| Autor: |
McCluskey, M. D., Zhuravlev, K. K. |
| Předmět: |
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| Zdroj: |
Journal of Chemical Physics; 1/22/2002, Vol. 116 Issue 4, p1607, 6p, 1 Chart, 8 Graphs |
| Abstrakt: |
Nitrogen has a complex phase diagram that has presented a formidable challenge to theoretical models. In this study, infrared (IR) spectroscopy has been performed on solid nitrogen at low temperatures and pressures up to 6 GPa. In the &Vegr; phase, two IR absorption peaks were observed that correspond to N–N stretch modes. The presence of two IR-active N[sub 2] vibrons is consistent with a tetragonal structure (P4[sub 3]2[sub 1]2) and is inconsistent with an earlier proposed rhombohedral (R3¯C) structure. The matrix isolation of CO[sub 2] molecules in solid N[sub 2] led to the observation of transverse (ν[sub 2]) vibrational modes, which showed a splitting consistent with the structures of the different N[sub 2] phases. The ν[sub 3] mode of [sup 12]CO[sub 2] and [sup 13]CO[sub 2] molecules was measured as a function of pressure, as well as combination modes. All the vibrational-mode frequencies shifted discontinuously at the critical pressures for N[sub 2] phase transitions. For CO[sub 2] concentrations of 0.1%, phase separation is present at low pressures, but is suppressed for pressures greater than 1 GPa. In summary, these studies have contributed to the knowledge of the N[sub 2] phase diagram and the nature of guest-host interactions in molecular systems. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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