Psl occurs while eu2 + transferring from 4fb5d7 to 4f7 or when exciton transferring to 4f7 defectively . we give the physical imagination about several possible migration paths of f center , which offer more full and accurate theory basis to comprehend the cause of psl phenomenon in bafbr : eu2 + crystal 我們詳細給出了在bafbr : eu ~ ( 2 + )晶格中不同位置f心可能移動路徑的物理圖景,從而為更好的理解bafbr : eu ~ ( 2 + )晶格中psl現(xiàn)象的產(chǎn)生提供了更加翔實的理論依據(jù)。