Vibrational predissociation dynamics of He-I2(B) mediated by orbiting resonances

The He-I(2)(B, v) resonances embedded in the continuum of the v = 60 and 59 vibrational manifolds are investigated. Such states manifest a nature of overlapping and long-lived orbiting resonances, which are supported by centrifugal barriers originated in internal rotational excitation of I(2) and He within the complex. The same number of orbiting resonances, six, is found for v = 60 and for v = 59, with similar energy positions and wave functions, indicating that the spectrum of orbiting resonances changes slowly with the vibrational state v. Three of the orbiting resonances appear at nearly the same energies as the peaks observed experimentally in the vibrational relaxation cross section of I(2)(B, v = 21) through low temperature collisions with He. Such finding suggests that the cross section peaks have their origin in orbiting resonances of the He-I(2)(B, v = 21) complex formed upon the collision.