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.
Wilson
KR
Department of Chemistry, University of California at Berkeley, Berkeley, California 94720, USA.
Tobin
JG
Ankudinov
AL
Rehr
JJ
Saykally
RJ