Equation Icon  ( ∘ ----------------------------) { ( 0)2 [ ( )2] ( 0) ( 0)2 [ ( )2]2} ω2± = c2 k2 + 2 mu--- 1 + -c0 ± 2 mu--- k2 + mu--- 1 + c0- . (283 ) ( ℏ u0 ℏ ℏ u0 )