The centrifugal force in a rotating molecule influences the intensity of spectral lines. This effect is quantified by the so-called Herman-Wallis factor, but its calculation is rather involved and the result is uncertain for Q-branch Raman transitions. This Letter discusses the reliability of various predictions by means of an experimental proof based on coherent anti-Stokes Raman scattering from H-2 molecules. (c) 2007 Elsevier B.V. All rights reserved.