Sentence:  By comparing reaction cells sealed from the same manifold temperature dependency corresponding to <WSD>activation</WSD> energies ranging from 11 to 18 * * f was observed while dependence on the first power of the light intensity seemed to be indicated in most cases . 
Meaning of the word marked with <WSD> tags:  the energy that an atomic system must acquire before a process (such as an emission or reaction) can occur