Two-photon formation of NH/ND(A 3Π) in the 193 nm photolysis of ammonia. II. Photolysis of NH 2

Abstract

The formation ofNH(A 3Π) in the photolysis of NH 2 ‡ ( X 2B 1), internally excited ground state amidogen prepared by the 1 nm photnlysis of NH 3, has been studied. The alignment of the NH(A 3Π) was determined from the polarization of the NH (A 3Π→,X 3Σ −) fluorescence. The populations of the Λ-doublet states are found to be unequal with preferential population of the “antisymmetric” Λ-doublet. It is concluded that (i) the parent NH 2 ( X 2B 1) is rotationally excited, (ii) the dissociation i the NH 2(2 2A 1) state and (iii) the high rotational excitation of the NH(A 3Π) results from the rotational excitation of the NH 2 ‡( X 2B 1). NH (A 3Π) formed in the 193 nm photolyses of CH 3NH 2 and N 2H 4 and in the 172 nm photolysi generated by mechanisms similar to that in the 193 nm photolysis of NH 3.