In:
The Journal of Chemical Physics, AIP Publishing, Vol. 120, No. 21 ( 2004-06-01), p. 9952-9968
Abstract:
The theory of the J–OC–PSP (decomposition of J into orbital contributions using orbital currents and partial spin polarization) method is derived to distinguish between the role of active, passive, and frozen orbitals on the nuclear magnetic resonance (NMR) spin–spin coupling mechanism. Application of J–OC–PSP to the NMR spin–spin coupling constants of ethylene, which are calculated using coupled perturbed density functional theory in connection with the B3LYP hybrid functional and a [7s,6p,2d/4s,2p] basis set, reveal that the well-known π mechanism for Fermi contact (FC) spin coupling is based on passive π orbital contributions. The π orbitals contribute to the spin polarization of the σ orbitals at the coupling nuclei by mediating spin information between σ orbitals (spin-transport mechanism) or by increasing the spin information of a σ orbital by an echo effect. The calculated FC(π) value of the SSCC J(CC)1 of ethylene is 4.5 Hz and by this clearly smaller than previously assumed.
Type of Medium:
Online Resource
ISSN:
0021-9606
,
1089-7690
Language:
English
Publisher:
AIP Publishing
Publication Date:
2004
detail.hit.zdb_id:
3113-6
detail.hit.zdb_id:
1473050-9
