The angular momentum orientation of C2H2 2(1) and its collisional decay and transfer

The rotational angular momentum orientation of acetylene in vibrationally e xcited discrete rotational states ((X) over tilde(1)Sigma(g)(+), nu(2)" = 1 , J ") has been selectively prepared by circularly polarized laser stimulat ed Raman pumping. From the induced fluorescence by a circularly polarized U V laser, (A) over tilde(1)A(u)(nu(3)' = 1) <--(X) over tilde(1)Sigma(g)(+)( nu(2)" = 1), the orientation of C2H2((X) over tilde(1)Sigma(g)(+), nu(2)" = 1, J = 4, 7, 8, 9, 10, 11, 12, 13) is measured for the first time. The dec ay rate constants and transfer of the orientation from the initial excited level to neighboring rotational states have been extracted.