| 1. |
- Adit Maark, T., et al.
(författare)
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Structural, electronic and thermodynamic properties of Al- and Si-doped α-, γ-, and β-MgH2 : Density functional and hybrid density functional calculations
- 2012
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 37:11, s. 9112-9122
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Tidskriftsartikel (refereegranskat)abstract
- In this work, we present a detailed study of Al- and Si-doped α-, γ-, and β-MgH 2 phases using the gradient corrected density functional GGA-PBE and the hybrid Hartree-Fock density functionals PBE0 and HSE06 within the framework of generalized Kohn-Sham density functional theory (DFT) using a plane-wave basis set. We investigate the structural, electronic, and thermodynamical properties of these compounds with regard to their hydrogen storage effectiveness. PBE0 and HSE06 predict cell parameters and bond lengths that are in good agreement with the GGA-PBE calculations and previously known experimental results. As expected smaller band gaps (E gs) are predicted by GGA-PBE for the pure magnesium hydride phases. PBE0 overcomes the deficiencies of DFT in treating these materials better than HSE06 and yields E gs that compare even better with previous GW calculations. Both the hybrid functionals increase the E gs of the Al-doped magnesium hydrides by much less magnitudes than of the Si-doped phases. This difference is interpreted in terms of charge density distributions. Best H 2 adsorption energies (ΔH ads) are computed by HSE06 while GGA-PBE significantly overestimates them. Si-doped α- and β-MgH 2 exhibited the least negative ΔH ads in close proximity to the H 2 binding energy range of -0.21 to -0.41 eV ideal for practical H 2 storage transportation applications.
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| 2. |
- Ahuja, Rajeev, et al.
(författare)
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Electronic and optical properties of gamma-Al2O3 from ab initio theory
- 2004
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Ingår i: Journal of Physics. - : IOP Publishing. - 0953-8984 .- 1361-648X. ; 16:16, s. 2891-2900
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Tidskriftsartikel (refereegranskat)abstract
- We report on a density functional theory calculation of the electronic structure and optical properties of gamma-Al2O3. We have made a comparison between the optical and electronic properties of the alpha and gamma phases of alumina. The calculated bulk modulus of the gamma phase is slightly lower than that of the a phase. The calculated static dielectric function and the optical constant of the gamma phase are very close to those of the alpha phase.
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| 3. |
- Ahuja, Rajeev, et al.
(författare)
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Electronic and optical properties of lead iodide
- 2002
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 92:12, s. 7219-7224
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Tidskriftsartikel (refereegranskat)abstract
- The electronic properties and the optical absorption of lead iodide (PbI2) have been investigated experimentally by means of optical absorption and spectroscopic ellipsometry, and theoretically by a full-potential linear muffin-tin-orbital method. PbI2 has been recognized as a very promising detector material with a large technological applicability. Its band-gap energy as a function of temperature has also been measured by optical absorption. The temperature dependence has been fitted by two different relations, and a discussion of these fittings is given.
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| 4. |
- Ahuja, Rajeev, et al.
(författare)
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High-pressure structural transitions in Cm and Am0.5Cm0.5 binary alloy
- 2006
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Ingår i: High Pressure Research. - : Informa UK Limited. - 0895-7959 .- 1477-2299. ; 26:4, s. 377-381
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Tidskriftsartikel (refereegranskat)abstract
- The high-pressure behaviour of Cm and Am0.5Cm0.5 binary alloy is investigated theoretically using ab initio electronic structure methods. Our calculations reproduce the structural phase transitions, which are observed in recent experiment performed by Heathman et al. [S. Heathman, R.G. Haire, I Le Bihan et al., Science 309 110 (2005)] and Lindbaum et al. [A. Lindbaum, S. Heathman, T. Le Bihan et al., J. Phys: Condens. Matter 15 S2297 (2003)]. Calculated transition pressures are in reasonable agreement with the experimental values. Calculations performed for an antiferromagnetic state are essential to reproduce the stability of Cm-III phase.
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| 5. |
- Ahuja, Rajeev, et al.
(författare)
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High pressure structural transitions in Cm metal
- 2006
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Ingår i: Mater Res Soc Symp Proc. - 1558998470 - 9781558998476 ; , s. 247-254
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Konferensbidrag (refereegranskat)abstract
- The high pressure behaviour of Cm metal is investigated theoretically using ab initio electronic structure methods. Our calculations reproduce the structural phase transitions which are obsereved in recent experiment performed by Heatman et al. [Science 309, 110 (2005)]. Calculated transition pressures are in reasonable agreement with the experimental values. Calculations performed for an antiferromagnetic state is essential to reproduce the stability of Cm-III phase. Thus, the stability of the Cm-III phase is related to the spin polarization of its 5f electrons.
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| 6. |
- Ahuja, Rajeev, et al.
(författare)
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Optical properties of 4H-SiC
- 2002
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 91:4, s. 2099-2103
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Tidskriftsartikel (refereegranskat)abstract
- The optical band gap energy and the dielectric functions of n-type 4H-SiC have been investigated experimentally by transmission spectroscopy and spectroscopic ellipsometry and theoretically by an ab initio full-potential linear muffin-tin-orbital method. We present the real and imaginary parts of the dielectric functions, resolved into the transverse and longitudinal photon moment a, and we show that the anisotropy is small in 4H-SiC. The measurements and the calculations fall closely together in a wide range of energies.
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| 7. |
- Ahuja, Rajeev, et al.
(författare)
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Optical properties of SiGe alloys
- 2003
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Ingår i: Journal of Applied Physics. - : AIP Publishing. - 0021-8979 .- 1089-7550. ; 93:7, s. 3832-3836
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Tidskriftsartikel (refereegranskat)abstract
- The optical properties of Si1-xGex have been investigated theoretically using a full-potential linear muffin-tin-orbital method. We present the density-of-states as well as the real and imaginary parts of the dielectric function. The calculated dielectric function was found to be in good agreement with the spectroscopic ellipsometry measurements by J. Bahng , J. Phys.: Condens. Matter 13, 777 (2001), and we obtained a static dielectric constant of epsilon(0)=12.19+2.45x in the Si rich regime (xless than or equal to0.5).
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| 8. |
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| 9. |
- Almeida, Roseley, et al.
(författare)
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Theoretical Evidence behind Bifunctional Catalytic Activity in Pristine and Functionalized Al2C Monolayers
- 2018
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Ingår i: ChemPhysChem. - : Wiley-VCH Verlagsgesellschaft. - 1439-4235 .- 1439-7641. ; 19:1, s. 148-152
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Tidskriftsartikel (refereegranskat)abstract
- First principles electronic structure calculations based on the density functional theory (DFT) framework are performed to investigate hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) on two-dimensional Al2C monolayers. In addition to the pristine Al2C monolayer, monolayers doped with Nitrogen (N), Phosphorous (P), Boron (B), and Sulphur (S) are also investigated. After determining the individual adsorption energy of hydrogen and oxygen on the different functionalized Al2C monolayers, the adsorption free energies are predicted for each of the functionalized monolayers in order to assess their suitability for HER or OER. The density of states and optical absorption spectra calculations along with the work function of the functionalized Al2C monolayers enable us to gain a profound understanding of the electronic structure for the individual system and their relation to the water splitting mechanism.
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| 10. |
- Alniss, Hasan Y., et al.
(författare)
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Investigation of the Factors That Dictate the Preferred Orientation of Lexitropsins in the Minor Groove of DNA
- 2019
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Ingår i: Journal of Medicinal Chemistry. - : AMER CHEMICAL SOC. - 0022-2623 .- 1520-4804. ; 62:22, s. 10423-10440
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Tidskriftsartikel (refereegranskat)abstract
- Lexitropsins are small molecules that bind to the minor groove of DNA as antiparallel dimers in a specific orientation. These molecules have shown therapeutic potential in the treatment of several diseases; however, the development of these molecules to target particular genes requires revealing the factors that dictate their preferred orientation in the minor grooves, which to date have not been investigated. In this study, a distinct structure (thzC) was carefully designed as an analog of a well-characterized lexitropsin (thzA) to reveal the factors that dictate the preferred binding orientation. Comparative evaluations of the biophysical and molecular modeling results of both compounds showed that the position of the dimethylaminopropyl group and the orientation of the amide links of the ligand with respect to the 5'-3'-ends; dictate the preferred orientation of lexitropsins in the minor grooves. These findings could be useful in the design of novel lexitropsins to selectively target specific genes.
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