3-4 设a为晶格常数,d为晶面间距 2d sina=ka a sine=ka k=1,2,3,… k=1,2,3,… d=0.18mm,a=30°,k=1● =2× d sina c 2×0.18×sin30°=0.18mm h663×10-34 ∷P-元 0.18×10 368×10kg·m/s··● 3.68×10 24 k2m2×1.67×10-27 4.06×10 21 =406×10-21() 1.60×10-19=0.025(eV1,2,3, sin = = k a  k 1,2,3, 2 sin = = k d  k  d 设a 为晶格常数，d 为晶面间距 a 3-4 d = 0.18nm, = 30 , k = 1 nm d 2 0.18 sin30 0.18 2 sin =    =  =   kg m s h p 3.68 10 / 0.18 10 6.63 10 2 4 9 3 4 =      = = − − −  ( ) ( ) 0.025(e v) 1.60 10 4.06 10 4.06 10 2 1.67 10 3.68 10 2 1 9 2 1 2 1 2 7 2 2 2 4 =   =  =     = = − − − − − J m p Ek 