Vibrational lifetimes of aniline–noble gas complexes

The lifetimes of electronic ground state, vibrationally excited aniline–noble gas complexes are measured in pump–probe experiments. When exciting the I02-mode (422 cm−1) of aniline–X (X = Ne, Ar), lifetimes are measured to be 36±3 ns for the neon complex and 151±34 ns for the argon complex. Upon deuteration of the amino group, the frequency of this mode shifts to 335 cm−1 and the lifetimes increase dramatically. Ring deuteration of aniline shortens the lifetime of the vibrationally excited aniline–argon complex to 29±3 ns. Comparison of these results with statistical theory shows non-statistical behavior which is attributed to slow Internal Vibrational Redistribution (IVR).