ABSTRACT

Carbon nanotubes (CNTs) have aroused much interest in scientists and technicians since their discovery in 1991, due to the unique physical properties that they exhibit. These properties could impact broad areas of science and technology, ranging from probe tips used for imaging to ultrasensitive gas sensors. This chapter reviews the optimized configurations of finite open single-walled carbon nanotubes (SWCNTs) based on the density functional theory (DFT). It helps to calculate the spectra of electronic absorption by the time-dependent density functional theory (TDDFT) and discusses their anisotropy. The chapter presents the dynamic third-order optical polarizabilities and TPA properties in terms of the sum-over-states (SOS) method combined with TDDFT and also help to understand the electronic origins of nonlinear optical (NLO) responses for this type of nanotubes. Silicon-carbon nanotubes (SiCNTs) are predicted to be more suitable materials for hydrogen storage than pure CNTs at a theoretical level.