Any final design should be based onAbstract: The structures and intermolecular interactions for octahydro-1, 3, 5, 7-tetranitro-1, 3, 5, 7-tetrazocine (HMX)/ N, N-dimethylformamide (DMF) solvate have been investigated through quantum chemistry calculations and molecular dynamics (MD) simulations. It must be realised that many material properties (such as toughness) vary between wide limits depending on composition and previous treatment. Our material and raw materials testing especially offer a comprehensive analysis of the strength and effectiveness of various types of samples including metal, polymer and more.reproduced by permission the same data source was used for the material property and process attribute charts. It could be trash samples or premium samples, raw materials testing or chemical composition analysis, our laboratory has the capacity and capability to run a huge variety of testing and analysis.Results reveal that C—H…O hydrogen bond interactions exist between components. Geometrical optimizations at the level of MP2/6-31G * are performed for all the possible homodimers and heterodimers between α-HMX and DMF. This explains why all HMX molecules present α-form in the polymorphic forms of HMX/DMF solvate. Theoretical calculations at the MP2/6-31G * level also indicate that the α-HMX is more stable than β-HMX in DMF solution.It includes the chemical symbol for each element. A chemical formula relays the chemical composition of a compound in a compact manner. These theoretical investigations provide valuable information for understanding why there occurs co-crystallization other than re-crystallization in DMF solution of HMX.Densities of some common chemicals and materials sample density (g/mL) cork 0.2 ethanol 0.8 water 1.0 rubber 1.1-1.2 salt 2.2 aluminum 2.7 cement 2.7-3.0 gold 19.3. MD simulation for the supersaturation solution of α-HMX in DMF presents the intermolecular interactions is in favor of co-crystallization. This means that the heteromeric intermolecular forces can compete with the homomeric intermolecular forces, and co-crystallization is possible to occur from the thermodynamics viewpoint.
![]() Workstation with Materials Studio (version 3.0), using the Compass force field.So far, no extrasolar planetary material with carbon-dominated geology has been detected (Wilson et al. Besides, it can improve the sensitive and mechanical properties of HMX. Besides, it can improve the sensitive and mechanical properties of HMX. Co-crystallization with other compounds may be an approach to avoid this problem. HMX as an ingredient in the vulnerability propellant formulation sometimes results in the reduction of the combustion velocity. Since its discovery, people have spent much time.HMX is easy to co-crystallize with DMF other than re-crystallization in DMF solution. Graphene is a 2D material that has many unique and excellent physical and electrical properties. There is an excess of oxygen relative to that which could be bound with the major rock-forming elements, including Mg, Si, Ni, Ca, and Fe.Abstract. So, the crystal structures of the HMX/DMF polymorphs have not been completely determined in experiments. Experiment has also not given the atom coordinates for the R 3 polymorph. In the R 3 c and C2/ c crystal structures, the DMF molecule exhibits twofold disorder and no positions have been retained. In the polymorphic forms of HMX/DMF, all HMX molecules present α-conformation possessing a crystallographic 2-fold axis. Hereinto, R 3 c is the most stable crystalline form. HMX/DMF crystallizes in three different polymorphic forms, belonging to R 3 c, C2/ c, and R 3 space groups , respectively. In general, for a crystalline system, if homomeric intermolecular forces dominate, re-crystallization occurs. Since the first reports of the crystal structures of HMX/DMF, fewer studies are devoted to mechanistic understanding of the co-crystallization process. So far, only several studies can be found. In terms of the most possible interaction manner, the homodimers and heterodimer of α-HMX and DMF are constructed based on their optimized structures. The initial geometries for single molecules are taken from the unit cells. 2 Methodology 2.1 Quantum chemistry calculationsAccording to X-ray powder diffraction experiments of β and α polymorphs of crystalline HMX (CSD code: OCHTET12 for β-HMX OCHTET for α-HMX) , we have built the unit cell models. The obtained results can provide important information for understanding the co-crystallization mechanism of HMX with DMF. So, in this work, we have investigated the structures and intermolecular interactions involved in the co-crystallization of HMX with DMF. Topcon 3d office priceThe DMF solvent has the reflective index n of 1.42817, dielectric constant ε of 36.7, and density ρ of 0.9445 g·cm -3 at 298 K. 2.2 Molecular dynamics simulationsThe conformation stability of HMX in DMF is explored by the MD simulation technique. Above all calculations are performed using the Gaussian03 package. Applying the PCM model, the relative stability of α and β HMX molecules in DMF is studied. A self-consistent reaction field (SCRF) method with the revised Polarized Continuum Model (PCM) is used to model the system in solution. Stabilization energy in vacuum is calculated using supermolecular approach and corrected by counterpoise (CP) method proposed by Boys and Bernardi. All the simulations are implemented on HPZ600 workstation with Materials Studio (version 3.0) , using the Compass force field. For potential energy calculations, the long-range Coulombic and vdW interactions are calculated by the standard Ewald method with a precision of 1×10 -6. The temperature control method is set to be Andersen, which chooses atom collision times from a Poisson distribution at each time step and changes their velocities according to the Boltzmann distribution.In MD simulations, the Verlet velocity time integration method is used and initial velocities are set through the Maxwell-Boltzmann profiles at given temperatures. MD simulation is carried out in the NVT ensemble with periodic boundary conditions. The energy minimization for the cubic box is carried out before the dynamics simulation. Logitech gaming software not detecting games1 we give the optimized geometries of HMX and DMF. The other conformation found in α and δ modifications of pure HMX and also believed to occur in γ-HMX is noted as the " α-HMX molecule". The ring conformation of HMX molecule in the β-form can be described as a chair conformation and will be referred to as the " β-HMX molecule" in this paper. The simulation temperature is set to be 335 K based on the experiments. Initially, DMF molecules are placed randomly around the HMX molecule. Therefore, the theoretical model for MD simulation is constructed by placing a β-HMX molecule in the cubic simulation box containing 200 DMF molecules (2428 atoms in total). These optimized monomers will be used to build the dimers in next section.Fig.1 Optimized geometries of HMX and DMF molecules at the MP2/6-31G * level (C atom in gray, and H atom in white)In experiment, crystals of HMX/DMF were prepared through cooling crystallization from the warm saturated solution of β-HMX in DMF. The calculated values for the dipole moment show that the α-HMX and DMF are strongly dipolar molecules, and their dipole moments are respectively 9.41 D and 4.28 D. A great degree of dipolar interaction between the nitro groups can be suggested for this disparity in the stability of the two conformations. ![]() The relative stability of α-HMX with respect to β-HMX is calculated to be 70.32 kJ·mol -1 in DMF. The calculated binding energy is 230.79 kJ/mol for β HMX and 301.11 kJ·mol -1 for α HMX. MM optimization is performed using the Smart Minimizer method with "fine" convergence level. Binding energy calculations are based on the cubic box containing 200 DMF molecules and a β-or α-HMX molecule optimized by molecular mechanics (MM) approach.
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