NMR study of electronic properties of the chemisorption of CO on supported Pt catalysts

The authors have analyzed the ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ spin-lattice relaxation of CO chemisorbed on supported Pt particles. They fit their relaxation data with a minimum set of relaxation times ($T_1$) ranging from 0.009 to 6 s at 77 K. They find that each $T_1$ component is inversely proportional to the temperature, but that some $T_1$ components do not satisfy the Korringa relationship. They express the relaxation by conduction electrons in terms of tight-binding coefficients and evaluate the amount of mixing of the CO orbitals with the Pt conduction bands to account for the observed $T_1$. They also analyze data for CO on Ir and Pd.