VUV Photodissociation Dynamics of Nitrous Oxide: The N(²D_J=3/2,5/2) and N(²P_J=1/2,3/2) Product Channels

Abstract

We report on an experimental study of the vacuum ultraviolet photodissociation dynamics of nitrous oxide as a function of photolysis wavelength. In this study, both the N((2)DJ) + NO(X(2)Π) and N((2)PJ) + NO(X(2)Π) product channels were investigated using the time-sliced velocity ion imaging technique. Images of the N((2)DJ=5/2,3/2) and N((2)PJ=3/2,1/2) products were measured at seven and ten, respectively, photolysis wavelengths between 124.44 and 133.20 nm. The vibrational states of the NO products were partially resolved in the acquired raw ion images. The total kinetic energy release and the branching ratios of different vibrational states of NO products were determined. The vibrational state distributions of NO were found to be inverted for the N((2)DJ=5/2,3/2) and N((2)PJ=3/2,1/2) product channels. This phenomenon indicates that the N-O bond is highly vibrational excited during the breaking of the N-N bond. Vibrational state resolved anisotropic parameters β in both the N((2)DJ) and the N((2)PJ) channels were acquired. The small β values (around 0.5) in the dissociation process suggest that transition states in a bent configuration play an important role in the formation of N + NO products.

Observation of the Carbon Elimination Channel in Vacuum Ultraviolet Photodissociation of OCS

“…Here we report a synergistic experimental and theoretical study on VUV photodissociation of OCS→ SO­( 3 Σ – ) + C­( 3 P). The experiments were carried out using a time-sliced velocity map ion imaging (VMI) setup with very high energy and angular resolutions, which has been described previously − and in the Supporting Information. By detecting the ion images of C­( 3 P J =0 ) products, the SO + C channel was clearly observed.…”

Photodissociation Dynamics of OCS near 150 nm: The S(1SJ=0) and S(3PJ=2,1,0) Product Channels

“…The experiment was performed using a molecular beam apparatus combined with a time-sliced ion imaging detector. − This apparatus has been depicted elsewhere. − To put it simply, a pulsed supersonic molecular beam of OCS (5% OCS + 95% Ar) was produced using a pulsed valve (General valve, Parker series 9). The pulsed valve was mounted vertically upward in a source chamber and worked at a repetition rate of 20 Hz.…”

Quantum state-to-state vacuum ultraviolet photodissociation dynamics of small molecules

“…Their setup was equipped with a Kr gas cell which can generate two tunable VUV laser beams by TPR-FWM. They have used this setup to study the photodissociation dynamics of N 2 O in the two VUV wavelength ranges of 124.44−133.20 nm [79,80] and 142.55−148.79 nm [81,82]. In both of the wavelength ranges, the photo-products O( 3 P 0,1,2 ), O( 1 S), N( 2 D 3/2,5/2 ) and N( 2 P 1/2,3/2 ) were selectively detected by the VMI setup, and the angular distributions and quantum vibrational populations of N 2 or NO for the dissociation channels O…”

“…On the other hand, the channels for producing N( 2 D 3/2,5/2 ) and N( 2 P 1/2,3/2 ) have β parameters close to 0.5, and the vibrational populations of the co-product NO are strongly inverted. This suggests that a bent transition state should be present in the formation of N+NO [80]. In the range 142.55−148.79 nm, N 2 O is believed to be excited to the C 1 Π state.…”