We extend the theory of inelastic rainbows to include vibrationally inelastic scattering, showing how the existence of vibrational rainbows can be deduced from collinear classical scattering theory. Exact closehyphen;coupling calculations are carried out for a breathing sphere potential, and rainbow structures are, in fact, observed. The location of the rainbows generally agrees well with the classical prediction. In addition, the sensitivity of the location of the rainbow to changes in the vibrational coupling has been investigated. It is shown that vibrational rainbows persist in the presence of anisotropy. Experimental results lsqb;R. David, M. Faubel, and J. P. Toennies, Chem. Phys. Lett. 18, 87 (1973)rsqb; are examined for evidence of vibrational rainbow structure, and it is shown that vibrational rainbow theory is not inconsistent with these results.
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