"Quantum Correction for Electron Transfer Rates: Comparison of Polarizable Vs Nonpolarlizable Descriptions of Solvent," X. Song and R. A. Marcus, J. Chem. Phys., 99, 7768 (1993).

"Theoretical Study of Intramolecular Vibrational Relaxation of Acetylenic CH vibration for v=1 and 2 in Large Polyatomic Molecules (CX₃) ₃YCCH, where X=H or D, Y=C or Si," A. A. Stuchebrukhov and R. A. Marcus, J. Chem. Phys., 98, 6044 (1993).

"Scanning Tunneling Microscopy Theory for an Adsorbate: Application to Adenine Adsorbed on a graphite Surface," H. Ou-Yang, R. A. Marcus and B. Kallebring, J. Chem. Phys., 100, 7814 (1994).

"Theoretical Study of Electron Transfer in Ferrocytochromes," A. A. Stuchebrukhov and R. A. Marcus, J. Phys. Chem., 99, 7581 (1995).

"Solvent-dynamics modified RRKM theory in clusters," R. A. Marcus, Chem. Phys. Lett., 244, 10 (1995).

"Global Potential Energy Contour Plots for Chemical Reactions. Stepwise vs Concerted 2+2 Cycloaddition," R. A. Marcus, J. Am. Chem. Soc., 117, 4683 (1995).

"Tunneling Matrix Element in Ru-Modified Blue Copper Proteins: Pruning the Protein in Search of Electron Transfer Pathways," J. N. Gehlen, I. Daizadeh, A. A. Stuchebrukhov, and R. A. Marcus, Inorg. Chim. Acta, 243, 271 (1996).

"Electron Transfer Reactions in Chemistry. Theory and Experiment," R. A. Marcus, in Protein Electron Transfer , D. S. Bendall, ed., Bios Scientific, Oxford, 1996, Chap. 10.

Professor Marcus' group formulates and investigates theories of chemical reactions, including electron transfer processes, unimolecular reactions, scanning tunneling microscopy, and intramolecular dynamics.

Intramolecular redistribution of vibrational energy in isolated molecules has been the subject of intensive recent experimental investigations, particularly using laser techniques. To interpret the results, the anharmonic vibrational motion of molecules, including the nature and onset of statistical behavior, has been studied. Millions of vibrational-rotational states of the molecule are potentially involved in the intramolecular motion, and we have been using an artificial intelligence searching method to select a subset of these states to treat it. Typically the intramolecular energy exchange was found to be a "vibrational superexchange." The "channel three" problem in benzene and the persistence of CH vibration excitation in other systems were among those studied. Experimental spectral properties of various vibrationally-hot molecules are being investigated in this way. Recently a theory of unimolecular reactions in clusters was developed here, and is being extended.

In the field of electron transfer reactions, the most recent studies in our group include the effects of solvent dielectric dispersion and of donor/acceptor electronic coupling on the reaction rates. The dependence of the electronic coupling matrix elements in electron transfer reactions on the intervening molecular bridge has been treated for a number of rigidly bridged systems and compared with the experimental data. The method has been extended to electron transfers in proteins, initially using the artificial intelligence (AI) method to select the more important amino acids involved in donor/acceptor electron transfers. The mechanism is principally one of electronic superexchange, and the theoretical method used is related to that we employed for the vibrational problem. Most recently, a fast "sparse matrix" technique has been used to include all of the amino acids in the treatment and to test the AI results.

A related problem, the scanning tunneling microscopy of adsorbates on metals and semimetals is being investigated, and is aimed at treating new experimental observations.

The group has also investigated electron transfer rates across several interfaces: liquid-liquid, semiconductor-liquid, metal-liquid, and across ordered monolayers at electrodes. Additional electron transfer studies here include electron transfers in photosynthesis.