A photoabsorption, photodissociation and photoelectron spectroscopy study of NH₃and ND₃

The absolute photoabsorption, photoionization and photodissociation cross sections and the photoionization quantum efficiency of ammonia and deuterated ammonia have been measured from the ionization threshold to 25 eV using a double ion chamber and monochromated synchrotron radiation. The photoabsorption spectrum displays extensive vibrational progressions associated with Rydberg series converging onto excited vibrational levels of the 2A2´´ state. New structure has been observed for ND3 in the 10.0-11.3 eV range, and vibrational progressions due to transitions into the , and Rydberg states have been recorded with improved resolution. Features have been observed, for the first time, in the photoabsorption spectra of NH3 and ND3 due to Rydberg series converging onto the à 2E ionization threshold, and interpretations for some of these features have been proposed based upon the corresponding photoelectron spectra.