The dissociation dynamics of the B 2~: state of N3 were investigated using fast radical beam photodissociation coupled with a new coincidence wedge-and-strip-anode particle detector. With this detector, detailed photofragment kinetic energy and angular distributions can be measured as a function of excitation energy. Calibration of the detector by studies of the predissociation of the O 2 B 3~; state is discussed. Methods of extracting the center-of-mass kinetic energy and angular distributions are presented. The photodissociation results for N3 show that from the vibrationless level of the B 2~: state in N 3 , both spin-allowed [Nr-+Ne D) +N2e~:)] and .. §pin-forbidden [N3->N(4S) +N2e~:)] dissociation processes occur. Bend excitation in the B 2~: state, however, enhances the spin-allowed dissociation process considerably. The kinetic energy distributions reveal partially resolved vibrational structure in the N2 fragment, and indicate substantial rotational excitation 0Lthe N 2 . This implies that bent geometries playa major role in the dissociation of the N3 B state. Possible mechanisms for the spin-forbidden and spin-allowed dissociation channels are discussed.2616

Articles you may be interested inTime evolution of the lowest singlet states of Z-1,3,5-hexatriene and 1,3-cyclohexadiene studied by femtosecond photoionization AIP Conf.A system for time and angleresolved photoelectron spectroscopy based on an amplified femtosecond titanium:sapphire laser system Rev.Femtosecond timeresolved ionization spectroscopy of ultrafast internalconversion dynamics in polyatomic molecules: Theory and computational studies J. Chem. Phys. 95, 7806 (1991); 10.1063/1.461816Femtosecond timeresolved spectroscopy of coherent vibrational and electronic excitations in solids AIP Conf.Ultrafast photodynamics in a 1,3,5-hexatriene are studied using femtosecond time-resolved photoionization and photoelectron spectroscopy. The trans and cis isomers have distinctly different dynamics following excitation at the S 2 origin near 250 nm. An intermediate, presumably the S 1 state, is observed for both trans and cis isomers with lifetimes of 270 fs and 730 fs, respectively. Time-delayed photoelectron spectra of cis-hexatriene determine a 300 fs time scale for vibrational energy redistribution within the intermediate S 1 state.

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