The determination of the rotational temperature in nitrogen using measurements of electron beam-induced fluorescence, depends upon the formulation employed to calculate the temperature from the spectral data as well as upon the resolution of the spectrometer. The errors introduced in the measurements by the use of the prevalent forced semilogarithmic data analysis and by incomplete resolution of the rotational lines are examined and evaluated. An alternative method of data analysis is presented. When the errors are accounted for, the dependence of the measured temperature on the number of rotational lines used in the analysis is eliminated, and the apparent rotational temperature becomes less dependent upon the gas density and the true gas temperature.

Photochemical Primary Processes of Xanthene Dyes. II. Investigations of the Influence of Anionic Micelles on the Primary Processes of Selenopyronine by Flash Excitation In aqueous solutions containing anionic micelles, the dye cations of selenopyronine are present at the micellar surface. If the concentration of the dye ions is much lower than the concentration of micelles, only monomolecular triplet decay (k1aM = 2 · 10−3s−1) is observed. Under these conditions, the half‐oxidized and half‐reduced form of selenopyronin is not formed. If the concentration of the dye ions is much higher than the concentration of micelles, two or more dye ions are present at every micelle, and a fast bimolecular decay of the triplet state during the flash is observed. The quenching of the triplet state with p‐benzoquinone (k7aM = 1,9 · 109 l/mol s), DABCO (k10aM = 1,6 · 107 l/mol s) and EDTA (k11aM = 1,3 · 105 l/mol s) and the decay processes of the half‐reduced and half‐oxidized form in the micellar solution are investigated.

Photochemical Primary Processes of Xanthene Dyes. I. Investigations of the Primary Processes of Selenopyronine by Flash Excitation The triplet‐state of selenopyronine absorbs light in the whole investigated spectral range (λmax = 400 nm, 480 nm, 690 nm). As results of the bimolecular triplet decay a half‐reduced (λmax = 430 nm) and a half‐oxidized (λmax = 475 nm) form of the dye are observed. p‐Benzoquinone quenches the triplet‐state (k7 = 1,5 · 109 l/mol s) and the results are the half‐oxidized form and the p‐benzosemiquinone ion. For these two products different decay processes exist. The reducing agents DABCO, EDTA and Hydroquinone also quench the triplet state (k10 = 1,2 · 106 l/mol s, k11 = 1,0 · 106 l/mol s, k12 = 1,0 · 109 l/mol s) and as result the half‐reduced form is observed. Measurements with thiopyronine give analogous results, which are in good agreement with investigations published in the literature.

Based on recent studies, the effect of re-excited ions in the emission of electron beam induced fluorescence in nitrogen has been estimated. These effects are included in the formulation of a composite model describing the excitation and de-excitation of nitrogen by an electron beam. The shortcomings of previous models, namely the dependence of the measured temperature on the true gas temperature as well as the gas density, are almost completely eliminated in the range of temperatures and densities covered by the available data. Nomenclature A = collision cross-section between a ground state ion and an exciting electron B -density coefficient C = mean thermal speed of the molecular ions D = debye length in plasma or dipole transitions F = excitation function of the neutral molecules or ions by a primary beam electron G = transition factor of ground state molecules or ions / = intensity of the rotational line in the rotational spectrum of nitrogen K = quantum number of the rotational line of the excited ion before emission L = distance required for an ionizing collision between a primary beam electron and the neutral gas molecules P = overall transition probability of the ground state molecules or ions Q = quadrupole transition T = temperature of the gas b = intercept of the least squares line fit d = diameter of the electron beam n = number density of the gas molecules, ions, or plasma electrons p = gas pressure oc = a proportionality constant = exponent relating the plasma electron number density to the gas molecule number density y = a proportionality constant 6 = characteristic rotational temperature of the gas v = frequency of the rotational line p = gas density in grams per cubic centimeter a = standard error in the measurement of the average temperature Subscripts D = dipole transition / = ions K =• quantum number Q = quadrupole transition e -plasma electron r = rotational mode of the molecules

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