A new continuous configuration time-dependent self-consistent field method has been developed to study polyatomic dynamical problems by using the discrete variable representation for the reaction system, and applied to a reaction system coupled to a bath. The method is very efficient because the equations involved are as simple as those in the traditional single configuration approach, and can account for the correlations between the reaction system and bath modes rather well. © 2005 American Institute of Physics. ͓DOI: 10.1063/1.1869496͔The last decade has witnessed significant progress in quantum mechanical studies of dynamical chemical processes at the molecular level. The development of the timedependent wave packet ͑TDWP͒ method has made it possible to perform exact quantum mechanical calculations for four-atom systems. [1][2][3][4] The recent report on the state-to-state integral cross sections for the H + H 2 O reaction suggests that we are close to solving four-atom reactive scattering problems completely. 2 The grand challenge in the field of quantum dynamics now is to develop practical yet accurate methods to study polyatomic dynamical problems involving many atoms. However, due to the fact that computational effort grows exponentially with dimensionality, it is impractical at present to study polyatomic dynamical processes exactly in full dimensions although there has been some progress in this direction. 5 Naturally, one has to resort to the reduced dimensionality approach to cut down the number of degrees of freedom included in dynamical studies, or some computational approximate methods to overcome the scaling of effort with dimensionality.A promising approach is the time-dependent selfconsistent field ͑TDSCF͒ method. [6][7][8][9][10][11][12][13][14][15] In the simplest version, i.e., the single configuration time-dependent self-consistent field ͑SC-TDSCF͒ approach, the wave function of the system is written as a direct product of the wave functions for subsystems. [7][8][9][10]12 A principal drawback of SC-TDSCF is that it replaces exact interaction between subsystems by meanfield coupling, resulting in the lack of correlations between subsystems. One way to account for the important correlations neglected in SC-TDSCF is to add wave functions with different configurations to give more flexibility to the wave function of the system, resulting in the so-called multiconfiguration time-dependent self-consistent field ͑MC-TDSCF͒ method. 6,13-15 Wave functions with different configurations are usually constructed by imposing orthogonal condition explicitly, making it hard to use more than a few configurations in numerical implementation. Furthermore, the resulting equations for MC-TDSCF are very complicated compared to those in SC-TDSCF method. For these reasons, MC-TDSCF has only been applied to some model problems. The closely related multiconfiguration time-dependent Hartree method ͑MCTDH͒ generalizes MC-TDSCF in a systematic way, thus eliminating the need for choices of the TDSCF states. 16,17 It ha...