Rotational changes accompanying vibrational transfer in low-energy collisions between benzene and H2, D2, and CH4

A variety of rotational-level population distributions are prepared in the 6(super 1) vibrational level of (super 1)B(sub 2u) benzene, and the rotational distributions within 0 degree that result from collisions with H2, D2, or CH4 are observed. The 0 degree distributions for D2 are broader than for H2, illustrating that the reduced mass and rotational-level spacings play an important role in determining the rotational changes that occur.