With a high resolution cross-correlation time-of-flight technique we have successfully eliminated the component of C2H6 molecules scattered after experiencing a temporary trapping on a LiF(001) surface at 300 K. The incident translational energies of C2H6 molecules are varied in the 260-700 meV range and the azimuthal directions of incidence are set at [100] and [110]. While the major peak in each of the time-of-flight spectra, which consists of rotationally excited C2H6 molecules upon single collision, can be well reproduced by a shifted Maxwell-Boltzmann speed distribution function, the temporarily trapped component is fitted to a single Maxwellian distribution with a characteristic temperature slightly higher than the target surface temperature. This temperature tends to increase from around 300 to 600 K with the translational energy of the incident C2H6 beam. The mean translational energy of the temporarily trapped component does not show any special angular dependencies in contrast to that of the directly scattered component which qualitatively follows the washboard model predictions. Temporarily trapped molecules are believed to be the ones which during the first few bounces have stored their translational energy in form of rotation, either cartwheel or helicopter mode, and tangential motion on a corrugated LiF(001) surface.