Study of the subpicosecond rotational molecular dynamics in liquids

The parameters of the femtosecond vibration–rotation molecular dynamics of liquid acetonitrile CH₃CN, trimethylacetonitrile (CH₃)₃CCN, propionitrile CH₃CH₂CN, fluoroform CHF₃, and chloroform CHCl₃ are found by analysing the ultrafast optical Kerr effect. The influence of the molecular structure on the features of rotational (diffusion and libration) motions is studied. It is shown that the distribution of libration frequencies is described by the Maxwell distribution.