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1.
Mohammad T. Baei 《Monatshefte für Chemie / Chemical Monthly》2012,18(3):881-889
Abstract
Density functional theory (DFT) calculations were performed to investigate the electronic structure properties of Ge-doped boron phosphide nanotubes (BPNTs) as a semiconductor at the B3LYP/6-31G* level of theory in order to evaluate the influence of Ge doping on (4,4) armchair BPNTs. We extended the DFT calculations to predict the electronic structure properties of Ge-doped boron phosphide nanotubes, which are very important for production of solid-state devices and other applications. The isotropic (CSI) and anisotropic (CSA) chemical shielding parameters for the sites of various 11B and 31P atoms, and the quadrupole coupling constant (C Q) and asymmetry parameter (η Q) at the sites of various 11B nuclei, were calculated in pristine and Ge-doped (4,4) armchair BPNT models. The calculations indicated that, in these two forms of Ge-doped BPNTs, the binding energies are not attractive and do not characterize a chemisorption process. In comparison with the pristine model, the band gap of the two forms of Ge-doped BPNTs is reduced and increases their electrical conductance. The dipole moments of the Ge-doped BPNT structures show notable changes with respect to the pristine model. The nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) results show that the GeB model is a more reactive material than the pristine or GeP model. 相似文献2.
Biplab Goswami Chanchal Ghosh Sougata Pal Pranab Sarkar 《International journal of quantum chemistry》2006,106(4):887-893
We present theoretical results of size dependent structural, electronic, and optical properties of ligand‐free stoichiometric AlnAsn clusters of zinc‐blende modification. The investigation is done using a simplified parametrized linear combination of atomic orbital–density functional theory‐local density approximation–tight‐binding (LCAO–DFT–LDA–TB) method and consider clusters with n up to around 100. Initial structures have assumed as spherical parts of infinite zinc‐blende structure and then allowed to relax to the closest local‐energy‐minimum structure. We analyze the radial distributions of atoms, Mulliken populations, electronic energy levels (in particular, HOMO and LUMO), bandgap, and stability as a function of size and composition. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 相似文献
3.
Zusammenfassung Zwei neue binäre Vanadinarsenide werden identifiziert: V5As3 mit W5Si3-Struktur (T1) und V1,5As, dessen Elementarzelle bestimmt wird. Im Dreistoff V–As–C werden zwei ternäre Phasen sichergestellt: V5As3C0,7 mit teilweise aufgefüllter Mn5Si3-Struktur und V2AsC mit Cr2AlC-Struktur (H-Phase).
Mit 1 Abbildung 相似文献
Two new binary vanadium arsenides have been identified: V5As3 with W5Si3-structure (T1) and V1,5As, of which the unit cell is determined. Two ternary phases were found in the ternary system V–As–C: V5As3C0·7 having partially filled Mn5Si3-structure; V2AsC cristallizes with the Cr2AlC-type (H-phase).
Mit 1 Abbildung 相似文献
4.
Prof. Dr. F. Höfler 《Monatshefte für Chemie / Chemical Monthly》1976,107(2):411-420
The vibrational spectra of C6D5SiX
3 (X=H, Cl, Br), (C6D5)2SiCl2, (C6D5)3SiCl, and Si
n
(C6D5)2n
(n=4, 5) are reported and assigned. The C6H5/C6D5 isotopic shifts in the lower frequency region (100–600 cm–1) are used to elucidate vibrational coupling effects, which occur between silicon-phenyl and silicon-halogen or silicon-silicon modes.
Herrn Prof. Dr.H. Grubitsch mit den besten Wünschen zum 70. Geburtstag gewidmet. 相似文献
Herrn Prof. Dr.H. Grubitsch mit den besten Wünschen zum 70. Geburtstag gewidmet. 相似文献
5.
Ulrich Wannagat Erich Bogusch Peter Geymayer Farroch Rabet 《Monatshefte für Chemie / Chemical Monthly》1971,102(6):1844-1850
Zusammenfassung Spezielle Umsetzungen von 1,3-Dichlordisilazanen werden beschrieben. Die Umsetzung mit einem bestimmten Amin führte zu einer SiNSiN-Verbindung mit 6 verschiedenen Substituenten (I; Rk. 1). Analog bildeten sich mit Hydrazinen Bis(hydrazino)-disilazane der Strukturgruppe NNSiNSiNN (II, III; Rk. 2). Mit Äthylendiamin konnte ein Si2N3C2-Siebenringsystem (IV), mit Bis(trimethylsilyl)harnstoff ein Sechsringsystem Si2N3C (VI), mit Diphenylsilandiol das Cyclotrisildioxazan-Sechsringsystem (VIII, IX) aufgebaut werden. 1,3-Dichlordisiloxan ergab in ähnlichen Umsetzungen erstmalig ein Si2N2OC2-Siebenringsystem (V) und ein Si2N2OC-Sechsringsystem (VII).
97. Mitt.:U. Wannagat, L. Gerschler undH. J. Wismar, Mh. Chem.102, 1834 (1971).
Vorläufige Mitt. von Teilergebnissen:U. Wannagat, Angew. Chem.77, 626 (1965); Pure appl. Chem.13, 262 (1966).
Mit Auszügen aus den DissertationenE. Bogusch, Techn. Hochschule Graz 1966, undF. Rabet, Techn. Univ. Braunschweig 1971, sowie nach Arbeiten vonP. Geymayer, Techn. Hochschule Graz 1965. 相似文献
New reactions of 1.3-dichlorodisilazanes and 1.3-dichlorodisiloxanes. (chemistry of silicon-nitrogen compounds, XCVIII)
Special reactions of 1.3-dichlorodisilazanes give a) with a special amine a SiNSiN-compound with 6 different substituents (I; equ. 1); b) with hydrazines bis(hydrazino)disilazanes of the structural unit NNSiNSiNN (II, III; equ. 2); c) with ethylenediamine a novel Si2N3C2-sevenmembered ring system (IV); d) with bis(trimethylsilyl)urea a sevenmembered ring system Si2N3C (VI); e) with diphenylsilanediol the cyclotrisildioxazane ring system (VIII, IX). Analogous reactions of 1.3-dichlorodisiloxanes lead to the novel sevenmembered ring system Si2N2OC2 (V) and to the sixmembered Si2N2OC-ring system (VII).
97. Mitt.:U. Wannagat, L. Gerschler undH. J. Wismar, Mh. Chem.102, 1834 (1971).
Vorläufige Mitt. von Teilergebnissen:U. Wannagat, Angew. Chem.77, 626 (1965); Pure appl. Chem.13, 262 (1966).
Mit Auszügen aus den DissertationenE. Bogusch, Techn. Hochschule Graz 1966, undF. Rabet, Techn. Univ. Braunschweig 1971, sowie nach Arbeiten vonP. Geymayer, Techn. Hochschule Graz 1965. 相似文献
6.
《Physics and Chemistry of Liquids》2012,50(3):301-313
Abstract This paper reports experimental results concerning the isobaric heat capacity Cp of Liquid n-pentadecane as a function of pressure (up to 100 MPa) and temperature (313.15 to 373.15 K). The measurements were performed with a modified C80 SETARAM calorimeter based on the Calvet principle. These calorimetric data, combined with density data, were used to evaluate derived thermophysical properties such as the isochoric heat capacity Cv , the isentropic compressibility ks and the speed of sound u in the same ranges of pressure and temperature. The pressure-temperature behaviour of these properties was then discussed as a model for simple organic liquids. 相似文献
7.
Siti Syaida Sirat Hafiz Malik Hussien Abdelnasir Omar bin Shawkataly 《Phosphorus, sulfur, and silicon and the related elements》2020,195(5):429-436
AbstractThe solid-state structures of compounds PPh2CH2SPh (1) and PPh2C6H4SMe (2) were determined by single crystal X-ray diffraction. Experimental results on the molecular structures of compounds 1 and 2 were supported by Hirshfeld surface analysis and Density Functional Theory (DFT). The computed values calculated at DFT level using B3LYP function with 6-311++G (3df, 3pd) (P, S) and 6-31G* (C, H) basis sets are in good agreement with the experimental results. 相似文献
8.
Dr. Vu Thi Ngan Prof. Ewald Janssens Dr. Pieterjan Claes Prof. Jonathan T. Lyon Dr. André Fielicke Prof. Dr. Minh Tho Nguyen Prof. Dr. Peter Lievens 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(49):15788-15793
We report on the structural, electronic, and magnetic properties of manganese‐doped silicon clusters cations, SinMn+ with n=6–10, 12–14, and 16, using mass spectrometry and infrared spectroscopy in combination with density functional theory computations. This combined experimental and theoretical study allows several structures to be identified. All the exohedral SinMn+ (n=6–10) clusters are found to be substitutive derivatives of the bare Sin+1+ cations, while the endohedral SinMn+ (n=12–14 and 16) clusters adopt fullerene‐like structures. The hybrid B3P86 functional is shown to be appropriate in predicting the ground electronic states of the clusters and in reproducing their infrared spectra. The clusters turn out to have high magnetic moments localized on Mn. In particular the Mn atoms in the exohedral SinMn+ (n=6–10) clusters have local magnetic moments of 4 μB or 6 μB and can be considered as magnetic copies of the silicon atoms. Opposed to other 3d transition‐metal dopants, the local magnetic moment of the Mn atom is not completely quenched when encapsulated in a silicon cage. 相似文献
9.
10.
Chang‐Jiang Yao Dr. Ren‐Hui Zheng Hai‐Jing Nie Bin‐Bin Cui Prof. Dr. Qiang Shi Prof. Dr. Jiannian Yao Prof. Dr. Yu‐Wu Zhong 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(37):12376-12387
Two series of linear ruthenium coordination oligomers, [(Ntpy)Run(tppz)n?1(tpy)]2n+ (mono‐Ntpy series, n=1–3) and [(Ntpy)2Run(tppz)n?1]2n+ (bis‐Ntpy series, n=1–3) have been prepared, where Ntpy is the capping ligand 4′‐di‐p‐anisylamino‐2,2′:6′,2′′‐terpyridine, tppz is tetra‐2‐pyridylpyrazine, and tpy is 2,2′:6′,2′′‐terpyridine. The electrochemical measurements evidence oxidation events from both the amine segments and the metal centers and reduction waves from tppz and the capping ligands. Both series complexes display much enhanced light absorption with respect to model complexes without terminal amine units. Density functional theory (DFT) calculations have been performed on both series and time‐dependent DFT (TD‐DFT) calculations have been performed on the bis‐Ntpy‐series compounds (n=1–4) to characterize their electronic structures and excited states and predict the electronic properties of long‐chain polymers. Upon one‐electron oxidation, the mono‐Ntpy‐series monoruthenium and diruthenium complexes display N+‐localized transitions and metal‐to‐nitrogen charge‐transfer (MNCT) transitions in the near‐infrared (NIR) region. DFT and TD‐DFT computations on the one‐electron‐oxidized forms of the mono‐Ntpy‐series compounds (n=1–4) provide insight into the nature of the MNCT transitions and the degree of charge delocalization. 相似文献
11.
《Journal of computational chemistry》2017,38(18):1574-1582
In this work, we designed a series of superalkali‐doped Si12C12 nanocage M3O@Si12C12 (M = Li, Na, K) with donor–acceptor framework. Density functional theory calculations demonstrated that the HOMO–LUMO gap of the complexes conspicuously narrowed with increase of atomic number of the alkali metal, the value decreased from 5.452 eV of pure Si12C12 nanocage to 3.750, 2.984, and 2.634 eV of Li3O@Si12C12, Na3O@Si12C12, and K3O@Si12C12, respectively. This finding shows that the pristine Si12C12 cluster could be transformed to n‐type semiconductor by introduction of the superalkali M3O. We also showed that the superalkali doping remarkably enhanced the first hyperpolarizability of Si12C12. Among the studied systems, K3O@Si12C12 not only has the narrowest gap but also has the strongest nonlinear optical (NLO) properties, its first hyperpolarizability reached as high as 21695 a.u. The striking results presented in this work will be beneficial for potential applications of the Si12C12‐based nanostructure in the electronic nanodevices and high‐performance NLO materials. © 2017 Wiley Periodicals, Inc. 相似文献
12.
Maofa Ge Jikang Feng Cheng Yang Zhiru Li Chiachung Sun 《International journal of quantum chemistry》1999,71(4):313-318
The geometric configurations and electronic structures of the TinC2n (n=1–6) clusters were studied by using the quantum chemical ab initio density functional theory (DFT) method. Our studies showed that these TinC2n (n=1–6) could grow gradually to form cyclic clusters through the subunits TiC2 bonding to each other by C C or Ti C bond. The result could explain the existing experimental fact. The studies might also be helpful to the knowledge of the formation mechanism of the Met‐Cars. ©1999 John Wiley & Sons, Inc. Int J Quant Chem 71: 313–318, 1999 相似文献
13.
Aimei Gao Guoliang Li David Finlow Hongyu Chen Qian‐Shu Li 《International journal of quantum chemistry》2012,112(5):1499-1506
The effect of the composition ratio between arsenic and silicon atoms on the structures and properties of AsxSi6?x (x = 0–6) have been systematically investigated using the density functional theory at the B3LYP/6‐311+G* level. The AsxSi6?x clusters prefer substitutional rather than attaching structures; the Si‐rich clusters favor Si6‐like structures, whereas the As‐rich clusters prefer As6‐like structures. The As atoms locating at the framework may explain the difficulty of removal of arsenic impurities from polycrystalline silicon. In general, the average binding energies gradually decrease, implying the AsxSi6?x clusters become increasingly unstable as x increases. Both the HOMO‐LUMO gaps and the As‐dissociation energies present a strong even–odd alternation, implying alternating chemical stability, with the even x members being more stable than the odd ones. The dissociation energies of an As atom from AsxSi6?x are: 3.07, 2.84, 1.84, 2.52, 1.86, and 2.85 eV, for x = 1–6, respectively, and 3.80, 3.08, 2.64, 3.01, 2.93, 3.16 eV for Si (x = 0–5). These dissociation energy results should provide a useful reference for further experimental investigations. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 相似文献
14.
A. Yu. Shaulov 《Polymer Science Series B》2006,48(6):308-323
Monoelemental polymers with various chemical constitutions and different spatial structures (linear Te n , Se n , and S n ; planar graphite C n , black phosphorus P n , As n , Sb n , and Bi n ; and chemically bonded three-dimensional diamond C n , B n , Si n , and Ge n ) were considered and categorized as a class of covalent macromolecular compounds. Quantitative expressions relating the thermal (melting point, thermal expansion coefficient, heat conductivity) and elastic (microhardness, bulk compression modulus of elasticity) properties of polymers to the energy of intra-and intermolecular interactions and the equilibrium length of chemical bonds in the crystalline and glassy states are given. A numerical correlation between the spatial structure of polymers and their thermal and elastic properties was obtained. The hypothetical melting point of diamond at normal pressure was calculated as T f = 3155 K. 相似文献
15.
Dr. Christoph Schwarzmaier Dr. Michael Bodensteiner Dr. Alexey Y. Timoshkin Prof. Dr. Manfred Scheer 《Angewandte Chemie (International ed. in English)》2014,53(1):290-293
The reaction of a P4 butterfly complex with yellow arsenic yields the largest mixed PnAsm ligand complexes synthesized to date. [{Cp′′′Fe(CO)2}2(μ,η1:1‐P4)] reacts with As4 to yield [{Cp′′′Fe}2(μ,η4:4‐PnAs4‐n)] and [Cp′′′Fe(η5‐PnAs5‐n)]. Mass spectrometry together with NMR spectroscopy and X‐ray crystallography give clear evidence about the arrangement of the E positions within the cyclo‐E5 and E4 moieties of the products. Moreover, the results of DFT calculations agree well with the experimental determined outcomes. By coordinating the E4 complex [{Cp′′′Fe}2(μ,η4:4‐PnAs4‐n)] with CuCl, a rearrangement of the E positions occurs in favor with a preferred phosphorus coordination towards copper atoms in the resulting 1D polymeric chain. 相似文献
16.
V. I. Vovna I. S. Os’mushko V. V. Korochentsev N. P. Shapkin M. V. Tutov 《Journal of Structural Chemistry》2010,51(5):875-880
The electronic structure of polyvinylsiloxane polymeric chains (Si2O3(CHCH2)2)n is studied by X-ray photoelectron spectroscopy and quantum chemistry in the DFT approximation. The binding energy of C and
O ls electrons occupying inequivalent positions in the polymer coincides within the experimental accuracy. The binding energies
for C and O (284.9 eV and 532.4 eV) and for Si2p-electrons (102.7 eV) well agree with the values for related compounds. The experimental data for the binding energy are reproduced
in HF and DFT calculations only with the extended 6–311**(d) basis set. The highest occupied levels of the polymer are fy orbitals of vinyl groups 相似文献
17.
Martin F. Jarrold 《Journal of Cluster Science》1991,2(3):137-181
Recent studies of the chemistry of elemental clusters (such as C
n
, Si
n
, and Fe
n
) in the gas phase have revealed a number of fascinating results. This review article discusses and compares the various techniques that have been used to investigate the chemical properties of gas phase elemental clusters. Examples are provided of the often complimentary information that can be obtained from the different methods. 相似文献
18.
19.
《Physics and Chemistry of Liquids》2012,50(2):81-90
Abstract Calculation of CP from a model soft-core equation of state reveals a line in the phase diagram on which CP is equal to its zero pressure value C P 0 . This line commences on the temperature axis where the second virial coefficient has a point of inflexion. At higher temperatures (and pressures) CP falls below C P 0 . The detailed behaviour of CP is presented via contour maps, illustrating the effects of changing the exponent N(= 3/n, where n is the repulsive potential exponent) which parameterizes the model. For soft-core fluids at high temperatures CP deviates only slightly from the ideal gas value over a wide range of temperature and density, in marked contrast to the behaviour of hard-core models. 相似文献
20.
In this work, we present a theoretical study (based on DFT‐calculations) of the electronic properties of compounds crystallising in a NH4Pb2Br5 type structure in a wide pressure range. The main focus of this study is to elucidate the nature of bonding of the ns2‐cations at ambient and elevated pressure. For a better understanding of the structure and bonding, the DOS of these compounds are evaluated and discussed on the basis of a simple model assuming mainly ionic interactions. The calculations are complemented by an orbital analysis using the crystal orbital Hamilton population (COHP) and an analysis of the electronic density topology with the electron localisation function (ELF). Structural and theoretical investigations give results that are in excellent agreement: The DFT‐calculations confirm the existence of bonding interactions between the ns2‐cations at elevated pressure. Our study indicates that the “character” of the additional electron pair changes with increasing pressure from nonbonding to bonding in agreement with a simple model system of two interacting ns2‐cations. 相似文献