则定容比热为 elo. tdo aT aT g 把式(3-58 代入上式得到 2 exp(ha/kaT)-1 1.|hO 方o/knT (3-68) B kT B则定容比热为 ( ) ( ) m g E T d T T U C V 0 = = , 把式(3-58’) ( ) () g d e e k T C k k T k T B B B B m 2 2 0 -1 = (3-68) exp( ) −1 1 2 1 k T E B = + 代入上式得到