Variations in the strength of the infrared forbidden 2328.2 cm-1 fundamental of solid N2 in binary mixtures

We present the 2335-2325 cm(-1) infrared spectra and band positions, profiles and strengths (A values) of solid nitrogen and binary mixtures of N(2) with other molecules at 12 K. The data demonstrate that the strength of the infrared forbidden N(2) fundamental near 2328 cm(-1) is moderately enhanced in the presence of NH(3), strongly enhanced in the presence of H(2)O and very strongly enhanced (by over a factor of 1000) in the presence of CO(2), but is not significantly affected by CO, CH(4), or O(2). The mechanisms for the enhancements in N(2)-NH(3) and N(2)-H(2)O mixtures are fundamentally different from those proposed for N(2)-CO(2) mixtures. In the first case, interactions involving hydrogen-bonding are likely the cause. In the latter, a resonant exchange between the N(2) stretching fundamental and the (18)O = (12)C asymmetric stretch of (18)O(12)C(16)O is indicated. The implications of these results for several astrophysical issues are briefly discussed. (C) 1999 Elsevier Science B.V. All rights reserved.