Calculation of Einstein A Coefficients and Oscillator Strengths for the A 2A(1) - X 2B(1) Transition of NH(2)
Abstract
The NH2 radical plays an important role in the decomposition chemistry of solid propellants, in particular nitramines. Additives which produce large amounts of NH2 are also known to have burn rate acceleration effects on HMX based propellants, probably due to the reduction of NO by NH2. We believe that these or similar additives may also produce important ignition enhancement effects and are planning studies in this area. In order to spectroscopically probe NH2 in these studies, the strength of individual rovibronic transitions in the molecule's best known electronic transition, A 2A(1) - X 2B(1), must be known. Until recently, however, such information was available for only two lines and these were not precisely known. Recently, a method was presented (see References 2 and 3) whereby Einstein coefficients and oscillator strengths may be calculated for the individual lines. The calculation is straightforward, but not readily transparent to the uninitiated. We therefore promised in Reference 3 to make this monograph, which provides example calculations, available. Methods of identifying transitions involving perturbed levels, for which the calculation may not work well, are first discussed. Then an example calculation of a radiative lifetime for a vibrational level in the A state and calculation of the Einstein coefficients and oscillator strengths for two rovibrational lines are given.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1989
- Accession Number
- ADA213837
Entities
People
- William R. Anderson
Organizations
- Ballistic Research Laboratory