Accurate Predictions of Crystal Densities Using Quantum Mechanical Molecular Volumes

Abstract

A quantum mechanically based procedure for estimation of crystal densities of neutral and ionic crystals is presented. In this method, volumes within 0.001 electrons/bohr3 isosurfaces of electron density for the constituent isolated neutral and ionic molecules are calculated to define the molecular volume or formula unit volumes used in predicting the crystal density. The B3LYP density functional theory in conjunction with the 6-31G** basis set were employed to generate the electron densities. The suitability of this method of crystal density prediction was assessed by subjecting a large number (289) of molecular and ionic crystals to the procedure and comparing results with experimental information. The results indicate that, for neutral molecular crystals, the root-mean-square (rms) deviation from experiment is within 4%, whereas the rms deviation is somewhat larger for the 71 ionic crystals evaluated (within 5%).

Computational Investigation on the Structure and Performance of Novel 4,7-Dinitro-furazano-[3,4-d]-pyridazine Derivatives

“…The volumes of the title compounds were defined as inside a contour of 0.001 electrons/bohr 3 density, estimated using a Monte Carlo integration [17,27,28], then the average volumes were estimated by performing 100 single-point energy calculation for each optimized structure.…”

“…The BDE is regarded as a quite convincing index for molecular stability [27,34], and means the difference between the energy of a molecule and those of the radicals produced when a bond in the molecule is broken. It is important to understand the pyrolysis mechanism of the compound [35][36][37].…”

Prediction of the Density of Energetic Materials on the Basis of their Molecular Structures

“…For estimating the crystal density of available energetic materials, various methods have been developed. These include electrostatic potentials using quantum-mechanically determined molecular volumes [11][12][13][14][15], group additivities [8,9,[16][17][18], empirical methods [19][20][21][22] and Quantitative Structure-Property Relationships (QSPR) [23].…”

A Study of the Detonation Properties, Propellant Impulses, Impact Sensitivities and Synthesis of Nitrated ANTA and NTO Derivatives

“…These two parameters can be calculated by quantum chemical methods [12][13][14][15]. Furthermore, a number of additional parameters such as bond dissociation energies, Mulliken charges and electrostatic potentials, that can provide an indication of the impact sensitivity, can also be computed [16][17][18][19][20].…”