Structural Study of Boron - Nitride Nanotube with Magnetic Resonance (NMR) Parameters Calculation via Density Functional Theory Method (DFT)

Abstract

Abstract — A model of (4, 4) single-walled boron-nitride nanotube as a representative of armchair boron-nitride nanotubes studied. At first the structure optimization performed and then Nuclear Magnetic Resonance parameters (NMR) by Density Functional Theory (DFT) method at 11 B and 15 N nuclei calculated. Resulted parameters evaluation presents electrostatic environment heterogeneity along the nanotube and especially at the ends but the nuclei in a layer feel the same electrostatic environment. All of calculations carried out using Gaussian 98 Software package. Keywords — Boron-nitride nanotube, Density Functional Theory, Nuclear Magnetic Resonance (NMR). I. I NTRODUCTION INCE the discovery of carbon nanotubes (CNTs)[1], considerable attention has been attracted for synthesizing them due to their unique properties[2] and potential applications[3]-[5]. People have so far synthesized various structural and morphological CNTs such as multi-, single-, and double- walled[6],[7], as well as Y-, bamboo-, and cone-shaped CNTs[8],[9]. Recently boron nitride nanotubes (BNNT) in which BN unit is isoelectronic to C-C unit in CNT, have attracted increasing attention. The stability of BNNT was predicted firstly on the basis of semi-experiential tight binding (TB)[10] and local density approximated (LDA) density functional theory[11] calculations in 1994, and their synthesis was realized in 1995 with arc-charging method using the BN electrode packed into a metal casing[12] . Other preparation methods have been developed subsequently, such as arc-melting[13], high temperature chemical reaction[14], carbon nanotube templates[15], and laser ablating[16]. At same time, further theoretical investigations for the structures and electronic properties of BNNT have been reported [17]–[27]. Nuclear Magnetic Resonance (NMR) is a powerful tool for