Low Temperature Physics: 32, 1050 (2006); https://doi.org/10.1063/1.2389012 (17 pages)
Физика Низких Температур: Том 32, Выпуск 11 (Ноябрь 2006), c. 1382-1401    ( к оглавлению , назад )

Fourier transform infrared studies of the N2-O2 binary system

M. Minenko and H.-J. Jodl

TU Kaiserslautern, Department of Physics, Erwin Schrdinger Str., Kaiserslautern 67663, Germany
E-mail: jodl@physik.uni-kl.de

Received May 26, 2006


Solid solutions (N2)x(O2)1–x have been investigated by infrared absorption measurements mainly in the O2 and N2 stretching regions, between 60–10 K, completing former similar studies by Raman scattering. We produced thermodynamically stable samples by a careful thermal treatment, followed by cooling/heating cycles over weeks, during which we took spectra. From fingerprints in infrared spectra we deduce phase transition lines, solubility lines and suggest a refined, improved T–x% phase diagram with respect to inconsistencies between those in literature. Spectra of N2–O2 mixtures are pretty complex but referring to known spectra of pure systems N2 or O2 we were able to assign and interpret broad (~100 cm–1) phonon side bands to fundamentals and electronic transition (O2) depending on actual temperature and concentration. Narrow features in spectra (<10 cm–1) were attributed to the vibron DOS of N2 or O2, whose bandwidth, band shape and intensity are different and characteristic for each phase. Differences between pure and mixed systems were pointed out. Matrix isolation technique (2 ppm of CO) was used to probe our mixture.

81.30.-t - Phase diagrams and microstructures developed by solidification and solid-solid phase transformations (see also 64.70.Kb Solid-solid transitions)
64.70.Kb - Solid-solid transitions (see also 61.50.Ks Crystallographic aspects of phase transformations; pressure effects; 75.30.Kz and 77.80.Bh for magnetic and ferroelectric transitions, respectively; for material science aspects, see 81.30.-t)
64.75.+g - Solubility, segregation, and mixing; phase separation (see also 82.60.Lf Thermodynamics of solutions; 47.51.+a Mixing in fluid dynamics)
78.30.-j - Infrared and Raman spectra (for vibrational states in crystals and disordered systems, see 63.20.-e and 63.50.+x respectively)
63.20.Ls - Phonon interactions with other quasiparticles

Ключевые слова: infrared absorbtion, Fourier-transform infrared technique, vibrational and exitonic region.