Abstract
The spin-coupling model of zero-field splitting (ZFS) is developed for trimeric and tetrameric clusters. The spin-dependent correlations between the cluster ZFS parameters Ds and Es and ZFS parameters Di and Ei of individual ions were obtained for the mixed-valent (MV) and monovalent trimeric [3Fe-4S] and tetrameric [4Fe—4S] clusters with high-spin ground states. The cluster ZFS parameters Ds and Es depend on the total spin S and intermediate spins Sij. The model explains the experimentally observed negative Ds of the MV [3Fe-4S]0 (Sgr=2) and [3FeZn-4S]+ (Sgr=5/2) centers and the positive Ds of the tetrameric MV [4Fe—4S]+ (Sgr=3/2) cluster and the monovalent [3Fe-4S]+ trimer (Sgr=5/2) of Pyrococcus furiosus ferredoxin. In distorted trimers and tetramers, the cluster ZFS parameters change value and sign under the variation of isotropic Heisenberg exchange and double exchange due to the exchange admixture of the excited states. The peculiarities of effective hyperfine constants Ai of the [3FeZn-4S]+ cluster with Sgr=5/2 were described in the exchange-resonance model with an admixture of the excited states.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
