Walter England

Associate Professor

Office: Chemistry 327
Phone: 414-229-6731
e-mail: england@uwm.edu

Degree(s):

Ph.D., Iowa State University

Research Description:

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.

Fig. 1. Second-order diagram	Fig. 2. rphThird-order ring diagram
Fig. 3 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 surfac

Selected Publications:

"Valence States of BeO Feynman's Way", T.E. Sorensen and W.B. England, International Journal of Quantum Chemistry, submitted (1998).

"Valence States of C2 Feynman's Way", T.E. Sorensen and W.B. England, Chemical Physics, 108, 13, 5205 (1998).

"The Nitrogen System Feynman's Way", T.E. Sorensen and W.B. England, Molecular Physics, 92, 3, 555-567 (1997).

"Valence States of O2 Feynman's Way", T.E. Sorensen and W.B. England, Molecular Physics, 89, 5, 1577-1602 (1996).