Nuclear motion quantum calculations have been performed on mono- and bidimensional versions of the potential energy surface for complex [Ru(η2-H2)(C5H5)(H 2PCH2PH2)]+, both with the Discrete Variable Representation (DVR) and Finite Basis Representation (FBR) methodologies. It is found that the DVR methodology produces accurate vibrational energy levels and wave functions at a much lower CPU cost. The DVR results are then used to carry out a study of the vibrational modes. Remarkable agreement between the calculated and the experimental transitions for this complex is found, for both the (η2-H2) and (η2-D2) isotopomers. It is found that the H-H and Ru-H2 stretchings are thoroughly mixed in this complex. Finally, it is seen that the experimental assignments of the vibrational transitions as H-H and Ru-H2 symmetric stretch should be revised.