PHOTODISSOCIATION DYNAMICS OF NH2OH FROM THE FIRST ABSORPTION-BAND

The dynamics of the photofragmentatian of hydroxylamine from its lowes t excited electronic state, A (1)A', have been investigated. The main dissociation channel leads to H+H+HNO with a quantum efficiency of 1.7 for hydrogen atoms. The H atoms have been analyzed by laser induced f luorescence using st frequency tripled dye laser with sub-Doppler reso lution. A sequential decay process is proposed where the first ejected H fragment leave's a highly vibrationally excited intermediate which dissociates after intramolecular vibrational redistribution into H+HNO . Another photodissociation channel leads to OH(X (II)-I-2) and NH2(($ ) over tilde A (2)A(1)). NH2(($) over tilde A) has been detected by it s emission spectrum, ($) over tilde A (2)A(1) --> ($) over tilde X B-2 (1), indicating strong vibrational excitation of the v(2) bending mode . The OH product shows no vibrational excitation, whereas rotational s tates up to N = 20 have been observed. Observation of the product stat e distributions and of the (mu.v) and (v.J) correlations yield a quali tative picture of the upper potential energy surface (PES). Out of the nine coordinates characterizing the normal vibrational modes of H2NOH only the NO distance, the NOH bending angle (responsible for OH rotat ion), and the NH2 bending angle (responsible for NH2 bending motion) a re involved in the NH2+OH fragmentation channel.