The theoretical studies on the proton, hydrogen and charge transfer reactions in gas phase, carried out by direct ab-initio dynamics and quasi-classical trajectory calculations, have been reviewed. Especially, we focus our attention on the selectivity of vibrational and rotational states of products in the reactions. The reactions studied are X‾ + HY → HX(v,J) + Y‾ (where X,Y = O, F, Cl) for the proton transfer, A⁺ + BC → A + BC⁺ (v,J) for the charge transfer, and NH₃⁺ + NH₃ → NH4⁺ + NH₂ for the proton and hydrogen atom transfers. In addition, the energy transfer reaction O(¹D) + N2 → 0(³P) + N₂(v,J) in ozone layer has been studied. The results are compared with recent experiments.