Preferred Label : Marcus–Hush relationship;
IUPAC definition : Relationship between the barrier (ΔG‡) to thermal electron transfer, the energy of
a corresponding optical charge-transfer (CT) transition (Δ E op), and the overall
change in standard Gibbs energy accompanying thermal electron transfer (Δ G o). Assuming
a quadratic relation between the energy of the system and its distortions from equilibrium
(harmonic oscillator model) the expression obtained is: \[Δ G {\ddagger} \frac{Δ
E_{{op}} {2}}{4\ (Δ E_{{op}}\,-\,Δ G {o})}\] The simplest form of this expression
obtains for degenerate electron transfer (Δ G o) in e.g. symmetrical mixed valence
systems: \[Δ G {\ddagger} \frac{Δ E_{{op}}}{4}\] Note that for this situation the
Marcus equation reads: \[Δ G {\ddagger} \frac{\lambda }{4}\];
Origin ID : M03703;
See also
Relationship between the barrier (ΔG‡) to thermal electron transfer, the energy of
a corresponding optical charge-transfer (CT) transition (Δ E op), and the overall
change in standard Gibbs energy accompanying thermal electron transfer (Δ G o). Assuming
a quadratic relation between the energy of the system and its distortions from equilibrium
(harmonic oscillator model) the expression obtained is: \[Δ G {\ddagger} \frac{Δ
E_{{op}} {2}}{4\ (Δ E_{{op}}\,-\,Δ G {o})}\] The simplest form of this expression
obtains for degenerate electron transfer (Δ G o) in e.g. symmetrical mixed valence
systems: \[Δ G {\ddagger} \frac{Δ E_{{op}}}{4}\] Note that for this situation the
Marcus equation reads: \[Δ G {\ddagger} \frac{\lambda }{4}\]
