Structure of the liquid semiconductor GeSe

The partial structure factors and pair distribution Functions for liquid Ge Se at 727(2) degrees C were measured by using the method of isotopic substi tution in neutron diffraction. The results show that the liquid retains lit tle memory of the high-temperature crystalline phase of GeSe. On melting, t here is a reduction in the Ge-Se coordination number from 6 to 3.2(2) and b oth Ge-Ge and Se-Se homopolar bonds become features of the molten state wit h contact distances of 2.36(2) and 2.34(2) Angstrom and coordination number s of 0.8(1) and 0.22(3) respectively. The results are discussed by referenc e to the structures of molten CuSe and CuBr, which contain electronegative species of the same or similar size. The structure is also compared with th at of the glass-forming network melt GeSe2 and it is found that, unlike the latter, there is no strong indication of intermediate-range atomic orderin g as manifest by a prominent first sharp diffraction peak in one of the mea sured partial structure factors.