Structural, mechanical, electronic, vibrational and thermodynamic properties of Bis(2,4-dinitrophenyl) ether

Abstract

Bis (2,4-dinitrophenyl) ether (BDNPE) is a nitroaromatic compound with potential applications as a low sensitivity energetic material, but there is a lack of comprehensive understanding of its structure property relationship. In this study, we systematically investigated the mechanical, electronic, vibrational, and thermodynamic properties of BDNPE using density functional theory (DFT) combined with quasi harmonic approximation (QHA). The deviation between the optimized lattice parameters and the experimental crystallographic data is less than 3 %. The optimized crystal structure exhibits anisotropic mechanical behavior, with a bulk modulus of B = 11.09 GPa and a shear modulus of G = 4.74 GPa, indicating moderate rigidity. Pugh ratio (G/B = 0.427) and Poisson's ratio (ν = 0.313) confirm ductile behavior. Electronic structure analysis shows that the direct bandgap is 2.17 eV, mainly due to strong hybridization between O-2p and N-2p orbitals. The phonon dispersion calculation confirms the dynamic stability and proves the reliability of our method. Vibration spectroscopy analysis (IR and Raman) showed characteristic peaks corresponding to specific functional group vibrations. The medium-high frequency mode (1200-3200 cm⁻¹) is mainly attributed to the aromatic C–H oscillation. The low-frequency region (600-900 cm⁻¹) contains ring deformation modes, out of plane C–H, and nitro oscillation vibrations. The temperature dependent thermodynamic functions were derived through quasi harmonic approximation, including Helmholtz free energy (F), entropy (S), enthalpy (H), Gibbs free energy (G), and isochoric heat capacity (Cv). These computational results establish important benchmarks for future experimental validation and provide critical insights for the design of BDNPE based materials.