Electron distribution in water

The x-ray structure factor of water measured under ambient conditions with synchrotron radiation is compared with those predicted on the basis of part ial structure factors describing the nuclear positions obtained by neutron diffraction and of different assumptions for the electron distribution. The comparison indicates that a charge of approximately 0.5 e is transferred f rom each hydrogen atom to the oxygen on the same molecule, implying an effe ctive dipole moment of 2.9 D, in good agreement with theoretical estimates. (C) 2000 American Institute of Physics. [S0021- 9606(00)02421-1]