Files
Document type
ArticleVersion
Accepted versionPublication date
All rights reserved
Please use this identifier to cite or link to this item: https://hdl.handle.net/2445/154484
On the zeroth-order Hamiltonian for CASPT2 calculations of spin crossover compounds
Journal Title
Director/Tutor
Journal ISSN
Volume Title
Related resource
Abstract
Complete active space self-consistent field theory (CASSCF) calculations and subsequent second-order perturbation theory treatment (CASPT2) are discussed in the evaluation of the spin-states energy difference (ΔHelec) of a series of seven spin crossover (SCO) compounds. The reference values have been extracted from a combination of experimental measurements and DFT + U calculations, as discussed in a recent article (Vela et al., Phys Chem Chem Phys 2015, 17, 16306). It is definitely proven that the critical IPEA parameter used in CASPT2 calculations of ΔHelec, a key parameter in the design of SCO compounds, should be modified with respect to its default value of 0.25 a.u. and increased up to 0.50 a.u. The satisfactory agreement observed previously in the literature might result from an error cancellation originated in the default IPEA, which overestimates the stability of the HS state, and the erroneous atomic orbital basis set contraction of carbon atoms, which stabilizes the LS states.
Citation
Citation
VELA LLAUSÍ, Sergi, et al. On the zeroth-order Hamiltonian for CASPT2 calculations of spin crossover compounds. Journal of Computational Chemistry. 2016. Vol. 37, num. 10, pags. 947-953. ISSN 0192-8651. [consulted: 10 of August of 2026]. Available at: https://hdl.handle.net/2445/154484