Photodissociation dynamics of the à state NH₃ molecule

The photodissociation dynamics of NH₃ molecules caused by pulsed UV laser excitation from ground state to the v’₂=0-6 vibrational levels to the ùA"₂ electronic excited state has been investigated by monitoring the time-of-flight （TOF） spectra of the nascent H-atom products. The detailed energy disposal in NH₂ （\tilde X） fragments is sensitive to the initially excited vibronic level of parent molecule NH₃ （Ã）: the NH₂ （\tilde X） fragments resulted from the v’₂=0-2 levels of NH₃（Ã）, which tunnel through a potential barrier, populate more in the low N=K_a rotational levels, while that from the v’₂=3-6 levels generate a population in higher N=K_a rotational levels.