Figure 11.

Nanocavitation by 157 nm laser photodissociation of polyacrylamide (PAM) matrixes: (a) Molecular photodissociation at 157 nm. Vertical arrows indicate photon transitions between two vibrational levels of the ground (A) and an excited electronic state (Β). A transition from the excited to a repulsive electronic state (red curve) through an avoided crossing via a vibration state at the point (Γ) is very fast (< 1 ps) and breaks a molecular bond in the polymeric chain; (b) PAM surface irradiation with 157 nm photons; (c) (DE): a bond break is followed by molecular decomposition and nanocavitation; (d) (CL): possible recombination of carbon dissociative products, and cluster formation in the gas phase; (e) carbon cluster deposition on the polymeric matrix and possible structure of carbon nanocavitation.