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KR Wilson

Publications and source records attributed to KR Wilson.

3 recordsLinked to original sources
PubMed2000

Extended X-Ray absorption fine structure from hydrogen atoms in water

We report the first quantitative measurement of extended x-ray absorption fine structure (EXAFS) from hydrogen atoms. A single oscillation is observed from gaseous water consistent with the location of the covalently bonded hydrogen in H 2O. The experimental phase and amplitude of the oscillation are in excellent agreement with curved wave multiple scattering calculations for isolated water molecules. With this determination of the O-H scattering phase shift we have quantified the covalent hydrogen bond distance (0.95+/-0.03 A) in liquid water, thus demonstrating that hydrogen EXAFS can become a valuable complement to existing structural methods in chemistry and biology.

Journal Article↗
PubMed1998

3D microscopy of transparent objects using third-harmonic generation.

It is demonstrated that third-harmonic generation (THG) near interfaces in the refractive index or the third-order nonlinear susceptibility (chi(3)) permits three-dimensional imaging of transparent objects. The nonlinear dependence of THG on the excitation power provides inherent optical sectioning. At the same time, the nonresonant nature of THG, in combination with the near-IR excitation wavelengths used (1-2 µm), render this technique potentially (biologically) nondamaging and nonbleaching. A specific property of THG imaging is its sensitivity to - and potential use for imaging of - the relative orientation of interfaces with respect to the axis of propagation of the excitation radiation.

Journal Article↗