Use of a dynamic shift scheme for the levels of Brillouin states in the super-CI method
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We propose a dynamic shift method for the levels of the Brillouin states, providing reliable and sufficiently rapid convergence of the iteration process in the CASSCF method with optimization of the orbitals according to the super-CI scheme. In each step of the super-CI procedure, the shift parameters are determined automatically and individually for each Brillouin state. The proposed method is simple and easy to carry out. It also guarantees that a physically incorrect solution cannot appear. The method was carried out using the CASSCF programming package; for the example of specific calculations for the1Σ+ state of the TiO molecule, we show that the method is efficient and preferred.
KeywordsProgramming Package Iteration Process Specific Calculation Shift Parameter Rapid Convergence
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