Carrier multiplication in silicon nanocrystals: ab initio results

• Ivan Marri,
• Marco Govoni and
• Stefano Ossicini

Beilstein J. Nanotechnol. 2015, 6, 343–352, doi:10.3762/bjnano.6.33

• CM effects in systems of isolated and interacting Si-NCs. Structural and electronic properties are calculated within the density functional theory (DFT) using the local density approximation, as implemented in the QuantumESPRESSO package [37]. Energy levels are determined by considering a

X-ray photoelectron spectroscopy of graphitic carbon nanomaterials doped with heteroatoms

• Toma Susi,
• Thomas Pichler and
• Paola Ayala

Beilstein J. Nanotechnol. 2015, 6, 177–192, doi:10.3762/bjnano.6.17

• [192]. However, unambiguous direct evidence for the bonding of phosphorus in graphitic carbon nanomaterials has been lacking. Based on DFT simulations, it is expected that P will predominantly bond to three C neighbors, but buckle significantly out of the surface due its larger atomic radius [97][101

SERS and DFT study of copper surfaces coated with corrosion inhibitor

• Maurizio Muniz-Miranda,
• Francesco Muniz-Miranda and
• Stefano Caporali

Beilstein J. Nanotechnol. 2014, 5, 2489–2497, doi:10.3762/bjnano.5.258

• anticorrosive thin film, the SERS spectra were interpreted with the aid of theoretical calculations based on the density functional theory (DFT) approach. Keywords: copper corrosion; DFT; inhibitor film; 1,2,4-triazole; SERS; Introduction Copper has a long history in a variety of industrial uses due to its

• surfaces are interpreted with the aid of density functional theory (DFT) calculations, which were able to provide useful information on the adsorption of different ligands on metal surfaces, including corrosion inhibitors [12][13][14][15]. Combining spectroscopic and theoretical results leads to the

• substrate. Raman spectra and DFT analysis The investigation on the layer of adsorbed ligands is based on the analysis of the SERS spectra, in addition to a computational approach using the DFT method. This study is complicated by the fact that the molecule in question is a heterocyclic ring that can bind to

Spectroscopic mapping and selective electronic tuning of molecular orbitals in phosphorescent organometallic complexes – a new strategy for OLED materials

• Pascal R. Ewen,
• Jan Sanning,
• Tobias Koch,
• Nikos L. Doltsinis,
• Cristian A. Strassert and
• Daniel Wegner

Beilstein J. Nanotechnol. 2014, 5, 2248–2258, doi:10.3762/bjnano.5.234

• (phosphorescent) triplet emitters both in monomeric and aggregated form [31][32]. We identified a number of occupied and unoccupied frontier orbitals. Comparison with density functional theory (DFT) calculations allows the unambiguous assignment of all MOs from the HOMO–2 to the LUMO+2. We found that the

• the local density of states of the sample. Energy-resolved spectral maps (that visualize the spatial distribution of molecular orbitals) were acquired by measuring dI/dV at a fixed bias as a function of lateral position in constant-current mode. For the DFT calculations shown here, Kohn–Sham molecular

• results from DFT calculations of C1 in the gas phase (Figure 3a) and dI/dV maps of the first monolayer of C1 on Au(111). The theoretical results contain the shapes and energies of five molecular orbitals with respect to EF . While only one MO (HOMO–1) is exclusively localized at the Pt atom, all other

UHV deposition and characterization of a mononuclear iron(III) β-diketonate complex on Au(111)

• Irene Cimatti,
• Silviya Ninova,
• Valeria Lanzilotto,
• Luigi Malavolti,
• Luca Rigamonti,
• Brunetto Cortigiani,
• Matteo Mannini,
• Elena Magnano,
• Federica Bondino,
• Federico Totti,
• Andrea Cornia and
• Roberta Sessoli

Beilstein J. Nanotechnol. 2014, 5, 2139–2148, doi:10.3762/bjnano.5.223

• regular domains characterized by a flat morphology and height of ≈0.3 nm. Along with these domains, tetra-lobed features adsorbed on the kinks of the herringbone were also observed. DFT-simulated images of the pristine molecule and its possible decomposition products allowed to assess the partial

• ) in octahedral environment were observed. Keywords: Au(111); β-diketonate complexes; DFT; STM; thin films; UPS; XMCD; XPS; Introduction A renewed interest in mononuclear metal complexes has recently arisen due to the observation that systems of this class can behave as single molecule magnets (SMMs

• . As for the Fe 2p region, the signal is detectable but quite noisy at saturation coverage, and practically negligible at t1. Therefore, no useful information about the Fe oxidation state could be retrieved. STM and DFT characterization Spectroscopic characterization indicates that Fe(dpm)3 adsorbs on

Electronic and electrochemical doping of graphene by surface adsorbates

• Hugo Pinto and
• Alexander Markevich

Beilstein J. Nanotechnol. 2014, 5, 1842–1848, doi:10.3762/bjnano.5.195

• demonstrated for various atomic and molecular adsorbates. Electropositive elements that easily donate their outer shell electrons are expected to be n-type dopants. Indeed, density functional theory (DFT) calculations predicted group I–III metals to be efficient electron donors for graphene [25][26][27][28

• experimental results, DFT calculations have shown that K atoms act as electron donors [25][26][27][28]. Electronic band structure calculations show that adsorption of a K atom on graphene results in the shift of the Fermi level above the Dirac point, indicating the n-type doping of graphene, Figure 3a

• graphene was studied by synchrotron-based high resolution photoemission spectroscopy (PES) [35]. The increase of the graphene work function due to the deposition of F4-TCNQ (Figure 5) suggests that there is an electron transfer from graphene to the molecule. In agreement with PES measurements DFT

Silicon and germanium nanocrystals: properties and characterization

• Ivana Capan,
• Alexandra Carvalho and
• José Coutinho

Beilstein J. Nanotechnol. 2014, 5, 1787–1794, doi:10.3762/bjnano.5.189

• even the smallest particles that were realized experimentally (about 1000 atoms for ca. 3 nm). Such sizes are close to the practical limits of present-day first-principles density functional theory implementations. Various full-DFT implementations by using localized basis sets such as Aimpro [17][44

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

• antiferromagnetic transition pressures. Mapping DFT energies onto a simple-spin Hamiltonian shows both the intra- and inter-chain coupling to be antiferromagnetic, with the latter coupling constant being two orders of magnitude smaller than the former, suggesting the MIL-47(V) to present quasi-1D behavior. The

• dispersion along the the direction of the VO6 chains, similar as for other quasi-1D materials. Keywords: band structure; density functional theory (DFT); low-dimensional electronics; metal-organic frameworks (MOFs); MIL-47; Introduction Metal-organic frameworks (MOFs) present a class of materials located

Liquid fuel cells

• Grigorii L. Soloveichik

Beilstein J. Nanotechnol. 2014, 5, 1399–1418, doi:10.3762/bjnano.5.153

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

• host–guest chemistry. In the solid state, the trans structure was calculated to be lower in energy than the cis isomer. However, the dynamic change from trans to cis conformation was studied by DFT calculation and the energy barrier was found to be 13 kcal/mol and 20 kcal/mol for the reverse. The path

Magnesium batteries: Current state of the art, issues and future perspectives

• Rana Mohtadi and
• Fuminori Mizuno

Beilstein J. Nanotechnol. 2014, 5, 1291–1311, doi:10.3762/bjnano.5.143

• study of borohydride-based solid state electrolytes was reported by Higashi et al. [37]. Guided by their first-principles calculations based on density functional theory (DFT), they experimentally investigated the conduction of magnesium ions in both Mg(BH4)2 and Mg(BH4)(NH2). The selection of these

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

• seen experimentally (see Figure 2 and [41]) would naturally fall in with the graphene grain boundaries, but this has not been observed. The role of inter-impurity interactions has been considered as an alternative, through both tight binding [43] and DFT [39][44] formalisms, although with differing

• , 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

• efficiency of the catalyst. In addition, platinum was deemed suitable because substantial simulation work has been done on this system before. Much work has been done in recent years by using mostly quantum mechanical density functional theory (DFT) to study adsorbate energetics and geometries on many

• 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

• ]. Theoretical calculations based on density functional theory (DFT) can be used to simulate the details in ELNES and to fundamentally predict the atomic and the electronic structure. Depending on the atomic potentials defined in the calculation, methods based on the band theory, the molecular orbitals or the

• 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

• mechanical simulation of extended systems even by means of density functional theory (DFT) has to assume a regular lattice and can treat only small unit cells [6][7][8]. Consequently, the resulting structure is also regular [8]. If one, as in the present case, can expect that the structure is irregular, i.e

• 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

Volcano plots in hydrogen electrocatalysis – uses and abuses

• Paola Quaino,
• Fernanda Juarez,
• Elizabeth Santos and
• Wolfgang Schmickler

Beilstein J. Nanotechnol. 2014, 5, 846–854, doi:10.3762/bjnano.5.96

• energies calculated by density functional theory (DFT). These are quite reliable for hydrogen adsorption – more so than experimental values – with an estimated error of ±0.1 eV. We have calculated these adsorption energies for a fair number of densely-packed metal surfaces, mostly fcc(111). In those cases

• , in which we considered the same metals, we obtained the same values as Nørskov et al. [7] within the usual DFT error. In contrast, the experimental values for the reaction rates measured by different groups sometimes vary by two orders of magnitude. The sources for our data are given in the appendix

• better sample preparation. Discussion Our group has developed its own theory of hydrogen electrocatalysis, based on a model Hamiltonian, quantum statistics and DFT, which we have reviewed in [8]. From our work we have derived three rules for a good catalyst: It should follow Sabatier’s principle, ΔG ≈ 0

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

Visible light photooxidative performance of a high-nuclearity molecular bismuth vanadium oxide cluster

• Johannes Tucher and
• Carsten Streb

Beilstein J. Nanotechnol. 2014, 5, 711–716, doi:10.3762/bjnano.5.83

• aerobic conditions [48]. This hypothesis is currently being investigated using TD-DFT and transient absorption spectroscopy methods. Identification of hydroxyl radicals as intermediates To gain further insight into the reaction mechanism involved in the photooxidation of indigo by 1, homogeneous dye

Nanostructure sensitization of transition metal oxides for visible-light photocatalysis

• Hongjun Chen and
• Lianzhou Wang

Beilstein J. Nanotechnol. 2014, 5, 696–710, doi:10.3762/bjnano.5.82

• interestingly, valence electrons may be directly excited from graphene into the CB of TiO2 under visible light illumination, so that graphene may be used as a photosensitizer. The authors also investigated the graphene–g-C3N4 interface by hybrid functional DFT methods and found a band gap (around 70 meV

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

• that restrict the description of the system to the finite model chosen. In this work, we focus on finite systems approaches from quantum chemistry for treating electrochemical phenomena. These methods, especially in the framework of density functional theory (DFT), have in recent decades been applied

• 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

• necessity and possibility to carry out constant-μ calculations, the authors lay out the theoretical underpinning in the framework of linear response theory and variational DFT schemes. They describe a variational procedure in which the Kohn–Sham equations are solved in the framework of a Grand-Potential

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

• applications. Calculation Theoretically, the band structure of the Ag2CrO4 is also calculated by density function theory (DFT) (Figure 6). As shown in the band structure plots, the calculated band gap energy of Ag2CrO4 is 1.37 eV, which is lower than the experimental values, which is due to the well-known

• limitation of DFT calculation [63][64]. The electronic structure of Ag2CrO4 indicates that the valence band mainly consists of occupied Ag 4d and O 2p orbitals, and the conduction band mainly comes from the empty Cr 3d orbital, which means that Cr makes an important contribution to the bottom of the

• 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

• theory (DFT); heterofullerene; Introduction The continuous dependence on fossil fuel combustion for the generation of energy has dramatically increased the atmospheric CO2 concentrations over the last century. Despite concerns for global climatic changes and many attempts to sustainably generate energy

• . 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

Uncertainties in forces extracted from non-contact atomic force microscopy measurements by fitting of long-range background forces

• Adam Sweetman and
• Andrew Stannard

Beilstein J. Nanotechnol. 2014, 5, 386–393, doi:10.3762/bjnano.5.45

• tip–sample interaction is usually modelled (for example using density functional theory (DFT) [1]) as the interaction between a small cluster of atoms (representing the tip) and a slab of surface atoms. In order to extract the short-range force from the frequency shift measurement, however, the

• models [1][6][11][12][13][14]. Results are then often compared to DFT modelling with subsequent interpretation of the data requiring accuracies on the order of a few 100’s [1][13], or sometimes even 10’s [12], of piconewtons. Interestingly, this technique has sometimes been applied in instances where

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

• = 1.3 eV, r0 = 2.2 Å, a = 2.0 Å−1) binding one of the carboxylic oxygens to the outermost tip apex atom. The parameters of this potential have been determined with the help of DFT simulations presented in [23]. The molecule–surface interaction is described as a set of individual atom–surface potentials