Theoretical valence XPS and UV-visible absorption spectra of four leucodyes using MO calculations

Semiempirical HAM/3 MO program was used to obtain the theoretical valence X-ray photoelectron spectra (XPS) of the two leuco dyes (2’-anilino-6’-diethylamino-3’-methylspiro[isobenzofuran-1(3H),9’-[9H] xanthene]-3-one (DEAMAF) and 3,3-bis(4-dimethylaminophenyl)-6-dimethylamino-1(3H)-isobenzofuranone (CVL)) and UV-visible adsorption spectra of the four leuco dyes (DEAMAF, CVL, 2’-chloro-6’-diethylamino-3’-methylspiro[isobenzofuran-1 (3H),9’-[9H]xanthene]3-one (DEAMCF), and 3’,6’-bis(diethylamino)-spiro [isobenzofuran-1 (3H),9’-[9H]]xanthene]-3-one (Rhodamine B base). The calculated Al K alpha photoelectron spectra were obtained using Gaussian lineshape functions of an approximate linewidth 0.10E(k) (E-k = E’(k) -WD), where E’(k) is the vertical ionization potential (VIP) of each MO and WD is a shift to account for sample work function, polarization energy and other energy effects. On the other hand, the absorption curves were simulated with Gaussian lineshape functions of a constant linewidth of 0.02 eV. The theoretical valence energy levels corresponded well to the spectra of two leuco dyes observed 0-40 eV, while the simulated adsorption spectra were shifted for a good fit with the experimental solution spectra in the range of 250-700 nm.