Conventional ab initio methods face difficulties when they are applied to huge high-spin open-shell systems such as organic ferromagnets due to the quick increase of CPU time relative to the size of the system. Introduced to solve this problem, the minimized mixing elongation (MMELG) method is a linear-scaling quantum chemical method that utilizes minimized mixing and regional localized molecular orbitals to treat the system with constant size at each elongation step. The Lmin method with an index Lmin is combined with the MMELG method to design organic ferromagnets. Predicting the high spin stability of organic radicals correctly for designing organic ferromagnets remains a significant challenge. We have developed a method with an index (Lmin) for predicting the high spin stability of conjugated organic radicals at the restricted open-shell Hartree-Fock level. Unitary transformations were performed for localizing the coefficients of nonbonding molecular orbitals, and subsequently the localized coefficients were used to calculate Lmin that indicates the high spin stability of conjugated organic radicals. This method can be combined with the elongation method to treat huge high spin open-shell systems. Thus, this method is useful for designing organic ferromagnets.
All Science Journal Classification (ASJC) codes
- Computational Mathematics