Vibrational and thermodynamic properties of β-HMX: A first-principles investigation

Abstract

Prediction of the phase behavior of acetonitrile and methanol with ab initio pair potentials. II. The mixture We present pair potentials for fluorinated methanes and their dimers with CO 2 based on ab initio potential energy surfaces. These potentials reproduce the experimental second virial coefficients of the pure fluorinated methanes and their mixtures with CO 2 without adjustment. Ab initio calculations on trimers are used to model the effects of nonadditive dispersion and induction. Simulations using these potentials reproduce the experimental phase-coexistence properties of CH 3 F within 10% over a wide range of temperatures. The phase coexistence curve of the mixture of CH 2 F 2 and CO 2 is reproduced with an error in the mole fractions of both phases of less than 0.1. The potentials described here are based entirely on ab initio calculations, with no empirical fits to improve the agreement with experiment.

Ab initio Investigation of Interfacial Thermal Transport for HMX‐PVDF Interface

“…As Table 1 shows, our calculated Raman frequency results are comparable to the data by theoretical calculation [34] and Raman scattering measurement [35,36]. In low-frequency region, our results are consistent with Wu's result [34] and show slightly lower than that of experiment. In the middle-frequency region, results are close to the experimental data and better than other theoretical results.…”

“…In the middle-frequency region, results are close to the experimental data and better than other theoretical results. In high frequency, the calculated results are slightly higher than that of experiment and LDA calculation [34]. Generally, calculated Raman results show good consistency that proves our calculation results are convincing and available to use in the following calculation.…”

“…Due to the lack of experimental phonon dispersion data to compare, we choose the Raman vibrational frequency at Γ point to compare the existed theoretical [34] and experimental [35,36] work for HMX. The irreducible representations Ag, Bg which have inversion symmetry are Raman active.…”

“…Here, we use the experimental results of a, B and V to calculate C P . Figure 2(a) demonstrates the calculate heat capacity of HMX as a function of temperature in comparison with experimental [38] and calculation [34,39,40] results. Solid and dash red lines represent C P and C V respectively.…”

Vibrational and Thermodynamic Properties of 1,3,5-Triamino-2,4,6-Trinitrobenzene (Tatb): Comparison of Exchange-Correlation Functionals in Density Functional Theory

“…Furthermore, these potentials have been shown to predict TATB properties at high pressures and temperatures reasonably well (Bedrov et al, 2009;Gee et al, 2004;Rai et al, 2008). In contrast, nonempirical electronic-structure calculations usually have considerable errors in crystal properties of TATB Liu et al, 2007;Wu et al, 2003) and other molecular crystals Byrd et al, 2004;Conroy et al, 2008aConroy et al, , 2008bQiu et al, 2006;Shimojo et al, 2010;Wu et al, 2011;Zhao and Liu, 2008). For example, the generalized gradient approximation (GGA), which is a commonly used exchange-correlation (xc) functional in DFT calculations, tends to overestimate the equilibrium volume of TATB by 20∼30% Liu et al, 2007), while another popular xc functional, the local density approximation (LDA), underestimates it by 10∼15% Liu et al, 2007;Wu et al, 2003).…”