Metastability in Molecules
Abstract
Pentazole (HN5) has the fingerprints of a metastable molecule since even though it offers a perfectly logical, even aromatic electronic structure, it is unknown experimentally. We subjected HN5 to theoretical analysis. At the correlated level we find that for the reaction, 2HN5 - 5N2 + H2 DeltaE is -129.1 kcal/mol resulting in an I(sub sp) of 346 as a monopropellant. Considering that derivatives of the basic structure should be made to stabilize the pentazole ring, we can consider some which will be quite energetic (examples include nitropentazole, and a bipentazole analogous to biphenyl and possibly a dinitramine pentazole (O2N)N-N5, and numerous metal, MN5 structures, where M could be Li e.g.. The prospects for actually making and using pentazoles is promising. Several recent methodology developments have been accomplished in this project. These methods, mostly unique to our effort, make it possible to perform high-level, accurate correlated calculations on much larger potential metastable species than was previously possible. These include the following: (1) Direct product decomposition approach to the full use of Abelian symmetry in coupled-cluster and MBPT applications. (2) Restricted open-shell Hartree Fock (ROHF) based CC and MBPT methods. (3) Analytical first derivatives (i.e. gradient) for open-shell CC/MBPT methods.... Metastable, Molecules, HEDM.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 05, 1993
- Accession Number
- ADA264344
Entities
People
- Rodney J. Bartlett
Organizations
- University of Florida