[en] The energy distribution of ⁸Li fragments emitted from K^- captures in nuclear emulsion is examined with the predictions of evaporation theory. It is observed that high production rate of low energy ⁸Li cannot be explained on the basis of the evaporation theory, even if effects of the penetration of potential barrier during evaporation are taken into account. Calculations indicate that penetration of potential barrier accounts only for approximately 15% of the observed low energy (E<= 20 MeV)⁸Li fragment. The reduction of potential barrier is estimated from Monte-Carlo results and it is observed that it can enhance the production frequency of such ⁸Li by approximately 10%. (author)