Naslov
Semiempirical calculation of the ESCA chemical shifts of the group IVA elements in a chemical environment

Autori
Kovaček, Damir ; Maksić, Zvonimir B. ; Petanjek, Ines ; Bašic, Ivan

Izvornik
Journal of molecular structure. Theochem (0166-1280) 305 (1994), 10; 261-281

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
ESCA shift ; inner-core photoionization ; relaxation energy

Sažetak
The electron spectroscopy for chemical analysis (ESCA) chemical shifts of the C(1s), Si(2p3/2), Ge(3p3/2), Ge(3d5/2), Sn(3d5/2) and Sn(4d5/2) levels were considered at the semiempirical level of theory. It was shown that the C(1s) and Si(2p3/2) inner-core energy shifts are satisfactorily accounted for by the SCC-MO method within the relaxation potential (RPf) model. Surprisingly, the more usually used MNDO, AM1 and PM3 methods fail in this regard. The chemical shifts Ge(3p3/2) and Ge(3d5/2) were well described by the PM3/RPf scheme, whereas the best method for estimating the Sn(3d5/2) and Sn(4d5/2) inner-core photoionzation changes in a chemical environment was the PM3/GSP model. The latter makes use of the ground-state potential only. The role of the relaxation energy is discussed and the magnitude of this quantity is interpreted in a transparent and physically meaningful way by using a particular partitioning technique. The use of ESCA shifts and relaxation energies in designing better semiempirical methods is strongly recommanded.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

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