Different procedures to obtain atom condensed Fukui functions are described. It is shown how the resulting values may differ depending on exact approach functions. The function can be computed using either fragment of molecular response or approach. two approaches nonequivalent; only latter corresponds in general with a population difference expression. Mulliken does not depend taken but has some computational drawbacks. different expressions tested for wide set molecules. In practice one...

It is shown that molecular electrostatic potentials obtained from iterative or self-consistent Hirshfeld atomic point charges agree remarkably well with the ab initio computed potentials. The scheme performs nearly as potential derived charges, having advantage of allowing definition atom in molecule, rather than just yielding charges. quality for computing examined a large set molecules and compared to other commonly used techniques population analysis.

Abstract Using multicentre delocalization indices, the ring current maps of a large set polycyclic aromatic hydrocarbons (PAH) are reconstructed and compared with ab initio computations same in pseudo‐π version ipsocentric approach to magnetic response. The quality comparison indicates that both approaches capture information about nature PAH. Aromaticity as global property, requires knowledge more than single circuits, but present results suggest no need introduce “multidimensional...

Significance The empirically observed transferability of functional groups is shown to follow from Kohn’s nearsightedness principle for electron density. To show this, we analytically calculated and analyzed the softness kernel molecules. relevance this work touches on physics (the principle), molecular chemistry materials science (chemical similarity), computer (machine-learning approaches pharmaceutical design).

Abstract The local aromaticity of benzenoid rings is examined by means the Polansky index (P) and generalized population analysis (GPA). results are found to agree very well with recently published circuit‐condensed ring currents magnetic‐energetic indices, but no correlation nucleus independent chemical shifts (NICS). This usually seen as a manifestation more general multidimensional nature aromaticity. paper examines sources for observed correlations, showing that some indices give...

Abstract The aromaticity and local‐aromaticity of a large set polycyclic aromatic hydrocarbons (PAHs) is studied using multicenter delocalization indices from generalized population analysis the popular nucleus independent chemical shift (NICS) index. A method for fast computation NICS values introduced, so‐called pseudo‐π‐method. detailed examination made multidimensional nature aromaticity. lack good correlation between reported grounds discussed. It shown through thorough statistical that...

We analyse the electronic structure and aromaticity of graphene nanoribbons carbon nanotubes through a series delocalisation geometry analysis methods. In particular, six-centre index (SCI) is found to be in good agreement with mean bond length (MBL) ring dispersion (RBD) descriptors. Based on DFT periodic calculations, three distinct classes patterns have been for armchair nanoribbons, appearing periodically as width ribbon increased. The periodicity band gap related these patterns. Also,...

A new selection rule for transmission under small voltage molecular electronic devices consisting of alternant hydrocarbons is established, based on curly arrow drawings the displacement electrons through conjugated system molecule. If from one contact atom to other can be drawn, possible. not, then no will take place. This simple, back envelope ansatz allows determination quantum interferences a wide range experimentally studied molecules (linear polyenes, benzenoids, cross-conjugated...

We show in this work that conjugated π-electron molecular chains can, quite specific and understood circumstances, become more conductive the longer they get, contradiction to what would be expected intuitively. The analysis, done framework of source sink potential method, supported by detailed transmission calculations, begins defining “relative transmission,” an inherent measure conduction. This, turn, for hydrocarbons, is related a simple orbital expression—the ratio secular determinants...

In the first paper of this series, authors derived an expression for interaction energy between two reagents in terms chemical reactivity indicators that can be from density functional perturbation theory. While negative energies explain reactivity, is often more simply explained using "|dμ| big good" rule or maximum hardness principle. Expressions change potential (μ) and when interact are derived. A partial justification principle appear reappear hardness, but with opposite sign.

The Woodward-Hoffmann rules for pericyclic reactions, a fundamental set of reactivity in organic chemistry, are formulated the language conceptual density functional theory (DFT). DFT provides an elegant framework to introduce chemical concepts and principles quantitative manner, partly because it is without explicit reference wave function, on whose symmetry properties [J. Am. Chem. Soc. 87, 395 (1965)] based. We have studied initial hardness response using model reaction profile two...

The degree of aromaticity six-membered monoheterocycles with IV-VI group heteroatoms (C(6)H(5)X, where X = SiH, GeH, N, P, As, O(+), S(+), Se(+)) was analyzed using the results ab initio calculations at MP2/cc-pvtz level. Values common indices including those based on electronic delocalization properties, structural-dynamic features and magnetic properties all indicate high considered heterocycles. A decrease in is observed increasing atomic number heteroatom, except case pyrylium cation....

We assess the predictive accuracy of perturbation theory based estimates changes in covalent bonding due to linear alchemical interpolations among molecules. have investigated σ hydrogen, as well and π between main-group elements, occurring small sets iso-valence-electronic molecules with elements drawn from second fourth rows p-block periodic table. Numerical evidence suggests that first order Taylor expansions potentials can achieve high if (i) interpolation is vertical (fixed geometry),...

We explore a new strategy to tune the conductivity of molecular electronic devices: captodative substitution. demonstrate that careful design such substitution schemes on benzene parental structure can enhance by almost an order magnitude under small bias. Once this has been established, we apply it wires and enables unprecedented anti-Ohmic whose increases with length. Overall, approach provides very promising pathway toward full chemical control molecules which opens up possibility...

The chemical importance of the linear response kernel from conceptual Density Functional Theory (DFT) is investigated for some σ and π aromatic anti-aromatic systems. effect ring size studied by looking at well known molecules different sizes, showing that capable correctly classifying quantifying aromaticity five- to eight-membered molecules. splitting in contributions introduced its significance illustrated using σ-aromatic also predicts transition states Diels–Alder reaction acetylene...

Abstract In a recent contribution, we examined the effect of 10‐ and 14‐center circuits on nucleus‐independent chemical shifts NICSs using multicenter bond indices (MCBIs) (Fias et al., J Comput Chem 2008, 29, 358). this study, nonlocal contributions to NICS are further investigated for larger set polycyclic aromatic hydrocarbons (PAHs). To achieve this, predicted MCBI compared with ab initio results. The central ring perylene‐ benzo‐[ghi]perylene‐like fragments coronene appear have other...

The atom-atom polarizability and the transmission probability at Fermi level, as obtained through source-and-sink-potential method for every possible configuration of contacts simultaneously, are compared polycyclic aromatic compounds. This comparison leads to conjecture that a positive is necessary condition take place in alternant hydrocarbons without non-bonding orbitals relative different configurations can be predicted by analyzing corresponding polarizability. A theoretical link...

Tuning the band gap of graphene nanoribbons by chemical edge functionalisation is a promising approach towards future electronic devices based on graphene. The closely related to aromaticity distribution and therefore tailoring patterns rational way for controlling gap. In present work, it shown how three distinct classes already found armchair can be rationally tuned modify their arrangement structure are studied using DFT calculations through series delocalisation geometry analysis...

The linear response kernel is used to gain insight into the aromatic behavior of less classical metal E4(2-) and CE4(2-) (E = Al, Ga) clusters. effect systematic replacement aluminum atoms in Al4(2-) CAl4(2-) by germanium studied using, Al3Ge-, Al2Ge2, AlGe3+, Ge4(2+), CAl3Ge-, CAl2Ge2, CAlGe3+, CGe4(2+). results are compared with values delocalization index (δ(1,3)) nucleus independent chemical shifts (NICS(zz)). Unintegrated plots response, computed for first time on molecules, analyze...

In silico design of new molecules and materials with desirable quantum properties by high-throughput screening is a major challenge due to the high dimensionality chemical space. To facilitate its navigation, we present unification coordinate composition space in terms alchemical normal modes (ANMs) which result from second order perturbation theory. ANMs assume predominantly smooth nature form basis compounds can be expanded identified. We showcase use for energetics isoelectronic series...

In this work, electrical currents through nanographenes, a class of alternant hydrocarbons also known as polycyclic aromatic hydrocarbons, in molecular junctions under small bias are explored. We illustrate that when the π-current dominates, is, no quantum interference takes place, current prefers direction shortest bond (the with highest double character) upon entering molecule from contacts. As such, idea electrons propagating bonds contact to contact, originating curly arrow drawings used...