|
| |
 |
Daniel M. Chipman
Iowa State University, B.S. ('67)
University of Wisconsin, Ph.D. ('72)
Tel. (574) 631-5562
e-mail: chipman.1@nd.edu
Electronic Structure in Solution
|
Scientific Interests
Theoretical studies of free radicals
vibrational force fields; spin density; excitation
energy; large amplitude internal motion
Solvation effects reaction field modeling; hydrogen bonding; ionic strength effects; dispersion and cavitation corrections
Recent Accomplishments | Top |
Excitation of Water — The lowest excited electronic state of water is well known to be dissociative in an isolated gas phase monomer. However, we have established that the excited potential surface instead becomes quasibound when the OH moiety is hydrogen bonded to a neighboring water molecule. This has important ramifications for the behavior of excited liquid water and ice, newly raising the possibility of energy transport over substantial distances by migration of a neutral exciton.
Solvation effects — An improved boundary element method has been developed to represent the influence of dielectric solvation on the electronic structure of a solute molecule. Rarely recognized yet important effects of volume polarization due to solute charge penetration outside the cavity nominally enclosing it are accurately included. Simple models of specific hydrogen bonding effects on solvation energies have also been developed.
Improved density calculation — New quantum operators have been derived for the difficult problem of evaluating Fermi contact interactions that determine observed EPR hyperfine coupling constants and NMR indirect spin-spin coupling constants. These provide satisfactory accuracy with relatively small basis sets, and thereby extend our capability to treat larger and more complex systems than were previously feasible.
Selected Publications
| Top |
D.M. Chipman
Dissociative electron attachment to the hydrogen-bound OH in water dimer through the lowest anionic Feshbach resonance
J. Chem. Phys. 2007 127, 104309 link
D.M. Chipman
Stretching of hydrogen-bonded OH in the lowest excited electronic state of water dimer
J. Chem. Phys. 2006 124, 044305 link
B.C. Garrett, D.A. Dixon, D.M. Camaioni, D.M. Chipman, et al.
The role of water in electron-initiated processes and radical chemistry: Issues and scientific advances
Chem. Rev. 2005 105, 355-90 link
V.A. Rassolov and D.M. Chipman
Alternative Fermi contact operators for EPR and NMR.
in Calculation of NMR and EPR Parameters. Theory and Application, Edited by M. Kaupp, M. Buhl, and V.G. Malkin (Wiley-VCH, Weinheim, 2004)
D.M. Chipman
Solution of the linearized Poisson-Boltzmann equation
J. Chem. Phys. 2004 120, 5566 link
|