Three-dimensional quantum reactive scattering calculations have been carried out for the (D + H-2)(+) nonadiabatic ion-molecule collision. The calculations have been done using the time-independent close-coupling formalism with hyperspherical coordinates. The (3 x 3) diatomics-in-molecule potential energy surfaces have been employed. The result of the accurate quantum scattering calculations have been compared to the results of the quasiclassical trajectory surface hopping method. Two versions of the method have been used; one uses Tully＇s fewest switches algorithm and the other is the trajectory surface hopping method of Tully and Preston, in which electronically nonadiabatic hopping is only allowed at the predefined crossing seams. We have found that the agreement between the quantum result and the result of Tully＇s method is generally good, but the Tully and Preston method significantly underestimates the nonadiabatic transition probability. (C) 2000 American Institute of Physics. [S0021-9606(00)01706-2].