Simulations of nanosensors based on single walled carbon nanotubes

Accurate modeling approach for the structural comparison between monolayer polymer tubes and single-walled nanotubes

“…In this paper we argued that polyhedral models for nanotubes are useful for the description of respective structures in computational studies. The corrections introduced by those models compared to the commonly used pictures are in general not negligible (see also a recent study on the effect of chirality on nanotube vibrations [18]). In particular, the polyhedral model for boron nanotubes reflects the findings of monolayer polymer nanotube structures found earlier.…”

Visualization of electronic density

“…The essential parameter for model analysis is the width of the nanotube wall, and it is the electronic cloud around the atomic nuclei that determines this. In a series of papers and a thesis, Pine and coworkers [23][24][25][26][27][28][29] reviewed the literature and carried out extensive classical molecular dynamics simulations at the atomistic scale to carefully determine the limits of applicability of the analytic theory. While values for the wall width were deduced indirectly by us and many others, direct estimation is of course more desirable.…”

“…For a nanotube of radius r, length L, and volume V the frequency of the nth mode, f n , of its vibrations depend on the nanotube's width, w and radius r via two quantities used in its calculation: the moment of inertia, I = π rw(4r 2 + w 2 ) and mass linear density ρ L = 2π rwρ V (ρ L is the density per unit length and ρ V the density per unit volume) which are related to the tubes' Young's modulus, E. The exact relation depends on the boundary conditions and model; and the main point of [24][25][26][27][28] was to deduce these frequencies without explicit use of any of the competing analytic models. Literature estimates of E range between 1-6 Tpa, and this is known as Yakobson's paradox [30].…”

“…The nanotube simulations at the atomistic scale that form the basis for the present study are described in [24][25][26][27][28] with codes given in [29]. In brief the tube is equilibrated with periodic boundary conditions, then ''cut open'' and clamped with the appropriate boundary conditions.…”

“…For example, to the study of any system that involves proximity and contact between different materials such as adsorption of molecules on surfaces. One such case (but certainly not limited to) is the next stage of the nanotube vibration project [27]. Our motivation for the study of nanotube vibrations was to study the way that the adsorption of DNA onto a nanotube would change the vibrational frequencies, hence enabling evaluation of the DNA mass.…”