Vacuum Ultraviolet Photodissociation Dynamics of N _\textbf2 O+ \mathit\boldsymbolh\nu \rightarrow N _\textbf2 ( X^\textbf1 \mathit\boldsymbol\Sigma_ \rm\textbfg^\textbf+ )+O( ^\textbf1 S _\textbf0 ) in the Short Wavelength Tail of \mathit\boldsymbolD^\textbf1 \mathit\boldsymbol\Sigma^+ Band

Vacuum ultraviolet photodissociation dynamics of N _2 O+ h\nu \rightarrow N _2 ( X^1 \Sigma_ \rmg^+ )+O( ^1 S _0 ) in the short wavelength tail of D ^1 \Sigma^+ band has been investigated using the time-sliced velocity-mapped ion imaging technique by probing the images of the O( ^1 S _0 ) photoproducts at a set of photolysis wavelengths including 121.47 nm, 122.17 nm, 123.25 nm and 123.95 nm. The product total kinetic energy release distributions, vibrational state distributions of the N _2 ( X ^1 \Sigma_ \rmg^+ ) photofragments and angular anisotropy parameters have been obtained by analyzing the raw O( ^1 S _0 ) images. It is noted that additional vibrationally excited photoproducts (3 \leq v \leq 8) with a Boltzmann-like feature start to appear except the non-statistical component as the photolysis wavelength decreases to 123.25 nm, and the corresponding populations become more pronounced with decreasing of the photolysis wavelength. Furthermore, the vibrational state specific anisotropy parameter \beta at each photolysis wavelength exhibits a drastic fluctuation near \beta =1.75 at v < 8, and decreases to a minimum as the vibrational quantum number further increases. While the overall anisotropy parameter \beta for the N _2 ( X ^1 \Sigma_ \rmg^+ )+O( ^1 S _0 ) channel presents a roughly monotonical increase from 1.63 at 121.47 nm to 1.95 at 123.95 nm. The experimental observations suggest that there is at least one fast nonadiabatic pathway from initially prepared D^1 \Sigma^+ state to the dissociative state with bent geometry dominating to generate the additional vibrational structures at high photoexcitation energies.