Evolution of the intensity of the 1458 cm^-1 and 768 cm^-1 bands of indene under VUV (120–180 nm) photolysis. Left column: evolution of the band intensities normalized to the initial value (I/I₀) as a function of time. Right column: logarithmic representation of the same decays shown in the left panels but versus fluence (estimated with assuming ), and fits (straight lines) of the linear decay interval to Eq. (2).