spin-state transition

An electronic transition from a @[email protected] state to a @[email protected], or vice versa. Example: With an increase in temperature Co3+ ions in LaCoO3 transform from a @[email protected] (\(\text{t}_{\text{2g}}^{6}\text{e}_{\text{g}}^{0}\)) to the @[email protected] state (\(\text{t}_{\text{2g}}^{4}\text{e}_{\text{g}}^{2}\)).
PAC, 1994, 66, 577. (Definitions of terms relating to phase transitions of the solid state (IUPAC Recommendations 1994)) on page 591 [Terms] [Paper]