Edward C. Y. Inn

Absorption Coefficient of Ozone in the Ultraviolet and Visible Regions

As an extension to previous measurements on absorption coefficients-of ozone in the vacuum ultraviolet, similar measurements have been made in the near ultraviolet from the overlapping region at 2000A up to about 3500A and in the visible from about 4000–7500A. The absorption coefficient measurements were made using ozone gas obtained by direct vaporization from liquid ozone of high purity (at least 90–95 percent) and the optical densities measured with a Cary recording spectrophotometer with a 10-cm quartz absorption dell. The method is essentially different from those used by previous investigators, e.g., photoelectric detectors instead of photographic, pure ozone instead of ozonized oxygen, and the absorption cell located at the exit slit instead of between the light source and entrance slit. The absorption coefficients obtained are somewhat consistently lower than those previously reported by Ny and Choong, hitherto considered the most reliable.

Intensity Measurements in the Vacuum Ultraviolet

Intensities of dispersed radiation in the region 500–3000A were measured with a compensated thermocouple mounted at the exit slit of a one-meter, normal incidence, vacuum monochromator. With 1-mm slits (17A band width), HeI at λ584 was found to be 0.025 microwatt over the exit slit. With a 1P21 tube coated with sodium salicylate and using 50-micron slits, the relative intensities of the first four members of the principal series of HeI at λ584, λ537, λ522, and λ516 were measured. The H2 spectrum from 850 to 3000A was also obtained with the thermocouple. The relative quantum efficiency of sodium salicylate was found to be constant in this spectral region and about 15 percent lower at λ584. Some of these measurements were made possible by a great increase of grating efficiency after an unintentional coating of the grating with a layer of evaporated platinum.

Charge transfer between He+ and N2

Abstract Emission of several bands of the second negative system of N 2 + has been observed in mixtures of N 2 with afterglowing He. The emission follows charge transfer between He + and N 2 ; the relevant rate coefficient is estimated to be about (1 − 0.05) × 10 −9 cm 3 sec −1 at thermal energy. It is predicted that the radiative sequence is a source of an U.V. airglow in the region of the maximum of the He + layer in the upper atmosphere. A conservative estimate of the airglow emission rate of the (3, 9) band of the second negative system of N 2 + is calculated to be about 5 R.

Intensity measurements of the 1 μ CO2 bands

Abstract The quantitative intensity of the weak CO2 triad in the 1 μ spectral region has been measured. Integrated R-branch intensities were obtained by using pressure broadening techniques with absorbing paths up to 4·8 km-atm. The R-branch intensities for the transitions 20°3«00°0, 12°3«00°0, and 04°3«00°0 are 1·27, 3·50, and 0·59 cm−1 km−1 atm−1 S.T.P., respectively. Intensities and half-widths of the J4 through J22 lines in the P-branch of the 12°3«00°0 transition have been determined.

Intensity of the 1·6 μ bands of CO2

Quantitative measurements of intensity and half-width have been made for over 30 lines in each of the C12O162 bands of the 1·6 μ tetrad. The total band intensities, derived from the line intensity measurements, for the (30°1)I, (30°1)II, (30°1)III, and (30°1)IV bands are 127, 1050, 1070, and 122 cm-1 km-1 atm-1 STP, respect ively. The observed rotational line intensity distribution of the (30°1)III band was found to depart slightly from the Boltzmann distribution. A satisfactory fit to the observed distribution was obtained by applying a weak vibration- rotation interaction. The widths of the lines of the (30°1)IV band are found to be 50 per cent larger than those of the other members of this tetrad.

Lyman-band fluorescence intensity vs H 2 pressure

The fluorescence intensity of the H2 Lyman bands (B1Σu+→X1Σg+) excited by the argon 1066 A line was found to have a linear dependence on H2 pressure at pressures less than 10−3 torr. The fluorescence from the HD that occurs naturally in the hydrogen was found to be similarly dependent on the HD partial pressure.

Secondary ionization processes due to proton bombardment in aurorae.

Abstract It is suggested that excited hydrogen atoms arising from the deposition of protons in the upper atmosphere, as inferred from the observed auroral Hα emission, may provide an important secondary source of auroral ionization. The mechanisms discussed are photoionization of O 2 by HLβ and collisions of the second kind between excited hydrogen atoms and O 2 .