Spectrophotometric studies of the radiolysis of liquid ammonia

Autor:	J. Belloni, M. O. Delcourt, E. Saito
Rok vydání:	1976
Předmět:	Absorption spectroscopy General Engineering Analytical chemistry chemistry.chemical_element Radiation chemistry Nitrogen Ion Ammonia chemistry.chemical_compound chemistry Radiolysis Azide Physical and Theoretical Chemistry Absorption (chemistry) Nuclear chemistry
Zdroj:	The Journal of Physical Chemistry. 80:1101-1105
ISSN:	1541-5740 0022-3654
DOI:	10.1021/j100551a015
Popis:	The optical absorption spectra of liquid ammonia with or without solutes have been investigated at different doses of ..gamma.. irradiation and different temperatures. The absorption spectrum recorded in initially pure ammonia, at room temperature and doses greater than or equal to 3 x 10/sup 19/ eV ml/sup -1/, corresponds to the azide ion N/sub 3//sup -/ (epsilon/sub 247nm/ 1380 +- 30 M/sup -1/ cm/sup -1/) with a yield G(N/sub 3//sup -/) = 0.05 which completes the material balance of the other products N/sub 2/, H/sub 2/, and N/sub 2/H/sub 4/. At low temperature, the yields are G(H/sub 2/) = 0.61 +- 0.02, G(N/sub 2/) = 0.11 +- 0.01, and G(N/sub 2/H/sub 4/) = 0.305 +- 0.01 within (2-150) x 10/sup 19/ eV ml/sup -1/; and G(H/sub 2/) = 0.74 +- 0.03, G(N/sub 2/) = 0.18 +- 0.01, and G(N/sub 2/H/sub 4/) = 0.26 +- 0.03 in the range (150-500) x 10/sup 19/ eV ml/sup -1/. The spectrum recorded corresponds to the weak absorption of hydrazine (epsilon/sub 247nm/ 2.5 +- 0.5 M/sup -1/ cm/sup -1/), and the azide formation is then negligible, a conclusion which is also expected from the material balance. Solutions of N/sub 2/H/sub 4/ in liquid ammonia irradiatedmore » at room temperature give absorption bands in the uv. These are the sums of the optical densities of N/sub 2/H/sub 4/ which still remains after partial decomposition and the optical densities of a band which increases and is attributed to the azide ion N/sub 3//sup -/ (G(N/sub 3//sup -/) = 0.17 +- 0.02 at low doses). The conclusion is that N/sub 3//sup -/ is formed from a secondary decomposition of N/sub 2/H/sub 4/ by the primary radical /sup T/NH. This mechanism holds in the radiolysis of initially pure ammonia. The azide yields provided by the spectrophotometric method in complement to those of other products are used to deduce some primary radical yields.« less
Databáze:	OpenAIRE
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