Addition Reaction between Piperidine and C60 to Form 1,4-Disubstituted C60 Proceeds through van der Waals and Dative Bond Complexes: Theoretical and Experimental Study

Author(s):  
Rabindranath Lo ◽  
Debashree Manna ◽  
Maximilián Lamanec ◽  
Weizhou Wang ◽  
Aristides Bakandritsos ◽  
...  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Long Zhang ◽  
Zhe Zhang ◽  
Fengcheng Wu ◽  
Danqing Wang ◽  
Rahul Gogna ◽  
...  

AbstractMoiré lattices formed in twisted van der Waals bilayers provide a unique, tunable platform to realize coupled electron or exciton lattices unavailable before. While twist angle between the bilayer has been shown to be a critical parameter in engineering the moiré potential and enabling novel phenomena in electronic moiré systems, a systematic experimental study as a function of twist angle is still missing. Here we show that not only are moiré excitons robust in bilayers of even large twist angles, but also properties of the moiré excitons are dependant on, and controllable by, the moiré reciprocal lattice period via twist-angle tuning. From the twist-angle dependence, we furthermore obtain the effective mass of the interlayer excitons and the electron inter-layer tunneling strength, which are difficult to measure experimentally otherwise. These findings pave the way for understanding and engineering rich moiré-lattice induced phenomena in angle-twisted semiconductor van der Waals heterostructures.


1990 ◽  
Vol 86 (13) ◽  
pp. 2473 ◽  
Author(s):  
Hellmut Haberland ◽  
Hans Kornmeier ◽  
Helge Langosch ◽  
Michael Oschwald ◽  
Gregor Tanner

2017 ◽  
Vol 1 (6) ◽  
Author(s):  
Weiyu Xie ◽  
Toh-Ming Lu ◽  
Gwo-Ching Wang ◽  
Ishwara Bhat ◽  
Shengbai Zhang

.This paper describes an experimental study of the van der Waals dispersion forces between curved mica surfaces. For separations in the range 1.4 to 20 nm the forces were determined by the jump method described in earlier work by Tabor & Winterton (1969). For larger separations the forces were determined by a new dynamic method. One surface was supported on a rigid piezo-electric crystal and could be set vibrating at very small amplitudes over a convenient range of frequencies. The other was supported, facing it, on a stiff spring: its natural frequency depended both on the spring stiffness and on the van der Waals force exerted upon its by the first surface. By determining the resonant frequency as a function of separation the law of force was deduced in the range 10 to 130 nm. Both methods thus covered the range from 1.4 to 130 nm. In this way it is shown that there is a gradual transition between non-retarded and retarded forces as the separation is increased from 12 to 50nm. Experiments have also been carried out on the influence of adsorbed fatty acid monolayers on the van der Waals interaction between mica surfaces. The results show that for separations greater than about 5 nm the forces are as for bulk mica: for separations less than 3 nm the forces are slightly less and appear to be dominated by the van der Waals properties of the monolayers themselves.


2020 ◽  
Vol 41 (4) ◽  
pp. 645-648 ◽  
Author(s):  
Sadegh Kamaei ◽  
Ali Saeidi ◽  
Farzan Jazaeri ◽  
Amin Rassekh ◽  
Nicolo Oliva ◽  
...  

Author(s):  
S T Chinenov ◽  
A E Zarvin ◽  
V E Khudozhitkov ◽  
V V Kalyada ◽  
A S Yaskin

2003 ◽  
Vol 10 (02n03) ◽  
pp. 289-293 ◽  
Author(s):  
Andriy Dmytruk ◽  
Volodymyr Ovechko

An oscillators model of physical adsorption on a silica surface has been built considering the molecular adsorbent-adsorbate complex as two relatively individual parts united by a weak van der Waals interaction. An experimental study of the NIR spectra of ammonia and p-xylene molecules adsorbed in a porous glass has been carried out. Theory and experiment agree well.


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