نتایج جستجو برای: lopressor fullerenes

تعداد نتایج: 3611  

Journal: :Monthly Notices of the Royal Astronomical Society 2022

ABSTRACT Polycyclic aromatic hydrocarbons (PAHs) and fullerenes play a major role in the physics chemistry of interstellar medium (ISM). Based on number recent experimental theoretical investigations we developed model which PAHs are subject to photo-dissociation (carbon hydrogen loss) hydrogenation. We take into account that dehydrogenated may fold closed structures – fullerenes. Fullerenes, t...

2017
Sebastian Schimmel Zhixiang Sun Danny Baumann Denis Krylov Nataliya Samoylova Alexey Popov Bernd Büchner Christian Hess

We performed a study on the fundamental adsorption characteristics of Er3N@C80 deposited on W(110) and Au(111) via room temperature scanning tunneling microscopy and spectroscopy. Adsorbed on W(110), a comparatively strong bond to the endohedral fullerenes inhibited the formation of ordered monolayer islands. In contrast, the Au(111)-surface provides a sufficiently high mobility for the molecul...

1999
P. R. C. Kent M. D. Towler G. Rajagopal

The thermodynamic stability of structural isomers of C24, C26, C28 and C32, including fullerenes, is studied using density functional and quantum Monte Carlo methods. The energetic ordering of the different isomers depends sensitively on the treatment of electron correlation. Fixed-node diffusion quantum Monte Carlo calculations predict that a C24 isomer is the smallest stable graphitic fragmen...

Journal: :The Journal of organic chemistry 2003
Tamar Sternfeld Carlo Thilgen Zhongfang Chen Siefke Siefken Paul von Ragué Schleyer Walter Thiel François Diederich Mordecai Rabinovitz

A combined experimental and theoretical study was conducted on numerous higher fullerene anions with different sizes and shapes, C76-D2, C78-C2v, C78-D3, C84-D2, and C84-D2d. The corresponding fullerenes were reduced by lithium metal to diamagnetic multiply charged anions. The centers of gravity of the 13C NMR spectra of all the multiply charged anions were deshielded, relative to those of the ...

2013
Zhiguo Zhou

Fullerene medicine is a new but rapidly growing research subject. Fullerene has a number of desired structural, physical and chemical properties to be adapted for biological use including antioxidants, anti-aging, anti-inflammation, photodynamic therapy, drug delivery, and magnetic resonance imaging contrast agents. Chemical functionalization of fullerenes has led to several interesting compoun...

2011
Daniel Resasco

The unique properties of single-walled carbon nanotubes are a direct result of their distinctive structure, which is composed of C-C bonds more closely related to those in graphite than to those in diamond. That is, while diamond has a coordination number of four with sp hybridization, graphite involves three-coordinated carbons, in which three electrons are in sp hybridization and one is deloc...

2005
Thomas W. Ebbesen

C is an extraordinary element, considering the diversity of materials it forms. Ranging from sparkling gems to sooty filth, these materials have been studied and used for centuries, and carbon science was long thought to be a mature field. So when a whole new class of carbon materials— the fullerenes, such as C6o— appeared in the last decade, many scientists were surprised. The consequences hav...

Journal: :Physical review letters 2003
San-Huang Ke Harold U Baranger Weitao Yang

Using density-functional theory calculations, we investigate the addition energy (AE) of quantum dots formed of fullerenes or closed single-wall carbon nanotubes. We focus on the connection between symmetry and oscillations in the AE spectrum. In the highly symmetric fullerenes the oscillation period is large because of the large level degeneracy and Hund's rule. For long nanotubes, the AE osci...

Journal: :Computer Physics Communications 2004
Heng Liang Fengshan Bai

A partially structure-preserving method for sparse symmetric matrices is proposed. Computational results on the permanents of adjacency matrices arising from molecular chemistry are presented. The largest adjacency matrix of fullerenes computed before is that of C60 with a cost of several hours on supercomputers, while only about 6 min on an Intel Pentium PC (1.8 GHz) with our method. Further n...

2013
Christopher Arntsen Randa Reslan Samuel Hernandez Yi Gao Daniel Neuhauser

A method is introduced for simple calculation of charge transfer between very large solvated organic dimers (fullerenes here) from isolated dimer calculations. The individual monomers in noncentrosymmetric dimers experience different chemical environments, so that the dimers do not necessarily represent bulk-like molecules. Therefore, we apply a delocalizing bias directly to the Fock matrix of ...

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