Surface effects on the crystallization of cyclo-1,3,5-trimethylene-2,4,6-trinitramine (RDX) and the consequences for its N K X-ray emission spectrum.

ABSTRACT

Recent studies of the crystallization of cyclotrimethylene-trinitramine (RDX) have shown that the presence of the α- and ß-phases of the compound is sensitive to the substrate when using drop cast crystallization methods. The specific phase has potential consequences for measurements of the nitrogen K X-ray emission spectrum (XES) that were recently reported for this compound using samples crystallized on In metal substrates. We have determined that the crystallization of RDX on a clean In metal substrate starts out completely as the ß-phase but progressively incorporates the α-phase as the film thickens. In addition, we have carried out additional molecular orbital calculations of the N 1s X-ray fluorescence from the valence band, comparing the results expected from the α-and ß- phases. The differences due to the presence of the ß-phase instead of, or in addition to, the α-phase appear to be minimal.