“…It is clear that systems displaying a dynamical symmetry can be treated by algebraic methods (Arima and Iachello, 1974;Perelomov, 1985;Wybourne, 1974;Cooper, 1993). To see the ladder operators of a quantum system with some important potentials such as Morse potential the Pöschel-Teller one, the pseudo harmonic one, the infinitely square-well one and other quantum systems refer to , , Dong (2002a,b), Dong and Ma (2002a,b), Dong and Dong (2002a,b), Dong (2003Dong ( , 2004, Dong et al (2003).…”