scholarly journals Theoretical Study on the Difference in Electron Conductivity of a One-Dimensional Penta-Nickel(II) Complex between Anti-Ferromagnetic and Ferromagnetic States—Possibility of Molecular Switch with Open-Shell Molecules

Molecules ◽  
2019 ◽  
Vol 24 (10) ◽  
pp. 1956
Author(s):  
Yasutaka Kitagawa ◽  
Hayato Tada ◽  
Iori Era ◽  
Takuya Fujii ◽  
Kazuki Ikenaga ◽  
...  
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Open Shell ◽  
Molecular Switch ◽  
Electron Conductivity ◽  
Molecular Wire ◽  
Functional Theory ◽  
One Dimensional ◽  
Atom Chain ◽  
The Difference

The electron conductivity of an extended metal atom chain (EMAC) that consisted of penta-nickel(II) ions bridged by oligo-α-pyridylamino ligands was examined by density functional theory (DFT) and elastic scattering Green’s functions (ESGF) calculations. The calculated results revealed that an intramolecular ferromagnetic (FM) coupling state showed a higher conductivity in comparison with an anti-ferromagnetic (AFM) coupling state. The present results suggest the potential of the complex as a molecular switch as well as a molecular wire.

Theoretical Study of Atoms Filled in Carbon Nanotubes

2016 ◽  
Vol 13 (10) ◽  
pp. 6974-6977
Author(s):  
Shuwen Cui ◽  
Weiwei Liu ◽  
Xiaosong Wang
Keyword(s):  
Carbon Nanotubes ◽  
First Principles ◽  
Density Functional ◽  
Theoretical Study ◽  
Local Density ◽  
First Principles Calculations ◽  
Functional Theory ◽  
One Dimensional ◽  
Local Density Functional Theory ◽  
Foreign Materials

The nano-sized quasi-one dimensional hollow cores of carbon nanotubes make it possible for them to be filled with and wetted by foreign materials. With C, S and Se atoms as example, we have studied the filling and wetting of these atoms into carbon nanotubes from local density functional theory in first principles calculations. The results suggest that the effect of nanotube length is negligible when it exceeds 3.6 Å, there is a relation between nanotube diameter and filling and wetting. Our studies would be important implications for the further use of carbon nanotubes.

Theoretical Study on Open-Shell Nonlinear Optical Systems

2004 ◽  
Vol 846 ◽  
Author(s):  
Masayoshi Nakano ◽  
Ryohei Kishi ◽  
Nozomi Nakagawa ◽  
Tomoshige Nitta ◽  
Takashi Kubo ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Nonlinear Optical ◽  
Control Parameter ◽  
Theoretical Study ◽  
Open Shell ◽  
Optical Systems ◽  
Dft Methods ◽  
Functional Theory ◽  
Diradical Character

ABSTRACTThe static second hyperpolarizabilities (γ) of open-shell organic nonlinear optical (NLO) systems composed of singlet diradical molecules are investigated using ab initio molecular orbital (MO) and density functional theory (DFT) methods. It is found that neutral singlet diradical systems with intermediate diradical characters tend to enhance γ as compared to those with small and large diradical characters. This suggests that the diradical character is a novel control parameter of γ for singlet diradical systems.

scholarly journals Quasi-1D XY antiferromagnet Sr2Ni(SeO3)2Cl2 at Sakai-Takahashi phase diagram

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
E. S. Kozlyakova ◽  
A. V. Moskin ◽  
P. S. Berdonosov ◽  
V. V. Gapontsev ◽  
S. V. Streltsov ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Long Range ◽  
Density Functional ◽  
Uniaxial Anisotropy ◽  
Exchange Interactions ◽  
Spin Liquid ◽  
Functional Theory ◽  
One Dimensional ◽  
Ordered Phases ◽  
Experimental Findings

AbstractUniform quasi-one-dimensional integer spin compounds are of interest as a potential realization of the Haldane conjecture of a gapped spin liquid. This phase, however, has to compete with magnetic anisotropy and long-range ordered phases, the implementation of which depends on the ratio of interchain J′ and intrachain J exchange interactions and both uniaxial D and rhombic E single-ion anisotropies. Strontium nickel selenite chloride, Sr2Ni(SeO3)2Cl2, is a spin-1 chain system which passes through a correlations regime at Tmax ~ 12 K to long-range order at TN = 6 K. Under external magnetic field it experiences the sequence of spin-flop at Bc1 = 9.0 T and spin-flip transitions Bc2 = 23.7 T prior to full saturation at Bsat = 31.0 T. Density functional theory provides values of the main exchange interactions and uniaxial anisotropy which corroborate the experimental findings. The values of J′/J = 0.083 and D/J = 0.357 place this compound into a hitherto unoccupied sector of the Sakai-Takahashi phase diagram.

scholarly journals Theoretical Study of Zirconium Isomorphous Substitution into Zeolite Frameworks

Molecules ◽  
2019 ◽  
Vol 24 (24) ◽  
pp. 4466
Author(s):  
Duichun Li ◽  
Bin Xing ◽  
Baojun Wang ◽  
Ruifeng Li
Keyword(s):  
Acid Site ◽  
Density Functional ◽  
Theoretical Study ◽  
Atomic Radius ◽  
Acid Sites ◽  
Isomorphous Substitution ◽  
Dispersion Correction ◽  
Brønsted Acidity ◽  
Functional Theory ◽  
Brönsted Acidity

Systematic periodic density functional theory computations including dispersion correction (DFT-D) were carried out to determine the preferred location site of Zr atoms in sodalite (SOD) and CHA-type topology frameworks, including alumino-phosphate-34 (AlPO-34) and silico-alumino-phosphate-34 (SAPO-34), and to determine the relative stability and Brönsted acidity of Zr-substituted forms of SOD, AlPO-34, and SAPO-34. Mono and multiple Zr atom substitutions were considered. The Zr substitution causes obvious structural distortion because of the larger atomic radius of Zr than that of Si, however, Zr-substituted forms of zeolites are found to be more stable than pristine zeolites. Our results demonstrate that in the most stable configurations, the preferred favorable substitutions of Zr in substituted SOD have Zr located at the neighboring sites of the Al-substituted site. However, in the AlPO-34 and SAPO-34 frameworks, the Zr atoms are more easily distributed in a dispersed form, rather than being centralized. Brönsted acidity of substituted zeolites strongly depends on Zr content. For SOD, substitution of Zr atoms reduces Brönsted acidity. However, for Zr-substituted forms of AlPO-34 and SAPO-34, Brönsted acidity of the Zr-O(H)-Al acid sites are, at first, reduced and, then, the presence of Zr atoms substantially increased Brönsted acidity of the Zr-O(H)-Al acid site. The results in the SAPO-34-Zr indicate that more Zr atoms substantially increase Brönsted acidity of the Si-O(H)-Al acid site. It is suggested that substituted heteroatoms play an important role in regulating and controlling structural stability and Brönsted acidity of zeolites.

scholarly journals Theoretical Study of the Structures of 4-(2,3,5,6-Tetrafluoropyridyl)Diphenylphosphine Oxide and Tris(Pentafluorophenyl)Phosphine Oxide: Why Does the Crystal Structure of (Tetrafluoropyridyl)Diphenylphosphine Oxide Have Two Different P=O Bond Lengths?

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2778
Author(s):  
Joseph R. Lane ◽  
Graham C. Saunders
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonding ◽  
Phosphine Oxide ◽  
Density Functional ◽  
Lone Pair ◽  
Diphenylphosphine Oxide ◽  
Functional Theory ◽  
Weak Hydrogen Bonding ◽  
Independent Molecules ◽  
The Difference

The crystal structure of 4-(2,3,5,6-tetrafluoropyridyl)diphenylphosphine oxide (1) contains two independent molecules in the asymmetric unit. Although the molecules are virtually identical in all other aspects, the P=O bond distances differ by ca. 0.02 Å. In contrast, although tris(pentafluorophenyl)phosphine oxide (2) has a similar crystal structure, the P=O bond distances of the two independent molecules are identical. To investigate the reason for the difference, a density functional theory study was undertaken. Both structures comprise chains of molecules. The attraction between molecules of 1, which comprises lone pair–π, weak hydrogen bonding and C–H∙∙∙arene interactions, has energies of 70 and 71 kJ mol−1. The attraction between molecules of 2 comprises two lone pair–π interactions, and has energies of 99 and 100 kJ mol−1. There is weak hydrogen bonding between molecules of adjacent chains involving the oxygen atom of 1. For one molecule, this interaction is with a symmetry independent molecule, whereas for the other, it also occurs with a symmetry related molecule. This provides a reason for the difference in P=O distance. This interaction is not possible for 2, and so there is no difference between the P=O distances of 2.

POSSIBILITY OF MOLECULAR-SWITCH WITH CONTROLLED HYDROGEN BOND: UTILITY OF COMBINATION OF 2,2′-BIIMIDAZOLE AND REDOX-ACTIVE LIGAND

2005 ◽  
Vol 04 (01) ◽  
pp. 333-344 ◽  
Author(s):  
HIROTOSHI MORI ◽  
EISAKU MIYOSHI
Keyword(s):  
Density Functional ◽  
Molecular Level ◽  
Molecular Switch ◽  
Vibration Band ◽  
Functional Theory ◽  
Inorganic Molecule ◽  
Redox Active Ligand ◽  
Active Ligand ◽  
Redox Active ◽  
Stretching Vibration

A new inorganic molecule [ Co(Hbim) ( C 6 H 4 O 2)( NH 3)2]2 that can be used as a new optically durable molecular switch was theoretically designed in the framework of density functional theory. Three stable minima, belonging to 1 A g , 5 A 1, and 9 A g states, were found in the complex. Theoretically predicted infrared spectra of the complexes showed that a strong peak of NH stretching vibration is observed at 2690, 2120, and 2770 cm -1 in the 1 A g , 5 A 1, and 9 A g states, respectively. The apparent red shift of the NH stretching vibration band in the 5 A 1 state make it possible to distinguish the electronic state from others (1 A g and 9 A g ). This means that the complex can be used as a molecular level switch whose memory can be stably read by IR light without any photoreaction process; namely, without memory degradation.

First-Principles Study of Triangle Terarylene as a Possible Optical Molecular Switch

2011 ◽  
Vol 311-313 ◽  
pp. 526-529
Author(s):  
Cai Juan Xia ◽  
Han Chen Liu ◽  
Ji Xin Yin
Keyword(s):  
First Principles ◽  
Density Functional ◽  
Molecular Switch ◽  
Optical Switches ◽  
Functional Theory ◽  
Closed Ring ◽  
Potential Applications ◽  
Homo Lumo ◽  
Non Equilibrium Green’S Function ◽  
Theoretical Results

Using non-equilibrium Green’s function formalism combined with first-principles density functional theory, we investigate the electronic transport properties of a triangle terarylene(open- and closed-ring forms) optical molecular switch. The influence of the HOMO-LUMO gaps and the spatial distributions of molecular orbitals on the quantum transport through the molecular device is discussed. Theoretical results show that the conductance of the closed-ring is 3-8 times larger than that of open-ring, which expect that this system can be one of good candidates for optical switches due to this unique advantage, and may have some potential applications in future molecular circuit.

Structure, stability and intramolecular interaction of M(N5)2(M = Mg, Ca, Sr and Ba) : a theoretical study

RSC Advances ◽  
2015 ◽  
Vol 5 (28) ◽  
pp. 21823-21830 ◽  
Author(s):  
Xueli Zhang ◽  
Junqing Yang ◽  
Ming Lu ◽  
Xuedong Gong
Keyword(s):  
Energetic Materials ◽  
Density Functional ◽  
Alkaline Earth ◽  
Theoretical Study ◽  
Intramolecular Interaction ◽  
Earth Metal ◽  
Structure Stability ◽  
Alkaline Earth Metal ◽  
Functional Theory ◽  
The Density Functional Theory

The potential energetic materials, alkaline earth metal complexes of the pentazole anion (M(N5)2, M = Mg2+, Ca2+, Sr2+and Ba2+), were studied using the density functional theory.

Sign in / Sign up

Export Citation Format

Share Document