On the possibility of detecting tetraazatetrahedrane (N4) in liquid or solid nitrogen by Fourier transform Raman spectroscopy

Abstract

AbstractThe detection limit of N4 (at Td and D2h symmetry) by the Fourier transform (FT) Raman technique was determined in liquid and solid nitrogen using a modified commercial FT‐Raman spectrometer. The detection limit was determined by combining experimental signal strength and noise levels of N2 in liquid and solid nitrogen with ab initio quantum mechanical (QM) calculations of the Raman intensities of N2 and N4 (Td and D2h). The QM calculations were performed at the B3LYP/6–311G(d) level. The detection limit was found to be 34 ppm of N4(Td) in N2(liq) and 80 ppm in N2(solid), using an 8 h measurement time and a laser power of 1000 mW. The paper also reports calculated Raman spectra of N4 (Td and D2h) at the B3LYP/6–311G(d) level and a new harmonic wavenumber scaling factor, s = 0.953447, for nitrogen‐containing molecules at the B3LYP/6–311G(d) level. The Raman spectrum of N4(Td) consists of three lines, at 728.35, 938.93 and 1321.58 cm−1, with Raman scattering activities of 17.5, 36.2 and 30.0 Å4 u−1, respectively. Copyright © 2001 John Wiley & Sons, Ltd.