Quasi-1D physics in metal-organic frameworks: MIL-47(V) from first principles

• Danny E. P. Vanpoucke,
• Jan W. Jaeken,
• Stijn De Baerdemacker,
• Kurt Lejaeghere and
• Veronique Van Speybroeck

Beilstein J. Nanotechnol. 2014, 5, 1738–1748, doi:10.3762/bjnano.5.184

• framework (MOF) is investigated by using ab initio density functional theory (DFT) calculations. Special focus is placed on the relation between the spin configuration and the properties of the MOF. The ground state is found to be antiferromagnetic, with an equilibrium volume of 1554.70 Å3. The transition

• ][19][20][21][22][50][51]. The size of the MIL-47 system, however, limits the computational possibilities. As a result, most theoretical work in the above studies is limited to force-field based simulations [7][10][12][13][18][19][20][22][51]. In these, DFT calculations are often used to provide

• partial charges. Due to their computational cost (the work presented in this paper amounts to 25 years of CPU time), DFT calculations for other purposes tend to be limited to fixed geometries [50] or small k-point sets [53], with some exceptions [22]. In this paper, the influence of the spin configuration

Nano-rings with a handle – Synthesis of substituted cycloparaphenylenes

• Anne-Florence Tran-Van and
• Hermann A. Wegner

Beilstein J. Nanotechnol. 2014, 5, 1320–1333, doi:10.3762/bjnano.5.145

• ring strain and led to a complex mixture of partially dehydrogenated and chlorinated products. A clear evidence for the formation of [3]CHBC was not obtained. DFT calculations showed that the molecule is C3-symmetric with a twisted CPP core and a diameter of 12.2 Å in the gas phase. In the calculated

• and coworkers also reported the synthesis of a [4]cyclo-2,7-pyrenylene ([4]CPY) by using their method with a square-like tetra-Pt-complex [53]. DFT-calculations as well as electrochemical analysis revealed a strong resemblance with [8]CPP. During the evolution of larger π-extended nanobelts, Itami

• studied by DFT calculations. Here again the most stable conformation is the cis form. The results show that the transition takes place through rotation of one of the CPP rings around the connected benzene ring with a barrier of 8.9 kcal/mol indicating a fast isomerisation process at room temperature

Sublattice asymmetry of impurity doping in graphene: A review

• James A. Lawlor and
• Mauro S. Ferreira

Beilstein J. Nanotechnol. 2014, 5, 1210–1217, doi:10.3762/bjnano.5.133

• leads to a same sublattice configuration for all impurities in a domain. Through density functional theory (DFT) calculations involving a graphene nanoribbon on a Cu(111) substrate, aiming to reproduce experimental conditions, a thorough investigation into the energetic favourable position of single

• , comes from matching tight binding and DFT band structure results, a method which is known to systematically underestimate such band gaps. Nevertheless, the band gap obtained can be expected to be much below that required for a GFET device. In-depth DFT calculations by Hou et al. [44] found that the

DFT study of binding and electron transfer from colorless aromatic pollutants to a TiO₂ nanocluster: Application to photocatalytic degradation under visible light irradiation

• Corneliu I. Oprea,
• Petre Panait and
• Mihai A. Gîrţu

Beilstein J. Nanotechnol. 2014, 5, 1016–1030, doi:10.3762/bjnano.5.115

• Corneliu I. Oprea Petre Panait Mihai A. Girtu Department of Physics, Ovidius University of Constanţa, Constanţa 900527, Romania 10.3762/bjnano.5.115 Abstract We report results of density functional theory (DFT) calculations on some colorless aromatic systems adsorbed on a TiO2 nanocluster, in

• ]. Theoretically, density functional theory (DFT) calculations showed [21][22][23] that the binding of the carboxy group to titania is bidentate bridging, with the monodentate anchoring being less stable [24][25][26][27]. The higher performance of the dyes with both carboxy and hydroxy anchoring groups [28] has

• ]. Building upon the experience gained while modeling materials for photoelectrochemical cells, we report here results of DFT and time dependent DFT (TD-DFT) calculations performed on several colorless aromatic pollutants, as well as complex systems consisting of benzene derivatives adsorbed on a TiO2

Double layer effects in a model of proton discharge on charged electrodes

• Johannes Wiebe and
• Eckhard Spohr

Beilstein J. Nanotechnol. 2014, 5, 973–982, doi:10.3762/bjnano.5.111

• particular, at the negative surface charge densities studied here, one can expect the existence of a hydrogen UPD layer and fast discharge, which is indeed consistent with the results of the model. Recent DFT calculations by the Groß group [34] showed that the existence of such a layer moves the water layer

• has an ordering effect on the surrounding water molecules (analogous to the one observed by the Gross group for water around an OH group on a Ru surface by using DFT calculations [39]), which is evident from the correlation of the proton discharge sites with the ions and with the on top water site in

Growth and characterization of CNT–TiO₂ heterostructures

• Yucheng Zhang,
• Ivo Utke,
• Johann Michler,
• Gabriele Ilari,
• Marta D. Rossell and
• Rolf Erni

Beilstein J. Nanotechnol. 2014, 5, 946–955, doi:10.3762/bjnano.5.108

• multiple scattering are developed, either in the reciprocal space or in the real space, to simulate the ELNES of both crystalline and amorphous materials [50]. Titantah et al. performed DFT calculations of ELNES on CNTs, taking into consideration the effect of curvatures, the electron-beam orientation as

Classical molecular dynamics investigations of biphenyl-based carbon nanomembranes

• Andreas Mrugalla and
• Jürgen Schnack

Beilstein J. Nanotechnol. 2014, 5, 865–871, doi:10.3762/bjnano.5.98

• stripe configuration always forms (for all reasonable γ). This is in part also observed in DFT calculations [8]. Only for a sufficient randomization of the initial state, which corresponds to a substantial excitation and to the breakup of sufficiently many phenyls, a true cross-linking is observed. The

Resonance of graphene nanoribbons doped with nitrogen and boron: a molecular dynamics study

• Ye Wei,
• Haifei Zhan,
• Kang Xia,
• Wendong Zhang,
• Shengbo Sang and
• Yuantong Gu

Beilstein J. Nanotechnol. 2014, 5, 717–725, doi:10.3762/bjnano.5.84

• electrical properties of Pt, Fe, and Al NPs adsorbed on monovacancy-defective graphene were explored by density functional theory (DFT) calculations [17][18]. To accommodate different applications of graphene derivatives, a comprehensive understanding of their mechanical properties is crucial. For instance

Constant chemical potential approach for quantum chemical calculations in electrocatalysis

• Wolfgang B. Schneider and
• Alexander A. Auer

Beilstein J. Nanotechnol. 2014, 5, 668–676, doi:10.3762/bjnano.5.79

• potential [25]. This scheme is the quantum chemical equivalent to an approach by Alavi et al. [26], that focused on constant electrochemical potential schemes in the framework of periodic boundary condition DFT calculations. Based on the possibility to calculate the electronic structure of a finite system

• electrochemical potential in the framework of a Grand Canonical Ensemble DFT ansatz is presented. In contrast to common DFT calculations, that are carried out at a constant number of electrons N, the energy is calculated for a fixed electrochemical potential with a variable fractional number of electrons. While

Effects of the preparation method on the structure and the visible-light photocatalytic activity of Ag₂CrO₄

• Difa Xu,
• Shaowen Cao,
• Jinfeng Zhang,
• Bei Cheng and
• Jiaguo Yu

Beilstein J. Nanotechnol. 2014, 5, 658–666, doi:10.3762/bjnano.5.77

• scattering with a zetasizer (Nano ZS90, Malvern, UK). Computational details The DFT calculations were carried out to investigate the band structure and density of states (DOS) of Ag2CrO4 model by using the CASTEP Packages on the basis of the plane-wave-pseudo-potential approach [77][78]. Combined with

Neutral and charged boron-doped fullerenes for CO₂ adsorption

• Suchitra W. de Silva,
• Aijun Du,
• Wijitha Senadeera and
• Yuantong Gu

Beilstein J. Nanotechnol. 2014, 5, 413–418, doi:10.3762/bjnano.5.49

• . Computational Details First-principles density functional theory (DFT) calculations were carried out to study CO2 adsorption on the BC59 cage. The BC59 structure was fully optimized in the given symmetry. The calculations were carried out at B3LYP [20][21][22] level of theory while using the split valance

• than 350 K. Therefore we suggest a method of manipulating the charge state and the temperature of the system for adsorbent recycling. Charging the system can be achieved by electrochemical methods, electrospray, and electron beam or gate voltage control methods [8]. Conclusion By using DFT calculations

The role of surface corrugation and tip oscillation in single-molecule manipulation with a non-contact atomic force microscope

• Christian Wagner,
• Norman Fournier,
• F. Stefan Tautz and
• Ruslan Temirov

Beilstein J. Nanotechnol. 2014, 5, 202–209, doi:10.3762/bjnano.5.22

• simulate the intramolecular mechanics of PTCDA, fitting it explicitly to DFT calculations of the mechanical properties of a gas phase molecule. The intramolecular force-field parameters are kept fixed through the rest of the simulation. The molecule–tip bond is described by a spherical Morse potential (D

Change of the work function of platinum electrodes induced by halide adsorption

• Florian Gossenberger,
• Tanglaw Roman,
• Katrin Forster-Tonigold and
• Axel Groß

Beilstein J. Nanotechnol. 2014, 5, 152–161, doi:10.3762/bjnano.5.15

• adsorption of iodine and chlorine on Cu(111) [9] by using periodic density functional theory (DFT) calculations. Whereas chlorine causes the expected increase of the work function upon adsorption of an electronegative adsorbate, iodine leads to a surprising decrease of the work function for coverages up to

Core level binding energies of functionalized and defective graphene

• Toma Susi,
• Markus Kaukonen,
• Paula Havu,
• Mathias P. Ljungberg,
• Paola Ayala and
• Esko I. Kauppinen

Beilstein J. Nanotechnol. 2014, 5, 121–132, doi:10.3762/bjnano.5.12

• can be compared is needed. Density functional theory (DFT) calculations can be employed to provide such a reference, especially when measurements of known molecular systems are not sufficient. However, because of the computational cost of treating core levels accurately, most calculations up to date

• photelectron: Eb = hν − Ek, which leads to Eb = Ef − Ei, the difference between final and initial energies of the target system. For the DFT calculations, we used the real-space grid-based projector-augmented wave (GPAW) code [12]. Recently, core-hole calculations that utilize a delta Kohn–Sham (∆K–S) total

The role of oxygen and water on molybdenum nanoclusters for electro catalytic ammonia production

• Jakob G. Howalt and
• Tejs Vegge

Beilstein J. Nanotechnol. 2014, 5, 111–120, doi:10.3762/bjnano.5.11

• . In addition, the blocking of active sites by oxygen species has been explored; together with a determination of reduction pathways to electrochemically reduce the blocking oxygen off the surface. Computational Method DFT calculations The calculations were carried out with density functional theory

• (DFT) calculations [7][8] using the RPBE exchange correlation functional [9] along with the projector augmented wave method [10][11] as implemented in the GPAW code [12][13][14]. A grid of (3,3) for the finite difference stencils have been used together with a grid spacing of 0.18 Å and a minimum of 20

Structural development and energy dissipation in simulated silicon apices

• Samuel Paul Jarvis,
• Lev Kantorovich and
• Philip Moriarty

Beilstein J. Nanotechnol. 2013, 4, 941–948, doi:10.3762/bjnano.4.106

• stability of silicon tip apices by using density functional theory (DFT) calculations. We find that some tip structures - modelled as small, simple clusters - show variations in stability during manipulation dependent on their orientation with respect to the sample surface. Moreover, we observe that

• , more recently, submolecular investigations of planar molecules [11][12], have been revealed. In covalent systems in particular, density functional theory (DFT) calculations have been extremely successful in explaining the fundamental interactions that underpin NC-AFM experiments [2][3][13][14][15][16

• comparison with either the COFI method or DFT calculations, however, is usually required to obtain the same level of confidence. Semiconductors with covalent bonds remain one of the most promising systems for the advancement of atom-by-atom manipulation strategies in multiple dimensions and at room

Adsorption of the ionic liquid [BMP][TFSA] on Au(111) and Ag(111): substrate effects on the structure formation investigated by STM

• Benedikt Uhl,
• Florian Buchner,
• Dorothea Alwast,
• Nadja Wagner and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 903–918, doi:10.3762/bjnano.4.102

• comparable adsorption behavior. This is supported also by the results of density functional theory (DFT) calculations discussed below. These results can be compared with findings reported for other IL adsorption systems. For 1,3-dimethylimidazolium-[TFSA] ([MMIM][TFSA]) and 1-octyl-3-methylimidazolium-[TFSA

• ) [30][31], utilizing a combination of infrared reflection absorption spectroscopy (IRAS) and density functional theory (DFT) calculations. [OMIM][TFSA], which differs from [MMIM][TFSA] only by its longer alkyl chain, showed a coverage dependent adsorption geometry on Au(111): at coverages below 0.6 ML

• Ag(111) substrate. 3) The 2D solid adlayer phases exhibit characteristic patterns consisting of round protrusions and longish protrusions in a ratio of 1:2. Based on comparison with results of previous DFT calculations [26], the round protrusion are identified as cations, with their ring lying flat

Kelvin probe force microscopy of nanocrystalline TiO₂ photoelectrodes

• Alex Henning,
• Gino Günzburger,
• Res Jöhr,
• Yossi Rosenwaks,
• Biljana Bozic-Weber,
• Catherine E. Housecroft,
• Edwin C. Constable,
• Ernst Meyer and
• Thilo Glatzel

Beilstein J. Nanotechnol. 2013, 4, 418–428, doi:10.3762/bjnano.4.49

• rutile TiO2 in ultrahigh vacuum [42]. Using Equation 4 with θ = 0° and measured work-function shifts of ΔΦ = −180 ± 40 mV for the Cu(I) dye and ΔΦ = 150 ± 40 mV for N719 results in 6.3 ± 1.5 D and 5.3 ± 2 D with opposite directions, respectively. The latter value is in the same range as predicted by DFT

• calculations for N719 [38] and N3 [42][63] adsorbed on anatase plane-surface. However, for a complete DSC device the surface dipole may change due to screening by the surrounding electrolyte [64]. Figure 9a depicts the I–V characteristics for three different DSCs, a bare TiO2 solar cell with electrolyte and

In situ monitoring magnetism and resistance of nanophase platinum upon electrochemical oxidation

• Eva-Maria Steyskal,
• Stefan Topolovec,
• Stephan Landgraf,
• Heinz Krenn and
• Roland Würschum

Beilstein J. Nanotechnol. 2013, 4, 394–399, doi:10.3762/bjnano.4.46

• electrochemically induced oxygen adsorption nicely fits with earlier studies of the influence of chemisorbed oxygen on the magnetic susceptibility of Pt [19]. The trend of decreasing magnetic moment is also supported by recent DFT calculations according to which the density of states at the Fermi level of Pt

Catalytic activity of nanostructured Au: Scale effects versus bimetallic/bifunctional effects in low-temperature CO oxidation on nanoporous Au

• Lu-Cun Wang,
• Yi Zhong,
• Haijun Jin,
• Daniel Widmann,
• Jörg Weissmüller and
• R. Jürgen Behm

Beilstein J. Nanotechnol. 2013, 4, 111–128, doi:10.3762/bjnano.4.13

Electronic and transport properties of kinked graphene

• Jesper Toft Rasmussen,
• Tue Gunst,
• Peter Bøggild,
• Antti-Pekka Jauho and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2013, 4, 103–110, doi:10.3762/bjnano.4.12

• transport across the kink lines. We finally consider pseudo-ribbon-based heterostructures and propose that such structures present a novel approach for band gap engineering in nanostructured graphene. Keywords: adsorption and reactivity; curvature effects; DFT calculations; electronic transport; graphene

• barrier that needs to be overcome before the single hydrogen atom sticks to the graphene sheet. Several investigations based on DFT calculations show that atomic hydrogen adsorbs on-top on flat graphene with a barrier about 0.2 eV and binding energy in the range of 0.7–1.0 eV [22][32][33][34]. Thus a

Structural and electronic properties of oligo- and polythiophenes modified by substituents

• Simon P. Rittmeyer and
• Axel Groß

Beilstein J. Nanotechnol. 2012, 3, 909–919, doi:10.3762/bjnano.3.101

• effort in plane-wave codes such as VASP. As we are mainly interested in trends in the local density of states depending on the choice of the substituent, GGA-DFT calculations should be sufficient to reproduce these trends. However, one has to be aware that all absolute values of HOMO–LUMO and band gaps

• already mentioned flattening effect of a growing chain length also found in DFT calculations for other large oligomers [27][31]. It also agrees with the results of Azumi et al. [40], who found a planar structure for the crystalline penta- and heptamer by X-ray diffraction. The calculated bond lengths are

• , since our unit cell only contains at most two thiophene rings, such polarons, which would probably lead to the existence of a band gap, cannot be formed in our periodic DFT calculations. In order to address this issue, larger unit cells are required. Such calculations, which are more time-consuming, are

Strong spin-filtering and spin-valve effects in a molecular V–C₆₀–V contact

• Mohammad Koleini and
• Mads Brandbyge

Beilstein J. Nanotechnol. 2012, 3, 589–596, doi:10.3762/bjnano.3.69

• an isolated adatom on the copper(111) substrate. In the following we will show that the case of vanadium is remarkable. We used spin-polarized pseudopotential DFT calculations with the SIESTA code [28]. Electronic structures have been calculated within a GGA-PBE approximation to the exchange and

Spontaneous dissociation of Co₂(CO)₈ and autocatalytic growth of Co on SiO₂: A combined experimental and theoretical investigation

• Kaliappan Muthukumar,
• Harald O. Jeschke,
• Roser Valentí,
• Evgeniya Begun,
• Johannes Schwenk,
• Fabrizio Porrati and
• Michael Huth

Beilstein J. Nanotechnol. 2012, 3, 546–555, doi:10.3762/bjnano.3.63

• irradiation of selected areas). To our knowledge, no systematic theoretical studies with in-depth DFT calculations on Co2(CO)8 adsorbed on different SiO2 surfaces are available. Therefore, we extent the study using density functional theory (DFT) calculations on slabs representing the various SiO2 surface

• flushed with dry nitrogen and evacuated again for image acquisition. Computational details We performed spin-polarized density functional theory (DFT) calculations within the generalized gradient approximation in the parametrization of Perdew, Burke and Ernzerhof (PBE) [35][36]. Corrections for long-range

• . Partial or full removal of the hydroxyl surface passivation layer leads to an increased driving force for dissociation. This will be discussed in more detail in the the next section in which we present results obtained in the framework of DFT calculations concerning the adsorption behavior and stability

Models of the interaction of metal tips with insulating surfaces

• Thomas Trevethan,
• Matthew Watkins and
• Alexander L. Shluger

Beilstein J. Nanotechnol. 2012, 3, 329–335, doi:10.3762/bjnano.3.37

• contaminated by the surface [7]. Plane-wave density-functional-theory (DFT) calculations employing a periodic metallic-tip model demonstrated that the Cr tip apex interacts most strongly with anions (Cl−) in the surface, and that these ions correspond to protrusions in the image. Thus these experiments and the

• metallic tips with ionic surfaces will help motivate experimental efforts and inform choices of tip material and tip-preparation methods. In this paper we present the results of atomistic DFT calculations performed to investigate the interaction between metal tips and the typical binary ionic surfaces

• interacting with the NaCl surface. We used the exact same system configurations as used in previous plane-wave DFT calculations, employing the VASP code [25] (as described above). The same PBE correlation-exchange functional employed in [7] was used here. The main difference in the model we apply is in the