Walter England

Theoretical Chemistry
Associate Professor
Laboratory for Surface Studies
PhD, Iowa State University
(414) 229-6731
e-mail: england@uwm.edu
Selected Publications

Feynman diagrams are universal pictures of many-particle quantum physics. We have shown that low-order diagrams may be applied to chemical valence and reaction progress coordinates. These low-order diagrams may be calculated orders of magnitude faster than the wave functions needed for traditional quantum chemistry. We are now working out this theory for valence-excited states.

Second-order diagram	rphThird-order ring diagram
lplhThird-order ladder diagrams

Feynman diagrams for polymers, surfaces, or solids may be associated with a lattice. Lines and interactions may be associated with several lattice points. Those from a single lattice point are essentially the same as the Feynman diagrams for chemical valence. Pieces from several lattice points are a new problem and must be summed over some range of the lattice. We are studying the ranges and summation methods which may be used for the low-order diagram in delocalized systems and surfaces.