The photodissociation dynamics of N2O in the wavelength region of 203-205 nm was studied by velocity map ion imaging. A speed resolution of 0.8% was obtained using standard projection imaging and subpixel centroiding calculations. To investigate N2O dissociation starting from the excited bending levels in the ground electronic state, a supersonic molecular beam and an effusive beam were used. The photoabsorption transition probability from the first excited bending level in the wavelength region of 203-205 nm was estimated to be seven times greater than that from the ground vibrational level.

Energy partitioning in the 203-205 nm photodissociation of N 2 O was studied by velocity map ion imaging of O( 1 D 2 ) and (2+1) resonance-enhanced multiphoton ionization (REMPI) of N 2 (X 1 ∑ g + ) via the a′′( 1 ∑ g + ) state. The observed translational energy distribution of O atoms exhibited a discrete structure due to quantized rotational energies of the counterpart N 2 fragments. The maximum of the N 2 rotational distribution has shifted from J ) 72 to 74 in changing the photodissociation wavelength from 205.5 to 203.8 nm. Comparison of the translational energy distribution of O( 1 D 2 ) with the REMPI spectrum of N 2 (X 1 ∑ g + ) revealed that the REMPI intensities of N 2 via particular rotational levels in the a′′ state were specifically reduced. These rotational levels exhibited energy shifts due to perturbation, indicating that the REMPI efficiency is reduced by the interactions between the a′′ state and other valence electronic state(s).

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Instantaneous chirality induced by zero-point vibrations was observed directly by using the Coulomb explosion imaging (CEI) technique. The present results suggest the CEI would be generally applicable to diagnosis of the chirality of the isolated molecules in gas phase.