Magnetic properties and tunnel exchange states of dimeric mixed-valence clusters with two-electron transfer

Electric Field Effects on Magnetic and Polarizability Properties of Clusters with Two-Electron Transfer

“…Its eigenvalues depend on two transfer parameters p and t . The parameter p describes the monoelectronic transfer that couples the configuration d a 1 –d b 3 and d a 3 –d b 1 with the configuration d a 2 –d b 2 , while the parameter t corresponds to bielectronic transfer, which mixes the states arising from configurations d a 1 –d b 3 and d a 3 –d b 1 . , In ref it was demonstrated that the contribution that comes from the d a 2 –d b 2 configuration is essential for the description of the magnetic and spectroscopic characteristics of the cluster under examination, and, therefore, it is taken into account in the model suggested below. The configuration with equal number of electrons on each center of the binuclear mixed-valence cluster was examined later in ref as well.…”

“…In the basis of states (3) the matrix of the total Hamiltonian is determined as Here, the monoelectronic transfer parameter p connects the states that originate from configurations d a 1 –d b 3 (d a 3 –d b 1 ) and d a 2 –d b 2 , while the parameter t in (5) describes the transfer of two electrons between configurations d a 1 –d b 3 and d a 3 –d b 1 . , The contribution of the electronic configuration d a 2 –d b 2 is included in consideration as in refs and . The parameter U accounts for the difference in the Coulomb repulsion in configurations d a 1 –d b 3 (d a 3 –d b 1 ) and d a 2 –d b 2 of the cluster.…”

“…The parameter U accounts for the difference in the Coulomb repulsion in configurations d a 1 –d b 3 (d a 3 –d b 1 ) and d a 2 –d b 2 of the cluster. Since the Coulomb repulsion is weaker for the d a 2 –d b 2 configuration as compared with that for configurations d a 1 –d b 3 and d a 3 –d b 1 as distinguished from ref the parameter U is taken with a negative sign. The system behavior in the constant electric field is governed by four nondimensional parameters x = J /| p |, u = U /| p |, ε = t /| p |, and y = d 0 E /| p |.…”

“…2 ,41 while the parameter t in(5) describes the transfer of two electrons between configurations d a 1 −d b 3 and d a 3 −d b 1 . 41,42 The contribution of the electronic configuration d a 2 −d b 2 is included in consideration as in refs 41 and 43.…”