A high-quality x-ray scattering experiment on liquid water at ambient conditions

We report a new, high-quality x-ray scattering experiment on pure ambient w ater using a synchrotron beam line at the Advanced Light Source at Lawrence Berkeley National Laboratory. Several factors contribute to the improved q uality of our intensity curves including use of a highly monochromatic sour ce, a well-characterized polarization correction, a Compton scattering corr ection that includes electron correlation, and more accurate intensities us ing a modern charge coupled device (CCD) detector. We provide a comprehensi ve description of the data processing that we have used for correcting syst ematic errors, and we provide an estimate of our remaining random errors. T he resulting error estimates of our data are smaller then the discrepancies between data sets collected in past x-ray experiments. We find that the ol der x-ray curves support a family of g(OO)(r)'s that exhibit a smaller firs t peak (similar to2.2), while the current data is better fit with a family of g(OO)(r)'s with a first peak height of 2.8, and systematic shifts in all peak positions to smaller r. (C) 2000 American Institute of Physics. [S002 1-9606(00)50744-2].