Absorption Spectra of Some Active Species¹

Abstract

We have measured the absorption spectrum of the blue solid obtained in the thermal decomposition of UN's as well as those of &, RS (where R represents various organic radicals and (NHjNH),. Films were deposited in a plane aluminized quartz surface kept at liquid nitrogen temperatures and the percentage of absorbed monochromatic light over the range 20,000 to 3000 Á. was measured. The measurements are only semi-quantitative because we were not successful in preventing considerable scattering of the light by the film.

Preparation and Properties of Imido Intermediates (Imidogens)

“…Much of this work involved the decomposition of hydrazoic acid at low pressure, followed by rapid freezing of the reaction products onto a liquid nitrogencooled surface, and the spectroscopic examination of the resulting solid. I n this way, it was found (250,251,253) that if gaseous hydrazoic acid was decomposed thermally a t 1000° and a t a pressure of 0.05-0.2 mm., or photochemically, or by means of a silent electrical discharge, a paramagnetic deep blue solid condensed on the liquid nitrogen-cooled finger. This much discussed condensate, commonly referred to as Rice's Blue Material, turns colorless on warming, the transition temperature varying from -150' t o -125' depending on the amount of deposit on the cold finger and being independent of the matrix material if one is used (84).…”

Photochemistry of a Volcanically Driven Atmosphere on Io: Sulfur and Oxygen Species from a Pele-Type Eruption

“…However, the condensate can appear yellow, green, violet, purple, maroon, or red depending on the percentage of the highly colored metastable molecules like S 3 and S 4 that are initially preserved in the solid; that percentage in turn depends on the composition of the initial vapor, the temperature of the surface upon which the vapor condenses, and the rate of vapor deposition (see Rice and Sparrow 1953, Rice and Ditter 1953, Rice and Ingalls 1959, Meyer and Shumacher 1960, Radford and Rice 1960, Brewer et al 1965, Meyer 1964, 1976. Judging from the absorption spectra of Rice and Ingalls (1959), the purple color of "condensed S 2 " may be due to small amounts of S 4 and S 3 , whose characteristic absorption bands appear to be superimposed upon a "yellow sulfur" (presumably an amorphous mixture of polymeric sulfur and S 8 ) spectrum. This interpretation is not definitive, however, as the observed ∼550-620 nm absorption band in the Rice and Ingalls spectrum of purple sulfur seems to lie at longer wavelengths than the S 4 band.…”

Solid Allotropes of Sulfur

“…Purple Sulfur. S2 vapor condenses on a liquid nitrogen-cooled trap with a purple color (242,244). The color was assigned to the S2 radical.…”