Molecular Dynamic Simulation of Cyclotetramethylene Tetranitramine/1, l-Diamino-2. 2-Dinitroethylene Co-crystal Explosive.

Six models of cyclotetramethylene tetranitramine (HMX)/1, 1-diamino-2. 2-dinitroethylene (FOX-7) co-crystal were constructed based on the main growth faces of HMX crystal and the hydrogen bond rules of co-crystal formation. The probability of HMX/FOX-7 co-crystal formation was investigated using the molecular dynamics (MD) method. The distributions of bond length, angle, and dihedral angle were calculated during MD. As a result, a serious distortion was observed. The radical distribution function (RDF) was used to study the acting force between oxygen atoms in HMX and hydrogen atoms in FOX-7 or hydrogen atoms in HMX and oxygen atoms in FOX-7, which indicates that there are strong hydrogen bonds and Van Der Waals forces between HMX and FOX-7. Binding energies and X-ray powder diffraction (XRD) were calculated on the basis of the final HMX/FOX-7 co-crystal structure. The results show that the orders of binding energies of the six co-crystal models are Eb (020) > Eb (100) > Eb (randomness) > Eb (11̄1) > Eb(10̄2) > Eb (011), and the XRD peaks of six co-crystal models are quite different from pure HMX or FOX-7. In view of the research on crystal growth morphology, binding energy and RDF, the model of HMX molecular substituted by FOX-7 on the surface (11Six models of cyclotetramethylene tetranitramine (HMX)/l , l-diamino-2. 2-dinitroethylene (FOX-7) co-crystal were constructed based on the main growth faces of HMX crystal and the hydrogen bond rules of co-crystal formation. The probability of HMX/FOX-7 co-crystal formation was investigated using the molecular dynamics (MD) method. The distributions of bond length, angle, and dihedral angle were calculated during MD. As a result, a serious distortion was observed. The radical distribution function (RDF) was used to study the acting force between oxygen atoms in HMX and hydrogen atoms in FOX-7 or hydrogen atoms in HMX and oxygen atoms in FOX-7 , which indicates that there are strong hydrogen bonds and Van Der Waals forces between HMX and FOX-7. Binding energies and X-ray powder diffraction (XRD) were calculated on the basis of the final HMX/FOX-7 co-crystal structure. The results show that the orders of binding energies of the six co-crystal models are Eb (020) > Eb (100) > Eb (randomness) > Eb (ll̄l) > Eb(10̄2) > Eb (011), and the XRD peaks of six co-crystal models are quite different from pure HMX or FOX-7. In view of the research on crystal growth morphology, binding energy and RDF, the model of HMX molecular substituted by FOX-7 on the surface (11̄1) of HMX is more liable to form. 1) of HMX is more liable to form. [ABSTRACT FROM AUTHOR]