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

✍ Scribed by Henric Östmark; Olli Launila; Sara Wallin; Rolf Tryman

• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 168 KB
• Volume: 32
• Category: Article
• ISSN: 0377-0486
• DOI: 10.1002/jrs.686

✦ Synopsis

The detection limit of N 4 (at T d and D 2h 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 N 2 in liquid and solid nitrogen with ab initio quantum mechanical (QM) calculations of the Raman intensities of N 2 and N 4 (T d and D 2h ). The QM calculations were performed at the B3LYP/6-311G(d) level. The detection limit was found to be 34 ppm of N 4 .T d / in N 2 (liq) and 80 ppm in N 2 (solid), using an 8 h measurement time and a laser power of 1000 mW. The paper also reports calculated Raman spectra of N 4 (T d and D 2h ) 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 N 4 .T d / 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.