We present a physical model that explains the dependence of UV cross section ClOOCl on temperature in actinic wavelength region measured before by J.J. Lin, A.F. Chen and Y.T. Lee [Chemistry — An Asian Journal, 6, 1664–1678 (2011)]. It was unclear why there are frequency regions which decreases with increasing others it increases. This interesting behaviour is now shown to be due non-rigidity m...