Determination of the Mn2+-F- bond length using a complete spectrum criterion and a next nearest neighbor model

A complete spectrum criterion and a next nearest neighbor model are propose d. Research indicates: 1) Using this criterion can remove the long existing puzzle that different parameters produce different bond lengths. The crite rion greatly improve the reliability of optical method for determining the Mn2+-F- distance R. 2) The exponent n and coefficient K in the inverse powe r law 10Dq = KR-n are obviously affected by next nearest neighbor. 3) Consi dering the effect can lead to a better result, the next nearest neighbor mo del is thus more strict and reliable.