Chemisorption of gas atoms on one-dimensional transition-metal halides

We study computationally the bonding of hydrogen and oxygen to one-dimensional materials with the formula XY, where X represents Ti, Zr, or Hf and Y represents a halogen atom Cl, Br, or I. The materials consist of chains of transition metal atoms surrounded by halogen atoms with a three-fold rotation symmetry. The chemisorption leads to a reduction in the number of d-electrons in the materials accompanied by significant changes in Fermi energy. The chemisorption energies are seen to correlate with the work functions of the clean systems supporting the view that electron transfer plays a major role in the bonding.