ISSN:
0377-0486
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Physics
Notes:
Raman spectra of polycrystalline normal and three 15N isotopic ammonium nitrates (15NH4NO3, NH4 15NO3 and 15NH4 15NO3) were recorded at various temperatures between 10 and 300 K. Isotopic shifts of both internal and external modes of the ammonium ion relative to isotopic normal NH4NO3 were observed. Various components of the hetero-ionic coupled internal mode (ν3 of the nitrate ion with ν4′ of the ammonium ion) were assigned with more certainty on the basis of the 15N isotopic shifts. Detailed studies of the temperature dependence of one internal mode (ν1) of the NO3 - ion and several external modes were made. The frequency and half band width versus temperature plots for both the internal mode and the external modes of 15NH4NO3 indicate only one crystal structure (phase V) between 10 and 257 K. Comparison of the frequency shifts between various isotopic compounds in the external mode region permitted a more precise assignment of the lattice modes associated with the NH4+ and NO3- ions to be made.
Additional Material:
11 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/jrs.1250231207
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