AN EXPERIMENTAL-STUDY OF HF PHOTODISSOCIATION - SPIN-ORBIT BRANCHING RATIO AND INFRARED ALIGNMENT

Single rotational levels of HF (v=3) were prepared by using overtone e xcitation and these molecules were then photodissociated by ultraviole t (UV)radiation at 193.3 nm. Time-of-flight spectra of the hydrogen at om fragment provided the spin-orbit state distribution of the fluorine fragment. Changing the UV photolysis laser polarization confirmed an A (II)-I-1<--X (1) Sigma(+) electronic transition in the photodissocia tion step. Photodissociation of HF at 121.6 nm is also reported. Infra red (IR) induced alignment of the diatom was studied by monitoring the IR laser polarization dependence of the H-atom product angular distri bution. Depolarization due to hyperfine interaction was studied by usi ng the R(0) transition. Agreement with theory is excellent. (C) 1996 A merican Institute of Physics.