In water, hydrogen bonds forge links between hydrogen and oxygen atoms in adjacent molecules. Such a bond's character derives mostly from attraction between unlike electric charges that the two types of atoms acquire. However, the new findings show that an electron contributing to that charge separation spends roughly 10 percent of its time mingling with an electron covalently binding the hydrogen and oxygen atoms within the adjacent molecule. The specific 10 percent estimate has not yet been published, he says. In the new experiment, Isaacs' team, which also included scientists at Northeastern University in Boston, the European Synchrotron Radiation Facility in Grenoble, France, and the Canadian National Research Council in Ottawa, Ontario, shone X rays at millimeter-thick crystals of ultrapure ice.
X rays lose some energy and change direction as they strike electrons in the crystal.
By studying X rays bounced off various planes in the crystal with different numbers of hydrogen bonds, the team highlighted features of the bonds. The researchers deduce that the electron wave in each hydrogen bond is interfering with the wave in an adjacent covalent bond. Sticking tough with new hydrogen bonds. Signs of altered bonds in squeezed ice.