The Hamiltonian becomes H ( r 1 , p 1 , r 2 , p 2 ) = ( 1 − − 1 4 p 1 2 m 1 2 c 2 ) p 1 2 2 m 1 + ( 1 − − 1 4 p 2 2 m 2 2 c 2 ) p 2 2 2 m 2 + q 1 q 2 r − − q 1 q 2 r 1 2 m 1 m 2 c 2 p 1 ⋅ ⋅ [ 1 + r ^ ^ r ^ ^ ] ⋅ ⋅ p 2 .