Table 2.

Relative peak intensity of the XPS C(1s) lines at the given binding energies for A, C, G, T, U powders from ref. 16 and for the corresponding XPS C(1s) observed from formamide on TiO2 (001) surface

Relative intensity,* a.u.
Energy, eV A C G T U Attribution 300 K 450 K 600 K 700 K
285 6 13 9 14 10 C-H; C-C 9 9 8 8
286-287 13 11 12 7 8 C-Nx 12 13 11 8
288 0 13 11 6 3 Amide 51 46 46 24
289-290 0 6 0 7 13 Urea 22 24 20 15
>290 28 24 25 17
  • A, adenine; C, cytosine; G, guanine; T, thymine; U, uracil; a.u., arbitrary units.

  • * Calculated from ref. 16.

  • Calculated from Fig. 2c.