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Context: The key factor in designing heat-resistant energetic materials is their thermal sensitivity. Further research and prediction of thermal sensitivity remains a great challenge for us. This study is based on first-principles calculations and establishes a theoretical model, which comprehensively considers band gap, density of states, and Young's modulus to obtain a empirical parameter Ψ. A quantitative relationship was established between the new parameter and the thermal decomposition temperature. The value of Ψ is calculated for 10 energetic materials and is found to have a strong correlation with the experimental thermal decomposition temperature. This further proves the reliability of our model. Specifically, the larger the value of Ψ, the higher the thermal decomposition temperature, and the more stable the energetic material will be. Therefore, to some extent, we can use the new parameter Ψ calculated by the model to predict thermal sensitivity. Methods: Based on first-principles, this paper used the Cambridge Serial Total Energy Package (CASTEP) module of Materials Studio (MS) for calculations. The Perdew-Burke-Ernzerhof (PBE) functionals in Generalized Gradient Approximation (GGA) method as well as the Grimme dispersion correction was used in this paper. [ABSTRACT FROM AUTHOR]

Context: To find the potential value of Ca3N2 in the field of optoelectronics, the physical properties of Ca3N2 will be analyzed. It can be concluded from the electronic properties that the Ca-N bonds of α-Ca3N2 are more stable than those of δ-Ca3N2 and ε-Ca3N2. The dielectric function, reflectivity function, and absorption function of three types of Ca3N2 were accurately calculated, and it was concluded that α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 have greater transmittance for visible light and exhibit optical transparency in the near-infrared frequency domain. Combined with the high hardness, strong bonding, high melting point, and wear resistance of Ca3N2, Ca3N2 can be used as a new generation of window heat-resistant materials. The α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 are indirect, direct, and indirect narrow bandgap compounds, respectively, that is, δ-Ca3N2 is more suitable for luminescent materials than α-Ca3N2 and ε-Ca3N2. α-Ca3N2 and δ-Ca3N2 have high reflective properties in the ultraviolet region and can be used as UV protective coatings. All three Ca3N2 materials can be used industrially to synthesize photovoltaic devices that operate in the ultraviolet region. Methods: Based on the first-principles of density functional theory calculations, the structures, electronic properties, and optical properties of α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 were calculated. The calculation results show that although the α-Ca3N2, δ-Ca3N2, and ε-Ca3N2 have similar electronic structures, some phases have better properties in some aspects. [ABSTRACT FROM AUTHOR]

This study reports a theoretical examination of the structural, electronic, and mechanical properties of the tetragonal structure of Y7Ru4InGe12 by using the generalized gradient approximation of the density functional theory and the plane wave ab initio pseudopotential method. We have mainly studied the electronic properties of the compound. The calculated results of the band structure show that the addition of rare earth elements has a greater effect on Fermi levels. By studying density of states, it is found that Y, Ge, and Ru atoms contribute most to Fermi levels. At the same time, we also studied the partial density of states of Y and Ge atoms in different positions. By calculating the value of B (bulk modulus)/G (shear modulus), Poisson's ratio and Cauchy's pressure found that the compound exhibited ductility. Poisson's ratio can also be used to define the bonding properties of compounds. The results of the calculations show that the superconductivity of Y7Ru4InGe12 is due to significant metallic bonding. The calculated elastic constants show that the compound is mechanically stable. [ABSTRACT FROM AUTHOR]

The structural, electronic, optical, and vibrational properties of B3N3H6 have been calculated by means of the first-principles density functional theory (DFT) calculations within the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structural parameters of B3N3H6 are in good agreement with experimental data. The obtained band structure of B3N3H6 shows that it has an indirect band gap with 5.007 eV, indicating that it presents insulation characteristic. The total and partial density of states (DOS) of B3N3H6 are given, which tell us the states of the orbital occupation. With the band structure and density of states, we have analyzed the optical properties including the complex dielectric function, refractive index, absorption, conductivity, loss function, and reflectivity. By the contrast, it is found that optical anisotropy is observed in the (001) direction and (100) direction. Moreover, the vibrational properties have been obtained and analyzed, showing that B3N3H6 is dynamically stable due to that there is no imaginary frequency. The frequencies associating with the vibrations are given, which show that B3N3H6 has a low mechanical modulus and thermal conductivity. [ABSTRACT FROM AUTHOR]

The structure, electronic, and magnetic properties have been investigated by the first-principles calculations for paramagnetic, ferromagnetic, and antiferromagnetic Cu3TeO6 under pressure from 0 to 100 GPa. The calculated lattice parameters at 0 GPa are in excellent agreement with the available calculated and experimental values. With increasing pressure, the lattice parameters and volume decrease, but Cu3TeO6 keeps a stable cubic structure. The electronic calculations show that paramagnetic and ferromagnetic Cu3TeO6 are metallic, and antiferromagnetic Cu3TeO6 is non-metallic with a direct band gap which decreases with the increasing pressure. Under the pressure, their non-locality of density of states enhances and the electrons become more active. Moreover, for antiferromagnetic Cu3TeO6, the spin moments of Cu atoms are affected obviously by pressures, and Te atoms show nonmagnetic performance. The total magnetic moment, which is mainly contributed by Cu, reaches the maximum at 20 GPa, and decreases with the increasing pressure. The knowledge of these properties will provide reference and guidance for the subsequent study of Cu3TeO6. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) has been employed within the generalized gradient approximation and Perdew–Burke–Ernzerhof functional (GGA-PBE) to study the structural and electronic properties of nitromethane (NM) surface models. Different surfaces, including (100), (001), (101), (110), and (111), are considered in this work. The corresponding properties of bulk crystal for NM were also calculated to form a contrast to the slab models. Results with anisotropic characteristics of different surfaces have been observed in this study. There was an obviously great anisotropy in electronic parameters, especially the band gaps of different surfaces, indicating the anisotropic impact sensitivity along different directions of NM. The band gap value for (111) surface, 2.687 eV, was smaller than that of other surfaces, showing a higher impact sensitivity for NM. The estimated anisotropy has been revealed in surface energies for different surfaces. [ABSTRACT FROM AUTHOR]

The structure, electronic, and magnetic properties have been investigated by the first-principles calculations for paramagnetic, ferromagnetic, and antiferromagnetic Cu3TeO6 under pressure from 0 to 100 GPa. The calculated lattice parameters at 0 GPa are in excellent agreement with the available calculated and experimental values. With increasing pressure, the lattice parameters and volume decrease, but Cu3TeO6 keeps a stable cubic structure. The electronic calculations show that paramagnetic and ferromagnetic Cu3TeO6 are metallic, and antiferromagnetic Cu3TeO6 is non-metallic with a direct band gap which decreases with the increasing pressure. Under the pressure, their non-locality of density of states enhances and the electrons become more active. Moreover, for antiferromagnetic Cu3TeO6, the spin moments of Cu atoms are affected obviously by pressures, and Te atoms show nonmagnetic performance. The total magnetic moment, which is mainly contributed by Cu, reaches the maximum at 20 GPa, and decreases with the increasing pressure. The knowledge of these properties will provide reference and guidance for the subsequent study of Cu3TeO6. [ABSTRACT FROM AUTHOR]

Context and Results: The structure, mechanical, electronic, vibration, and hydrogen bonding properties of a novel high-energy and low-sensitivity 5, 5'-dinitroamino-3, 3'-azo-oxadiazole 4, 7-diaminopyridazino [4, 5-c] furoxan salt have been studied by density functional theory. The calculated vibrational properties show that the low-frequency mode is mainly contributed by the vibration of the -NO2 group, and the high-frequency mode is mainly contributed by the vibration of the -NH2 group and the N7-H3 bond which protonates the cation. In addition, it is analyzed that the first bond to break may be the N-NO2 bond. The calculated hydrogen bond properties indicate that the hydrogen bond between water molecules and cations is N7-H3… O5 (1.563 Å), which is the shortest hydrogen bond among all hydrogen bonds. The presence of this exceptionally short hydrogen bond renders the N7-H3 and H6-O5 bonds resistant to disruption at high frequencies, underscoring the pivotal role of hydrogen bonding in stabilizing the structure of energetic materials. Given the absence of experimental and theoretical data on the electronic, mechanical, and vibrational properties of the material thus far, our calculations offer valuable theoretical insights into the ionic salts of high energy and low sensitivity., Computational Methods: All calculations have been carried out based on density functional theory (DFT) and implemented in the CASTEP code. The mode-conserving pseudopotential is utilized to describe the plane wave expansion function, while the PBE functional within the generalized gradient approximation (GGA) is employed to characterize the exchange-correlation interaction. Additionally, dispersion correction is applied using Grimme's DFT-D method., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Context: Energy-containing materials such as explosives have attracted considerable interest recently. In the field of high-energy materials, tetrazine and its derivatives can largely meet the requirements of high nitrogen content and oxygen balance. Nitrogen-rich energetic salts are important research subjects. Nitrogen-rich salt of 3,6-dinitramino-1,2,4,5-tetrazine is a high-energy nitrogen-rich material, but there are few related studies. This paper systematically studies the crystal structure and electronic, vibrational, and thermodynamic properties of (NH 4 ) 2 (DNAT). The lattice parameters of (NH 4 ) 2 (DNAT) are observed to align well with the experimental values. The properties of electrons are analyzed by band structure and density of states (DOS). The phonon dispersion curves indicate that the compound is dynamically stable. The vibrational modes of bonds and chemical groups are described in detail, and the peaks in the Raman and infrared spectra are assigned to different vibration modes. Based on the vibration characteristics, thermodynamic properties such as enthalpy (H), Helmholtz free energy (F), entropy (S), Gibbs free energy (G), constant volume heat capacity (C V ), and Debye temperature (Θ) are analyzed. This article can pave the way for subsequent work or provide data support to other researchers, promoting further research., Methods: In this study, we utilized the density functional theory (DFT) for our calculations. The exchange-correlation potential and van der Waals interactions were characterized based on the GGA-PBE + G function calculation. We obtained Brillouin zone integrals using Monkhorst-Pack k-point grids, with the k-point of the Brillouin zone set to a 2 × 2 × 2 grid. During the self-consistent field operation, we set the total energy convergence tolerance to 5 × 10 -6  eV per atom. The cut-off energy for the calculation was established at 830 eV. Additionally, the states of H (1s 1 ), C (2s 2 2p 2 ), N (2s 2 2p 3 ), and O (2s 2 2p 4 ) were treated as valence electrons in our study., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Context: To find the potential value of Ca 3 N 2 in the field of optoelectronics, the physical properties of Ca 3 N 2 will be analyzed. It can be concluded from the electronic properties that the Ca-N bonds of α-Ca 3 N 2 are more stable than those of δ-Ca 3 N 2 and ε-Ca 3 N 2 . The dielectric function, reflectivity function, and absorption function of three types of Ca 3 N 2 were accurately calculated, and it was concluded that α-Ca 3 N 2 , δ-Ca3N 2 , and ε-Ca 3 N 2 have greater transmittance for visible light and exhibit optical transparency in the near-infrared frequency domain. Combined with the high hardness, strong bonding, high melting point, and wear resistance of Ca 3 N 2 , Ca3N 2 can be used as a new generation of window heat-resistant materials. The α-Ca 3 N 2 , δ-Ca 3 N 2 , and ε-Ca 3 N 2 are indirect, direct, and indirect narrow bandgap compounds, respectively, that is, δ-Ca 3 N 2 is more suitable for luminescent materials than α-Ca 3 N 2 and ε-Ca 3 N 2 . α-Ca 3 N 2 and δ-Ca 3 N 2 have high reflective properties in the ultraviolet region and can be used as UV protective coatings. All three Ca 3 N 2 materials can be used industrially to synthesize photovoltaic devices that operate in the ultraviolet region., Methods: Based on the first-principles of density functional theory calculations, the structures, electronic properties, and optical properties of α- Ca3N2 , δ-Ca 3 N 2 , and ε-Ca 3 N 2 were calculated. The calculation results show that although the α-Ca 3 N 2 , δ-Ca 3 N 2 , and ε-Ca 3 N 2 have similar electronic structures, some phases have better properties in some aspects., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

This study reports a theoretical examination of the structural, electronic, and mechanical properties of the tetragonal structure of Y 7 Ru 4 InGe 12 by using the generalized gradient approximation of the density functional theory and the plane wave ab initio pseudopotential method. We have mainly studied the electronic properties of the compound. The calculated results of the band structure show that the addition of rare earth elements has a greater effect on Fermi levels. By studying density of states, it is found that Y, Ge, and Ru atoms contribute most to Fermi levels. At the same time, we also studied the partial density of states of Y and Ge atoms in different positions. By calculating the value of B (bulk modulus)/G (shear modulus), Poisson's ratio and Cauchy's pressure found that the compound exhibited ductility. Poisson's ratio can also be used to define the bonding properties of compounds. The results of the calculations show that the superconductivity of Y 7 Ru 4 InGe 12 is due to significant metallic bonding. The calculated elastic constants show that the compound is mechanically stable., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The structural, electronic, optical, and vibrational properties of B 3 N 3 H 6 have been calculated by means of the first-principles density functional theory (DFT) calculations within the generalized gradient approximation (GGA) and the local density approximation (LDA). The calculated structural parameters of B 3 N 3 H 6 are in good agreement with experimental data. The obtained band structure of B 3 N 3 H 6 shows that it has an indirect band gap with 5.007 eV, indicating that it presents insulation characteristic. The total and partial density of states (DOS) of B 3 N 3 H 6 are given, which tell us the states of the orbital occupation. With the band structure and density of states, we have analyzed the optical properties including the complex dielectric function, refractive index, absorption, conductivity, loss function, and reflectivity. By the contrast, it is found that optical anisotropy is observed in the (001) direction and (100) direction. Moreover, the vibrational properties have been obtained and analyzed, showing that B 3 N 3 H 6 is dynamically stable due to that there is no imaginary frequency. The frequencies associating with the vibrations are given, which show that B 3 N 3 H 6 has a low mechanical modulus and thermal conductivity., (© 2021. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The detailed illustrations of the structures, elastic properties, and Raman and IR vibration modes for [Na(H 2 O)(N 5 )]·2H 2 O (a) and [Mg(H 2 O) 6 (N 5 ) 2 ]·4H 2 O (b) have been presented in this investigation by using the first-principles method based on the density functional theory. Our results indicate that the active centers of both two types of the energetic metal pentazolate hydrates appear on the cyclo-N 5 . The bonding character of N atoms in the cyclo-N 5 is shown to be covalent, and the cyclo-N 5 ring can be considered as an anion. Based on the analysis of elastic properties, we conclude that complex a is easier to deform than b, and both complexes are mechanically stable. From the calculated Raman and IR vibration modes, the vibration in the region of 960-1206 cm -1 (for a) and 985-1208 cm -1 (for b) is determined by basically mixing the cyclo-N 5 stretching and deformation modes. The vibrational modes of a and b in their highest frequency zones are both related to the stretching of the O-H bonds.

Density functional theory (DFT) has been employed within the generalized gradient approximation and Perdew-Burke-Ernzerhof functional (GGA-PBE) to study the structural and electronic properties of nitromethane (NM) surface models. Different surfaces, including (100), (001), (101), (110), and (111), are considered in this work. The corresponding properties of bulk crystal for NM were also calculated to form a contrast to the slab models. Results with anisotropic characteristics of different surfaces have been observed in this study. There was an obviously great anisotropy in electronic parameters, especially the band gaps of different surfaces, indicating the anisotropic impact sensitivity along different directions of NM. The band gap value for (111) surface, 2.687 eV, was smaller than that of other surfaces, showing a higher impact sensitivity for NM. The estimated anisotropy has been revealed in surface energies for different surfaces. Graphical Abstract The valence band minimum (VBM) and conduction band maximum (CBM) of the nitromethane (100), (001), (101), (110) and (111) surface models.