TDDFT approach on laser field enhancement by carbon nanotube and photo-decomposition of water

In this presentation, we discuss field enhancement of femtosecond laser by carbon nanotubes and application to accelerating water photo-decomposition. The real-time time-dependent density functional theory (TDDFT) was employed for simulating water photo-decomposition near (8,0) semiconducting carbon nanotube. A short pulse with full-width of half-maximum 10fs was considered. When optical field is perpendicular to the tube axis, we found significant laser field enhancement corresponding to laser-power enhancement by factor 2 with laser wavelength 800 nm, and by factor around 8 with wavelength 400 nm. The enhancement is due to polarizability and wall-curvature of carbon nanotube that helps to reduce threshold power for photo-decomposition of water.