  Extensive density-functional calculations on atomic chemisorption of H, B, C,
N, O, F, Al, Si, P, S, and Cl on the polar TiC(111) and TiN(111) yield similar
adsorption trends for the two surfaces: (i) pyramid-like adsorption-energy
trends along the adatom periods; (ii) strongest adsorption for O, C, N, S, and
F; (iii) large adsorption variety; (iv) record-high adsorption energy for O
(8.4-8.8 eV). However, a stronger adsorption on TiN is found for elements on
the left of the periodic table and on TiC for elements on the right. The
results support that a concerted-coupling model, proposed for chemisorption on
TiC, applies also to TiN.
