A Necessary Trade-off for Semiclassical Electrodynamics: Accurate Short-Range Coulomb Interactions versus the Enforcement of Causality?

Tao E. Li, Hsing Ta Chen, Abraham Nitzan, Maxim Sukharev, Joseph E. Subotnik

Research output: Contribution to journalArticle

3 Scopus citations


We investigate two key representative semiclassical approaches for propagating resonant energy transfer (RET) between a pair of electronic two-level systems (donor and acceptor) with coupled Maxwell-Liouville equations. On the one hand, when the electromagnetic (EM) field is treated classically and Coulomb interactions are treated quantum-mechanically, we find that a quantum-classical mismatch leads to a violation of causality, i.e., the acceptor can be excited before the retarded EM field arrives. On the other hand, if we invoke a classical intermolecular Coulomb operator, we find that the energy transfer in the near field loses quantitative accuracy compared with Förster theory, even though causality is strictly obeyed. Thus, our work raises a fundamental paradox when choosing a semiclassical electrodynamics algorithm. Namely, which is more important: Accurate short-range interactions or long-range causality? Apparently, one cannot have one's cake and eat it too.

Original languageEnglish (US)
Pages (from-to)5955-5961
Number of pages7
JournalJournal of Physical Chemistry Letters
Issue number20
Publication statusPublished - Oct 18 2018


ASJC Scopus subject areas

  • Materials Science(all)
  • Physical and Theoretical Chemistry

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