ALIGNMENT-ORIENTATION TRANSITION AT OPTICAL-EXCITATION OF MOLECULES IN MAGNETIC-FIELD

Angular momentum alignment-orientation transition is analyzed for the ground state of diatomic or linear molecules subjected to the dynamic Stark effect. Analytical expressions are derived for the orientation v alue. It is shown that, first, orientation of angular momenta resultin g from the action of the dynamic Stark effect is a nonlinear process w hich depends quadratically on the intensity of the irradiating light; second, it is a quantum effect and disappears for the states with larg e angular momenta; and, third, it occurs only in the presence of an ex ternal magnetic field.