Detection of "ended'' NO recoil in the 355 nm NO2 photodissociation mechanism

Circularly polarized 1 + 1' REMPI with ion imaging detection was used to pr obe mu-v-j angular correlations of the NO (X (2)Pi(1/2,3/2), upsilon = 0) p hotoproduct from linearly polarized 355 nm photodissociation of NO2 in a mo lecular beam. Rotational angular momentum orientation was measured for the NO product, with the sense and magnitude of the orientation depending upon the direction of the NO recoil velocity with respect to the polarization ve ctor of the photolysis light. The rotational orientation is shown to origin ate from the directionality of the torque responsible for NO rotational mot ion. The experimentally observed sense of rotation in the plane of the NO2 parent molecule is consistent with an effective recoil impulse force applie d to the N end of the NO product. A preliminary measure of the bipolar mome nt associated with this orientation for the j = 21.5 and j = 36.5 rotationa l levels gives a value of approximately beta(0)(2)(21) = 0.2. (C) 1999 Amer ican Institute of Physics. [S0021-9606(99)01236-2].