Computational Study of Structural, Electronic, and Optical Properties of Crystalline NH4N3
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- 作者：N. Yedukondalu ; Vikas D. Ghule ; G. Vaitheeswaran
- 刊名：The Journal of Physical Chemistry C
- 出版年：2012
- 出版时间：August 16, 2012
- 年：2012
- 卷：116
- 期：32
- 页码：16910-16917
- 全文大小：470K
- 年卷期：v.116,no.32(August 16, 2012)
- ISSN：1932-7455
文摘
A systematic computational study on the structural, electronic, bonding, and optical properties of orthorhombic ammonium azide (NH4N3) has been performed using planewave pseudopotential (PW-PP) method based on density functional theory (DFT). Semiempirical dispersion correction schemes have been used to account for nonbonded interactions in molecular crystalline NH4N3. The ground state lattice parameters, and fractional coordinates obtained using the dispersion correction schemes are in excellent agreement with experimental results. We calculated the single crystal elastic constants of NH4N3, and its sensitivity is interpreted through the observed ordering of the elastic constants (C33 > C11 > C22). The electronic structure and optical properties were calculated using full potential linearized augmented plane wave (FP-LAPW) approach with recently developed functional of Tran鈥揃laha modified Becke鈥揓ohnson (TB-mBJ) potential. The TB-mBJ electronic structure shows that NH4N3 is a direct band gap insulator with a band gap of 5.08 eV, while the calculated band gap with standard generalized gradient approximation is found to be 4.10 eV. The optical anisotropy is analyzed through the calculated optical constants, namely, dielectric function and refractive index along three different crystallographic axes. The absorption spectra reveal that NH4N3 is sensitive to ultraviolet (UV) light. Further, we also analyzed the detonation characteristics of the NH4N3 using the reported heat of formation and calculated density. NH4N3 is found to have a detonation velocity of 6.45 km/s and a detonation pressure about 15.16 GPa computed by Kamlet鈥揓acobs empirical equations.