  Analysis of high spectral resolution observations of the $\lambda$6614
diffuse interstellar band (DIB) line profile show systematic variations in the
positions of the peaks in the substructure of the profile. These variations --
shown here for the first time -- can be understood most naturally in the
framework of rotational contours of large molecules, where the variations are
caused by changes in the rotational excitation temperature. We show that the
rotational excitation temperature for the DIB carrier is likely significantly
lower than the gas kinetic temperature -- indicating that for this particular
DIB carrier angular momentum buildup is not very efficient.
