Rudolph Arthur Marcus (born July 21, 1923) is a Canadian-born American chemist who received the 1992 Nobel Prize in Chemistry[3] "for his contributions to the theory of electron transfer reactions in chemical systems".

[5][6][7] He is a professor at Caltech, Nanyang Technological University, Singapore and a member of the International Academy of Quantum Molecular Science.

At McGill, Marcus took more math courses than an average chemistry student, which would later aid him in creating his theory on electron transfer.

After graduating, in 1946, he took postdoctoral positions first at the National Research Council (Canada),[15] followed by the University of North Carolina.

It consists of one outer-sphere electron transfer between substances of the same atomic structure likewise to Marcus’s studies between divalent and trivalent iron ions.

Electron transfer may be one of the most basic forms of chemical reaction but without it life cannot exist.

An example of this type of chemical reaction would be one between a divalent and a trivalent iron ion in an aqueous solution.

In Marcus's time chemists were astonished at the slow rate in which this specific reaction took place.