نتایج جستجو برای: lopressor fullerenes

تعداد نتایج: 3611  

Journal: :The Journal of chemical physics 2008
Murilo L Tiago P R C Kent Randolph Q Hood Fernando A Reboredo

We investigate the accuracy of first-principles many-body theories at the nanoscale by comparing the low-energy excitations of the carbon fullerenes C(20), C(24), C(50), C(60), C(70), and C(80) with experiment. Properties are calculated via the GW-Bethe-Salpeter equation and diffusion quantum Monte Carlo methods. We critically compare these theories and assess their accuracy against available p...

1998
Kikuo Harigaya

Nonlinear optical properties in the fullerene C60 and the extracted higher fullerenes – C70, C76, C78, and C84 – are theoretically investigated by using the exciton formalism and the sum-overstates method. We find that off-resonant third order susceptibilities of higher fullerenes are a few times larger than those of C60. The magnitude of nonlinearity increases as the optical gap decreases in h...

Journal: : 2022

The review examines experimental and theoretical works devoted to the description of modern methods for preparation iron endometal-fullerenes(EMF), as well that dispute such results due extremely low efficiency used methods. paper also considers advantages disadvantages synthesis, areas possible application synthesis products. It is shown EMF obtained mainly by two - arc discharge (plasma) usin...

2013
Daniel Shechtman

Three surprising discoveries on the nature of matter and its properties were published in the mid-1980s. All these discoveries led to Nobel prizes. The first discovery was in 1985, when fullerenes were discovered by Robert F. Curl Jr, Sir Harold W. Kroto, and Richard E. Smalley. Fullerenes, also known as buckyballs, are spherical molecules composed of carbon atoms. The discovery of fullerenes l...

Journal: :The journal of physical chemistry. A 2006
Cheng H Sun Gao Q Lu Hui M Cheng

How can the accuracy of the calculated standard heats of formation DeltaHf0 of fullerenes be improved? How reliable are the values of DeltaHf0 calculated from hyperhomodesmotic reactions? This work is the first to address these questions. By comparing the results obtained from three hyperhomodesmotic reactions containing only fullerenes, it is illustrated that both the resonance contribution an...

Journal: :The journal of physical chemistry. B 2005
Anil K Sadana Feng Liang Bruce Brinson Sivaram Arepalli Samir Farhat Robert H Hauge Richard E Smalley W E Billups

Large fullerenes and carbon-coated metal nanoparticles that are formed during the synthesis of carbon nanotubes have been functionalized by the addition of alkyl radicals and isolated by extraction into chloroform. The soluble, functionalized fullerenes have been isolated from raw single-wall carbon nanotube (SWNT) material prepared by laser oven, direct current arc, and high-pressure carbon mo...

Journal: :Eur. J. Comb. 2007
Jack E. Graver

We explore the relationship between Kekulé structures and maximum face independence sets in fullerenes: plane trivalent graphs with pentagonal and hexagonal faces. For the class of leap-frog fullerenes, we show that a maximum face independence set corresponds to a Kekulé structure with a maximum number of benzene rings and may be constructed by partitioning the pentagonal faces into pairs and 3...

2011
Nikolai A Poklonski Sergey A Vyrko Eugene F Kislyakov Nguyen Ngoc Hieu Oleg N Bubel' Andrei M Popov Yurii E Lozovik Andrey A Knizhnik Irina V Lebedeva Nguyen Ai Viet

The changes of dynamical behaviour of a single fullerene molecule inside an armchair carbon nanotube caused by the structural Peierls transition in the nanotube are considered. The structures of the smallest C20 and Fe@C20 fullerenes are computed using the spin-polarized density functional theory. Significant changes of the barriers for motion along the nanotube axis and rotation of these fulle...

Journal: :Physical review letters 2000
Shvartsburg Hudgins Dugourd Gutierrez Frauenheim Jarrold

The hypothesis that fullerenes grow in a carbon plasma by the addition of C2 units (the "fullerene road") has been widely acclaimed as the most plausible mechanism for formation of larger fullerenes including C60 and C70. Calculations suggest that the association of C2 with fullerenes proceeds through two classes of intermediates, "sticks" and "handles." Here we report the observation of these ...

Journal: :iranian journal of mathematical chemistry 2014
f. koorepazan-moftakhar kh. fathalikhani

in this paper, we calculate the eccentric connectivity index and the eccentricity sequence of two infinite classes of fullerenes with 50 + 10k and 60 + 12k (k in n) carbon atoms.

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