -•4 cm 3 s -• at 463øK, 2.7 X 10 -•4 cm a s -• at 633øK, and 4.0 X 10 -• cm a s -• at 723øK. These rate coefficients are extremely large compared with the expected values for a conventional vibrational-translational (VT) energy transfer process in this temperature range. They are also large compared with the predictions of the vibrational relaxation theory developed by Fisher and Bauer for the N2-O system based upon crossing of covalent potential energy curves. The measured coefficients combined with higher temperature data obtained elsewhere with different experimental methods indicate that the VT process in the N2-O system is anomalously efficient over the range 300ø-4500øK and has only a moderate temperature dependence. This result has important consequences in the upper atmosphere, where the effect of an efficient VT process involving N2 and O is to hold the atmospheric N2 vibrational temperature at or very near the ambient kinetic temperature, in agreement with the results of recent rocket probe experiments. Processes that produce and quench vibrationally excited nitrogen (N•,) have attracted considerable attention in recent years because of their potential impact on the physics and chemistry of the earth's upper atmosphere. The Ns* is produced at high altitudes by collisions with ionospheric and auroral electrons, in exothermic chemical reactions, and in energy transfer processes involving other excited atmospheric species [Walker et al., 1969]. Once it is produced, the Ns* can transfer energy to infrared-emitting molecules such as COs, CO, and NO that contribute to the airglow. Vibrational excitation has also been found experimentally [Schmehekopfet al., 1968] to accelerate the rate of the reaction of O + with Ns to form NO + , an important ion-molecule reaction in the ionosphere. Until very recently, information on atmospheric production and loss processes involving Ns* has been almost

: Since their introduction in the early 1980s, there have been a number of Ðeld studies conducted to assess the e †ects of sulfonylurea herbicides on nontarget plants (i.e. plants not labeled for use). In these studies a wide variety of plant response assessment techniques have been used to measure e †ects on nontarget plants. This paper examines the relationship of short-term plant response measurements to plant productivity measurements such as yield or quality. Whether short-term plant response measurements have a practical degree of accuracy and precision appropriate for hazard assessment on non-target plants from sulfonylureas is discussed. A comprehensive review of published literature and unpublished Ðeld studies of the e †ects of sulfonylureas on the yield and quality of non-target plant species is reported. When this information is coupled with exposure factors and environmental fate characteristics, the risks to nontarget plants from sulfonylureas are similar to those from other herbicides used at higher application rates.

Absolute photoionization and absorption coefficients of CO have been measured in the 600 to 1 000 Å region using a 1-meter Seya-Namioka scanning vacuum ultraviolet monochromator. The Hopfield helium continuum background source was used with photoelectric detection of the dispersed light. Numerous peaks were observed at wavelengths that were found to agree well with those of a higher-resolution photographic absorption spectrum. Two well-defined ionization continua followed the first and second ionization potential. Continua due to dissociation were also observed. Efficiencies for preionization of the progressions and Rydberg bands of the sharp and of the diffuse series converging to the B2Σ+ state were estimated. Total fluorescence emission associated with the A2Π state of CO+ was measured, and the onset was found to contain vibrational structure.