The two fragmentation schemes of the bis-nitronyl nitroxide molecules. Different combinations of the numbered fragments of (a) and (b) gives the cases of Table II.
1,4-bis-nitronylnitroxide benzene (para) (a) and 1,3-bis-nitronylnitroxide benzene (meta) (b).
energy splitting vs the number of MOs considered in the CI (the number of doubly occupied MOs is 52), for the para and meta phenyl bridged bis nitronyl nitroxide diradicals (Fig. 1) from CI calculations using the SCF, CASSCF, canonical, and localized MOs in the two-fragment (2F) scheme (upper) and localized CASSCF MOs in the n-fragment schemes of Table II (lower). Experimental data from Refs. 43 and 44.
1,4-bisnitronyl benzene (N-para) (a) and 1,3-bisnitronyl benzene (N-meta) (b).
energy splitting vs the number of MOs considered in the CI (the number of doubly occupied MOs is 25), for the N-PARA and N-META species (Fig. 4) from CI calculations using the SCF, CASSCF, canonical and localized MOs in the two-fragment (2F) and three-fragment schemes of Table II.
Excess spin Mulliken population analysis for the N-meta and N-para systems in the triplet state with . First row: UHF calculation, second row (bold): CI calculation.
MO diagram for the para biradical. Left: antisymmetric manifold. Right: symmetric manifold.
MO diagram for the meta biradical. Left: antisymmetric manifold. Right: symmetric manifold.
Examples of the three kinds of E configurations. From left to right: neutral spin polarization, neutral without spin polarization, CT. The labels j, x, a, and b refer to core, empty, and magnetic MOs, respectively.
Composition of the CI space in terms of the number of core, magnetic, and empty MOs (Ref. 27).
Fragmentation cases based on the scheme of Fig. 1 (see text). The MOs localized on the fragments not listed in the last column (neglected MO) are included in the one-electron space of the CI calculations.
Absolute and relative energies (Hartree) of the triplet state for several types of calculations for the N-para and N-meta species of Fig. 4.
The overlap between the magnetic MOs as resulting from ROHF of the triplet state and the benzene MOs.
CI results for several choices of configurations from those reported in Table I. SD is Slater determinant.
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