Used to provide general guidelines for the design of carbon-nanotube-based biosensors, as well as to help explaining previously published experimental results. In addition, the adsorption near metallic electrodes is shown to have a negligible effect on the conductance of the tube due to the metal-induced gap states injected from the metal electrodes into the tube. The effects of the length of the tube and adsorption-site position on the conductance of the tube are discussed. Dear preet, Charge transfer on an atomNo of valence electrons on the atom-Density matrix value for that atom given in your M.P report For complete assistance refer to Dr. Short semi-metallic tubes are revealed to be sensitive to charged amino acids, and it is demonstrated that the conductance changes induced by the adsorption of the analyte in such tubes in a two-terminalĬonfiguration are bias-dependent. CC Computational Chemistry 2332-5968 Scientific Research Publishing 10.4236/cc.2016.41003 CC-63266 Articles Chemistry&Materials Science Density Functional Theory Study of Exohedral Carbon Atoms Effect on Electrophilicity of Nicotine: Comparative Analysis. To simulate the gas sensing system and analyze its electronic and transport properties, the structure is converted to a two-point probe sensor, as shown in Figure 1 2) and 4.92 Å. Various amino acids, while small-radius nanotubes are shown to be inadequate for sensing in aqueous media, as their response to the motion of the atoms resulting from the immersion in water is comparable to that of analyteĪdsorption. Mulliken population analysis is engaged to study the charge transfer between the graphene and ZnO and between the gas molecules and the ZnOgraphene system. r-s) could be divided according to atomic indexes A, B, Then number of blocks in. Fully metallic armchair tubes are found to be insensitive to Mulliken characteristics The sum of all the net and overlap populations equals the total number of electrons in the molecule: oss atomic (A) population : Gr Mulliken charge of atom A : Z.
It is found that geometrical deformationsĭo not play a major role in the sensing process, and that electrostatic interactions represent the major interaction mechanism between the tubes and amino acids. The mechanisms of interaction between carbon nanotubes and amino acids are elucidated. It is then shown that the major forces responsible for amino-acid adsorption on carbon nanotubes are van der Waals forces, and that hydrophobic interactions may accelerate the adsorption process, but are not necessaryįor it to occur. It is demonstrated how the improper choice of these parameters (particularly the basis set used in ab initio simulations) can lead to quantitatively and qualitatively erroneous conclusions regarding the bandgap of the nanotubes. Firstly, rules for the proper choice of the parameters used in these simulations are established.
In this thesis, molecular dynamics and ab initio density functional theory/nonequilibrium Green’s function simulations are used to study the interaction between carbon nanotubes and amino acids.
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