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In this work the complete valence-band structure of the molybdenum dichalcogenides MoS 2 , MoSe 2 , and ␣-MoTe 2 is presented and discussed in comparison. The valence bands have been studied using both angleresolved photoelectron spectroscopy ͑ARPES͒ with synchrotron radiation, as well as ab initio band-structure calculations. The ARPES measurements have been carried out in the constant-final-state ͑CFS͒ mode. The results of the calculations show in general very good agreement with the experimentally determined valenceband structures allowing for a clear identification of the observed features. The dispersion of the valence bands as a function of the perpendicular component k ជ Ќ of the wave vector reveals a decreasing three-dimensional character from MoS 2 to ␣-MoTe 2 which is attributed to an increasing interlayer distance in the three compounds. The effect of this k ជ Ќ dispersion on the determination of the exact dispersion of the individual states as a function of k ជ ʈ is discussed. By performing ARPES in the CFS mode the k ជ ʈ component for off-normal emission spectra can be determined. The corresponding k ជ Ќ value is obtained from the symmetry of the spectra along the ⌫A, KH, and M L lines, respectively.

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