Effect of lead and caesium on the mechanical, vibrational and thermodynamic properties of hexagonal fluorocarbonates: a comparative first principles study

Rao, E. Narsimha; Vaitheeswaran, G.; Reshak, A.H.; Auluck, S.

doi:10.1039/c6ra20408b

Cited by 15 publications

(14 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Born effective charge (BEC) is a result of the coupling between the electrostatic fields and lattice displacements. In order to explore more about the ionic and covalent bonding nature and to get in-depth knowledge about the polarization mechanism, we have calculated the BEC tensor and the infrared vibrational spectra of K 2 BDAF and K 2 DNABT using the DFPT method . The resultant BEC values of each individual atom of K 2 BDAF are tabulated in Table and results of K 2 DNABT are shown in Table S2 of the Supporting Information.…”

Section: Resultsmentioning

confidence: 99%

“…In order to explore more about the ionic and covalent bonding nature and to get in-depth knowledge about the polarization mechanism, we have calculated the BEC tensor and the infrared vibrational spectra of K 2 BDAF and K 2 DNABT using the DFPT method. 69 The resultant BEC values of each individual atom of K 2 BDAF are tabulated in Table 4 and results of K 2 DNABT are shown in Table S2 of the Supporting Information. In both cases, the sum of all BEC values are resulting in zero (acoustic sum rule Σ k Z k,ii * = 0), which indicates good convergence of our calculations within 0.0001 accuracy.…”

Section: ■ Calculation Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Structure–Property Correlation Studies of Potassium 4,4′-Bis(dinitromethyl)-3,3′-azofurazanate: A Noncentrosymmetric Primary Explosive

Rao

Vaitheeswaran

2019

J. Phys. Chem. C

Self Cite

View full text Add to dashboard Cite

The knowledge of mechanical, vibrational, electronic properties, and origin of polarizability of a noncentrosymmetric explosive materials plays a crucial role in understanding the phase transition mechanism and stand-off detection of high energy material (HEM) residues on the surfaces and interfaces. In the present study, we have explored the role of crystal structure and chemical composition in predicting the structural, dynamical, electronic, and optical properties of two newly synthesized noncentrosymmetric green primary explosives, potassium 4,4′-bis(dinitromethyl)-3,3′-azofurazanate (K 2 BDAF) and potassium 1,1′-dinitramino-5,5′-bistetrazolate (K 2 DNABT), using density functional theory simulations. The calculated structural and mechanical properties suggest that K 2 BDAF and K 2 DNABT are mechanically stable and possess lower bulk modulus values [K 2 BDAF (18.91 GPa) < K 2 DNABT (22.4 GPa)] than toxic lead azide Pb(N 3 ) 2 (26 GPa). The Born effective charge (BEC) and vibrational, thermodynamic, and phonon dispersion studies reveals that both crystals are dynamically stable and that K 2 BDAF is found to be more stable, more polarizable, and easily detectable than K 2 DNABT. The TB-mBJ electronic band structure study reveals that K 2 BDAF is an indirect band gap (along R → V high symmetry points) material with a gap of 2.37 eV < K 2 DNABT (3.57 eV, direct). The density of states and charge density plots show that both crystals possess mixed covalent and ionic bonding nature, and these results are consistent with BEC analysis. The nitrogen, oxygen and carbon p states are found to be dominant near the Fermi level in the valence band. From the optical properties study, it is found that the studied explosive materials have the lowest dielectric constant compared with the well-known 4-N,N-dimethylamino-4-N-methylstilbazolium tosylate (DAST) crystal, i.e., K 2 DNABT (2.68) < K 2 BDAF (2.91) < DAST (5.2), and show birefringence similar to (K 2 BDAF static value, 0.32; at 532 nm, 0.58), (K 2 DNABT static value, 0.25; at 532 nm, 0.27) that of DAST (0.39, 0.55, 0.64) and 4-N,Ndimethylamino-4′-N′-methylstilbazolium 2,4,6-trimethylbenzenesulfonate (DSTMS) (0.45, 0.63) NLO crystals. For both the studied explosives, the absorption is found to be strong in the [010] direction and follows the relation α(K 2 BDAF) < α(K 2 DNABT). The analysis of differences in BEC reveals that from K 2 DNABT to K 2 BDAF, the positive contribution of atoms to total birefringence increases as follows: K1 (0.09559), O1 (0.69236), O2 (0.77962), N1 (1.41018), N2 (0.92394), N3 (0.27415), N4 (0.74264), and N5 (0.84502). The negative contribution from C1 is increased by −1.29582. Over all, our results are in agreement with the experimentally reported sensitivity trend, and the reasons behind the sensitivity differences of K 2 DNABT and K 2 BDAF are explored.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: ■ Calculation Methodsmentioning

confidence: 99%

Structure–Property Correlation Studies of Potassium 4,4′-Bis(dinitromethyl)-3,3′-azofurazanate: A Noncentrosymmetric Primary Explosive

Rao

Vaitheeswaran

2019

J. Phys. Chem. C

Self Cite

View full text Add to dashboard Cite

show abstract

“…As the vibrational properties are very sensitive to the lattice vectors, it is important to optimize the crystal's structure to a better accuracy by including various interatomic interactions. 35,48 Hence, to capture the weak interlayer nonbonded interactions [van der Waals (vdW), hydrogen bond], we optimized all the crystal structures with the dispersion-corrected Grimme functional, that is, PBE + G06. 36 The obtained results show very good agreement with the experimental data, and the deviations of all of the obtained lattice vectors, volumes, and β values are around ∼1% (see Table 2).…”

Section: Acs Omegamentioning

confidence: 99%

Time-Domain Terahertz Spectroscopy and Density Functional Theory Studies of Nitro/Nitrogen-Rich Aryl-Tetrazole Derivatives

et al. 2020

View full text Add to dashboard Cite

The paper reports the time-domain THz spectroscopy studies of noncentrosymmetric energetic nitro/ nitrogen-rich aryl-tetrazole high-energy molecules. The fingerprint spectra in the THz domain reveal the role of different functional groups attached to position "1" of the tetrazole moiety, which controls the energetic properties. These responses are deliberated through density functional theory (DFT) calculations. The synthesized aryl-tetrazoles exhibit high positive heat of formation (369−744 kJ/mol), high detonation velocities, and pressures (D v : 7734−8298 m·s −1 ; D p : 24−28 GPa) in comparison to the noncentrosymmetric 2,4,6-trinitrotoluene (TNT). These compounds exhibit variation in the refractive indices and absorption between 0.1 and 2.2 THz range. The DFT studies at the molecular and single-crystal level (using plane wave pseudo potential method) endorse in detecting these bands (with ∼1% deviation). The calculated vibrational frequencies and linear optical properties are found to have good agreement with the experimental data in UV−visible and THz regions.

show abstract

“…Due to electrostatic adsorption, DNA can be adsorbed by positively charged ZIF-8. On the other hand, DNA bases contain aromatic rings that can bind to ZIF-8 through π–π stacking. − In light of this, in order to further understand the interaction between ZIF-8 and fluorescent probes, several influencing factors were explored in our investigation. Herein, we reported the ZIF-8 concentration, time, and effect of salt on adsorption.…”

Section: Introductionmentioning

confidence: 99%

Investigating Adsorption/Desorption of DNA on ZIF-8 Surface by Fluorescently Labeled Oligonucleotides

et al. 2019

View full text Add to dashboard Cite

As an important subclass of MOFs, ZIF-8, built from 2-methylimidazole and Zn(NO3)2·6H2O, possesses excellent biocompatibility and high stability in aqueous solution. Recently, it has been found that ZIF-8 can efficiently adsorb DNA and quench the adsorbed fluorophores to a large extent. These properties make it possible to prepare DNA-based optical sensors using ZIF-8. Although practical analytical applications are being demonstrated, the basic understanding of the binding between ZIF-8 and DNA in solution has received relatively little attention. In this work, we report that the adsorption of 12-, 18-, 24-, and 36-mer single-stranded DNAs on ZIF-8 are affected by several factors. It is found from the outcomes that shorter DNAs are adsorbed more rapidly to the surface of ZIF-8. On the other hand, desorption of the probe DNA can be achieved using complementary strand DNA to restore the fluorescence value. Furthermore, the salt contributes to adsorption to some extent. These findings are important for further understanding of the interactions between DNA and ZIF-8 and for the optimization of DNA and MOF-based devices and sensors.

show abstract

Effect of lead and caesium on the mechanical, vibrational and thermodynamic properties of hexagonal fluorocarbonates: a comparative first principles study

Abstract: The experimental crystal structure of CsPbCO3F consists of alternate CsF and PbCO3 layers.

Cited by 15 publications

References 54 publications

Structure–Property Correlation Studies of Potassium 4,4′-Bis(dinitromethyl)-3,3′-azofurazanate: A Noncentrosymmetric Primary Explosive

Structure–Property Correlation Studies of Potassium 4,4′-Bis(dinitromethyl)-3,3′-azofurazanate: A Noncentrosymmetric Primary Explosive

Time-Domain Terahertz Spectroscopy and Density Functional Theory Studies of Nitro/Nitrogen-Rich Aryl-Tetrazole Derivatives

Investigating Adsorption/Desorption of DNA on ZIF-8 Surface by Fluorescently Labeled Oligonucleotides

Contact Info

Product

Resources

About