Knowledge Bank

The products of a high frequency electrical discharge in flowing oxygen are frozen out on a fused silica plate maintained near the temperature of liquid helium. The absorption spectra of the collected meterial are studied as a function of layer thickness and of temperature. Spectra are obtained over the range 2200 to 8500A with prism spectrographs, and from 1 to 3.5 microns with a grating spectrometer, using a cooled lead sulfide detector. The absorption spectrum of the condensate from the discharge through oxygen shows some 25 diffuse bands in the range 3500 to 7000A. A few of these bands correspond to bands observed in solid molecular oxygen. In the ultraviolet there is a strong continuous absorption starting at about 3500A and increasing very rapidly toward shorter wavelengths. In the infrared two bands, about $20cm-1$ wide, are observed peaking at 3030 and $3499cm-1$. The band at $3030cm-1$ may be due to $ozone1$, which in the gas phase has an absorption band at $3050cm-1$. In addition there are observed six narrow lines (about $2cm-1$ wide) coming from the fused silica collecting plate. The two strongest lines, at 3364 and $3470cm-1$, show marked broadening and shift by about $10cm-1$ to shorter wavelengths upon warming the plate from liquid helium temperature to room temperature.