It is indicated in this paper that relative annihilation intensity
Ii(0)
which comes from the analysis of the lifetime spectrum and is usually regarded as a basis of discussion on the experiment
dose not always have exact physical meaning. Instead
either the relative population of positrons in the ith state
Ni(0)
or the probability density of positrons distributed in the states
ni(0)
being equal to Ni(0)/∑Ni(0) = τiIi(0)/∑Ni(0)
has obvious connection physically with the structure and characters of the annihilation medium. A proof of the above propositions based on the two- state capture model is given.