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Electron localization and delocalization in open-shell molecules

Xavier Fradera, Miquel Solà
2002 Journal of Computational Chemistry  
Localization and delocalization indices derived in the framework of the quantum Atoms in Molecules theory have recently been used to analyze the electron-pair structure of closed-shell molecules.  ...  Here we report calculations of localization and delocalization indices for open-shell molecules at the Hartree-Fock (HF) level. Several simple doublet and triplet radical molecules are studied.  ...  In summary, localization and delocalization indices have proven to be very useful for the detailed analysis of the electronpair structure of open-shell molecules.  ... 
doi:10.1002/jcc.10141 pmid:12214317 fatcat:yfubgfavprddjjaoq7qyh6sh4q

The calculation of electron localization and delocalization indices at the Hartree-Fock, density functional and post-Hartree-Fock levels of theory

Jordi Poater, Miquel Solà, Miquel Duran, Xavier Fradera
2002 Theoretical Chemistry accounts  
Localization, kðAÞ, and delocalization indices, dðA; BÞ, as defined in the atoms in molecules theory, are a convenient tool for the analysis of molecular electronic structure from an electron-pair perspective  ...  In summary, approximate DFT and CI localization and delocalization indices are easy to calculate and can be useful in the analysis of molecular electronic structure; however, one should take into account  ...  Covalent nonpolar open-shell interactions.  ... 
doi:10.1007/s00214-002-0356-8 fatcat:mujvi6w4xjazvf4rkequxwbcki

Singlet/Triplet State Anti/Aromaticity of CyclopentadienylCation: Sensitivity to Substituent Effect

Milovan Stojanović, Jovana Aleksić, Marija Baranac-Stojanović
2021 Chemistry  
The extent of (anti)aromaticity was evaluated by using structural (HOMA), magnetic (NICS), energetic (ISE), and electronic (EDDBp) criteria.  ...  It is well known that singlet state aromaticity is quite insensitive to substituent effects, in the case of monosubstitution.  ...  The weakly delocalized charge density in the closed-shell state becomes (almost) equally delocalized on each carbon atom in open-shell states, and spin density is unsymmetrically distributed in two allyl-like  ... 
doi:10.3390/chemistry3030055 fatcat:xuvy4argwvgzler7fxmf4p6ij4

Localization of inner-shell photoelectron emission and interatomic Coulombic decay in Ne2

K Kreidi, T Jahnke, Th Weber, T Havermeier, R E Grisenti, X Liu, Y Morisita, S Schössler, L Ph H Schmidt, M Schöffler, M Odenweller, N Neumann (+20 others)
2008 Journal of Physics B: Atomic, Molecular and Optical Physics  
of the Ne_2 and an emission of the ICD electron from a localized site.  ...  The molecular frame angular distributions of the photoelectron and the ICD electron show distinct, asymmetric features, which imply localization of the K-vacancy created at one of the two atomic sites  ...  We are grateful also to S Stoychev, A Kuleff, B Averbukh and L S Cederbaum for stimulating discussion. KK and TW acknowledge support by DESY. XJL acknowledges support by JSPS.  ... 
doi:10.1088/0953-4075/41/10/101002 fatcat:jxv57weuu5c2vd26ytf3ybwyca

Double core–hole electron spectroscopy for open-shell molecules: Theoretical perspective

Motomichi Tashiro, Masahiro Ehara, Kiyoshi Ueda
2010 Chemical Physics Letters  
We have theoretically investigated the double core-hole (DCH) states of the open-shell molecules and examined the possibility of DCH spectroscopy by means of X-ray two-photon photoelectron spectroscopy  ...  Energies of many DCH states were obtained by the CASSCF calculations and the generalized intra- and interatomic relaxation energies were evaluated.  ...  The deviations of these orbital energies from those in Table 1 (canonical ROHF) are 0.06 and 0.38 eV for CN and 0.56 eV for O 2 .  ... 
doi:10.1016/j.cplett.2010.07.046 fatcat:xz47xsfyqfherm5qzy2jfupq5q

Delocalization errors in a hubbard-like model: Consequences for density-functional tight-binding calculations of molecular systems

Marcus Lundberg, Yoshio Nishimoto, Stephan Irle
2011 International Journal of Quantum Chemistry  
In addition to cationic dimers, we discuss the effects of the delocalization error for asymmetric systems, bond dissociation of neutral molecules, and the description of mixed valence transition metal  ...  However, in most cases the localized state will be favored by spin polarization, fragment repulsion, solvent effects and large reorganization energies, in analogy to density functional theory (DFT), from  ...  The work was in part supported by a CREST (Core Research for Evolutional Science and Technology) grant in the Area of High Performance Computing for Multi-scale and Multi-physics Phenomena from the Japan  ... 
doi:10.1002/qua.23178 fatcat:77gbo6xb6zgjvlemiad3oi3tri

Application of spin-restricted open-shell Kohn–Sham method to atomic and molecular multiplet states

Michael Filatov, Sason Shaik
1999 Journal of Chemical Physics  
A recently proposed spin-restricted open-shell Kohn-Sham ͑ROKS͒ method is applied to investigate various atomic and molecular multiplet states.  ...  A wide range of multiplets is considered: multiplet terms for which the spin-restricted open-shell theory of Roothaan applies, as well as state situations which cannot be described by Roothaan's theory  ...  /delocalization of open-shell orbitals.  ... 
doi:10.1063/1.477941 fatcat:o6k4wvyzt5fkvccdtif37pn7ku

Bis(aminoaryl) Carbon-Bridged Oligo(phenylenevinylene)s Expand the Limits of Electronic Couplings

Paula Mayorga Burrezo, Nai-Ti Lin, Koji Nakabayashi, Shin-ichi Ohkoshi, Eva M. Calzado, Pedro G. Boj, María A. Díaz García, Carlos Franco, Concepciò Rovira, Jaume Veciana, Michael Moos, Christoph Lambert (+4 others)
2017 Angewandte Chemie International Edition  
In their dication states, the antiferromagnetic coupling is progressively tuned with size from quinoidal closed-shell to open-shell biradicals.  ...  Oligo(phenylenevinylene) (OPVs) compounds are stellar molecules in organic electronics. [1] Recently their fused and planar derivatives have been prepared by inserting carbon bridges between the phenylene  ...  This work is partially supported by Grant-in-Aid for Scientific Research (16H04106 to HTand 15H05754 to EN) and the Strategic Promotion of Innovative Research, JST (to EN) from MEXT,Japan.  ... 
doi:10.1002/anie.201610921 pmid:28140501 fatcat:sdjekqxwhne7flc4xlzf2kwxgi

Bis(aminoaryl) Carbon-Bridged Oligo(phenylenevinylene)s Expand the Limits of Electronic Couplings

Paula Mayorga Burrezo, Nai-Ti Lin, Koji Nakabayashi, Shin-ichi Ohkoshi, Eva M. Calzado, Pedro G. Boj, María A. Díaz García, Carlos Franco, Concepciò Rovira, Jaume Veciana, Michael Moos, Christoph Lambert (+4 others)
2017 Angewandte Chemie  
In their dication states, the antiferromagnetic coupling is progressively tuned with size from quinoidal closed-shell to open-shell biradicals.  ...  Oligo(phenylenevinylene) (OPVs) compounds are stellar molecules in organic electronics. [1] Recently their fused and planar derivatives have been prepared by inserting carbon bridges between the phenylene  ...  This work is partially supported by Grant-in-Aid for Scientific Research (16H04106 to HTand 15H05754 to EN) and the Strategic Promotion of Innovative Research, JST (to EN) from MEXT,Japan.  ... 
doi:10.1002/ange.201610921 fatcat:jgfoi4zqc5hcvezqlhp4unbtvy

Second-order atomic Fukui indices from the electron-pair density in the framework of the atoms in molecules theory

Xavier Fradera, Miquel Solà
2003 Journal of Computational Chemistry  
We show how second-order atomic Fukui indices can be used to analyze the effects of electron loss or gain in several molecules from an electron pair point of view.  ...  Atomic Fukui indices, which are obtained from the electron density, have been previously shown to be useful in predicting which atoms in a molecule are most likely to suffer nucleophilic, electrophilic  ...  CN and NO are the only neutral open-shell molecules, with 13 and 15 electrons, respectively (seeTables 1e and 1f).  ... 
doi:10.1002/jcc.10396 pmid:14696078 fatcat:gb6y7prvfvdtfmsdp7t25xp55q

Recognizing a triple bond between main group atoms

José Molina Molina, J. A. Dobado, George L. Heard, Richard F. W. Bader, Markku R. Sundberg
2001 Theoretical Chemistry accounts  
The electron pair density, in conjunction with the theory of an atom in a molecule, enables one to unambiguously determine the nature of the bonding between the gallium atoms in bent [HGa-GaH] 2) .  ...  model of the electron pair.  ...  For a closed-shell molecule, the result is a localized a,b pair.  ... 
doi:10.1007/s002140000232 fatcat:drqhqy57png2xmnl42egwpja3u

Insights into Current Limitations of Density Functional Theory

A. J. Cohen, P. Mori-Sanchez, W. Yang
2008 Science  
Density functional theory of electronic structure is widely and successfully applied in simulations throughout engineering and sciences.  ...  However, for many predicted properties, there are spectacular failures that can be traced to the delocalization error and static correlation error of commonly used approximations.  ...  At present, the accurate calculation of closed-shell singlets is not always possible in DFT because of static correlation error, which has led to the routine use of broken-symmetry open-shell singlets.  ... 
doi:10.1126/science.1158722 pmid:18687952 fatcat:flgyueknkjhndogb2z6e5p3ose

Exploring the electron density localization in single MoS2 monolayers by means of a localize-electrons detector and the quantum theory of atoms in molecules

Yosslen Aray
2017 AIP Advances  
representation of localized pairs in atoms and molecules. 21 The single particle kinetic energy provides the electronic localization of electron pairs in molecules, and hence its associated momentumP  ...  electrons are spatially confined in pairs, as in the case of bonding regions and atomic shells 21, 24 and provides a direct three-dimensional representation of bonding interactions in molecules.  ... 
doi:10.1063/1.4999620 fatcat:oab5t6hfdzczhjszwrgpl3r3iu

A sodium atom in a large water cluster: Electron delocalization and infrared spectra

Lukasz Cwiklik, Udo Buck, Waldemar Kulig, Piotr Kubisiak, Pavel Jungwirth
2008 Journal of Chemical Physics  
We follow the dynamics of the atom-cluster interaction and the delocalization of the valence electron of sodium together with changes in the electron binding energy.  ...  This electron tends to be shared by the nascent sodium cation and the water cluster.  ...  Acknowledgment Support by the Czech Ministry of Education and the Czech Science Foundation (projects LC512 and 202/06/0286) is gratefully acknowledged.  ... 
doi:10.1063/1.2902970 pmid:18433208 fatcat:ngvvfu2wnvb6nbq6zewuuwqxxm

B14: An all-boron fullerene

2012 Journal of Chemical Physics  
Chemical bonding analysis given by AdNDP reveals that the B 14 cage is an all-boron fullerene with 18 delocalized σ -electrons following the 2(n+1) 2 rule of spherical aromaticity.  ...  electronic structure.  ...  As shown in Figure 3(b) , the AdNDP analysis reveals twelve localized 2c-2e σ -bonds, eight delocalized 3c-2e σ -bonds, and one delocalized 8c-2e σ -bond in the B 14 cage.  ... 
doi:10.1063/1.3692183 pmid:22423832 fatcat:kvuy3o346zgvxifine6mirvctu
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