Anharmonicity and thermal expansion in crystalline germanium

K-edge EXAFS has been measured in c-Ge from 10 to 600 K. The first-shell co ntribution has been analyzed by the cumulant method. A resolution better th an 10(-3) Angstrom in the relative values of the Ist cumulant has allowed a n accurate study of thermal expansion. For the first time the ratio between perpendicular and radial correlation terms has been experimentally evaluat ed and low temperature quantum effects in the 3rd cumulant have been observ ed.