Preparation of Novel Polyazetes
Abstract
We have investigated several ways to prepare and characterize spectroscopically novel compounds of pure nitrogen:tetrazete N4 and pentazole anion N5. They are of interest to DARPA/AFOSR as potential new high energy density materials (HEDM)s and attractive propellants. Results of earlier, extensive theoretical work (quantum mechanical computations) consistently suggest that tetrazete should be a metastable compound with decomposition barrier of 60 kcal/mol, and it should contain 180 kcal/mol of energy with respect to the two dinitrogen molecules. We have carefully scrutinized several methods to prepare tetrazete and for its subsequent detection we have employed a number of spectroscopic techniques. Microwave, electrical discharge of gaseous nitrogen or fast atom bombardment of solid N2 (at 10K) produces highly reactive neutral and charged nitrogen fragments: N-atoms, N3 radicals and variety of ions. Majority of them recombine among themselves to form back dinitrogen or react will always-present trace amounts of impurities (mostly oxygen atoms) to produce nitrogen oxides. In our experiments we have condensed such mixtures on the low-temperature (5.6-20K) spectroscopic targets (salt windows or Pt-plated cupper). We have observed in IR absorption and Raman spectroscopy many lines characteristic for such compounds. In addition, we have detected absorption lines in the positions that are highly compatible with signals predicted by high-level quantum mechanical calculations for tetrazete. Due to the high symmetry of N4 only one IR absorption should be observable for a pure 14N4 or 15N4 isotopomers, making: the convincing and unambiguous proof difficult on the basis of such observation alone.
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 05, 2004
- Accession Number
- ADA427148
Entities
People
- J. G. Radziszewski
Organizations
- Colorado School of Mines