Nanotube optical transition
= Nanotube optical transition
{title2=$E_{ii}$}
An optical excitation between nanotube electronic subbands, often labelled $E_{ii}$ for prominent axial-polarization transitions. One-dimensional <Van Hove singularities> enhance the <joint density of states>, but <selection rules>, <oscillator strengths> and strong <excitons> interactions determine actual absorption peaks. <Dielectric> environment, bundling, doping and defects can change those peaks.